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Biomedical subjects

Y Xie

Publications and source records attributed to Y Xie.

At least 127 records · Page 7Linked to original sources

[Investigation of genotyping HLA DRB1 gene using oligoneucleotide arrays].

We have developed a method performed on an oligoneucleotide array for genotyping HLA DRB1. The routine method Phenol-chloroform was used to extract genome DNA of standard samples. A pair of sense and antisense primers were designed according to the sequence of DRB1 exon2, then the primers and the Cy5-dCTP were used in the following PCR, thus the PCR products were labelled with Cy5. Many genotyping probes which were immobilized on the DNA Microarray made by APS-PDC method were designed. The labelled PCR products were hybridized with them, the signals were sanned by sanner and analyzed by Imagene software. We have genotyped 33 standard samples which have 12 DRB1 subtypes. The experimental results showed that the arrays we made and the method we used are accurate and sensitive. This proved that the DNA Microarray technique is good for DRB1 genotyping. Compared with PCR-SSP and PCR-SSO methods, the genotyping chip method is more intuitionistic and has the advantage of integration.

Genotype↗

Chromium (VI)-induced production of reactive oxygen species, change of plasma membrane potential and dissipation of mitochondria membrane potential in Chinese hamster lung cell cultures.

OBJECTIVE: To examine whether Reactive Oxygen Species (ROS) is generated, and whether plasma membrane potential and mitochondrial membrane potential are depolarized in Chinese Hamster Lung (CHL) cell lines exposed to Cr (VI). METHODS: CHL cells were incubated with Cr(VI) at 10 mumol/L, 2.5 mumol/L, 0.65 mumol/L for 3 and 6 hours, respectively. The production of ROS was performed by using 2,7-dichlorofluorescin diacetate; The changes in plasma membrane potential were estimated using fluorescent cationic dye DiBAC4; And the changes in mitochondria membrane potential were estimated using fluorescent dye Rhodamine 123. RESULTS: The ROS levels in CHL cells increased in all treated groups compared with the control group (P < 0.01); The plasma membrane potential and mitochondrial membrane potential in CHL cells dissipated after incubated with Cr(VI) at 10 mumol/L for 3 hours and 6 hours (P < 0.01), at 2.5 mumol/L for 6 hours (P < 0.01 or 0.05). CONCLUSION: Cr(VI) causes the dissipation of plasma membrane potential and mitochondrial membrane potential in CHL cell cultures, and Cr(VI)-induced ROS may play a role in the injuries.

Animals↗

Molecular cloning and characterization of NAG-7: a novel gene downregulated in human nasopharyngeal carcinoma.

OBJECTIVE: To identify novel tumor suppressor genes at chromosome 3p24-26 in human nasopharyngeal carcinoma (NPC). METHODS: Twenty epithelial-derived expressed sequence tags (EST) were selected from chromosome 3p24-26. RT-PCR and Northern blot were used to detect the expression of the ESTs in NPC cell line, HNE-1, and primary cultures of normal nasopharyngeal epithelial cells. One EST, which was substantially downregulated in the HNE-1 cell line, was detected in 19 NPC biopsy samples. cDNA library screening was used to get its full sequence and the sequence of this novel gene was analyzed. RESULTS: A novel gene located at chromosome 3p25.3 was obtained and named NAG-7. It was downregulated in 26.3% (5/19) of NPC biopsy samples. Its 1677 bp full length cDNA had a potential open reading frame predicting a 94 amino acid protein with a molecular weight of 11,023.87 Dalton. Analysis of the NAG-7 gene showed that it was a transmembrane protein containing a protein kinase C phosphorylation site and a myristyl site. It has no significant homology to any reported genes in the database of GenBank. CONCLUSION: NAG-7 is a novel gene downregulated in NPC, suggesting that it may be involved in the development of NPC.

Amino Acid Sequence↗

[The clinical features and prognostic factors of 22 patients with primary central nervous system lymphoma].

OBJECTIVE: The authors present a retrospective analysis of 22 patients with primary central nervous system lymphoma(PCNSL) in order to provide a reasonable basis for the diagnosis and treatment of the disease. METHODS: This report involves a clinicopathological study of 22 patients with histologically proven PCNSL, all diagnosed between January 1993 and May 2000. Univariate and multivariate regression analysis are used to determine prognostic factors significantly associated with an unfavorable or favorable impact on survival. RESULTS: The cohort included 11 men and 11 women whose median age at diagnosis was 49.5 years. At the end point of follow-up, 11 died. The median survival time for the patients in study was 14.5 months. With univariate and multivariate regression analysis, prognostic factors significantly associated with survival included intrathecal injection(P = 0.005) and local/diffuse neurological deficit (P = 0.031). CONCLUSION: There continues to be a significantly increasing incidence of PCNSL. This survey throws light on the clinical and prognostic features of this uncommon disease. Through univariate and multivariate regression analysis the authors highly recommend a therapeutic regime including surgery, intrathecal injection and chemotherapy, especially those drugs capable of passing blood-brain barrier, for example high dose MTX.

Adolescent↗

[Corneal topography and pachymetry in normal eyes].

OBJECTIVE: To evaluate the corneal topography and pachymetry on normal eyes. METHODS: The Orbscan corneal topography system was used to investigate corneal topography and pachymetry on 46 normal subjects. RESULTS: In normal eyes, island-shape was the most common type in the elevation topography of anterior corneal surface, followed by incomplete ridge, regular ridge, irregular ridge and unclassified type. For the elevation topography of posterior corneal surface, the most common type was also the island-shape, followed by regular ridge, incomplete ridge and irregular ridge. The thinnest point of cornea in normal eyes was located (0.90 plus minus 0.51) mm away from the visual axis with the thickness of (0.55 plus minus 0.33) mm, which was commonly seen at the inferotemporal quarter of cornea, followed by superotemporal, inferonasal and superonasal quarter. The mean corneal thickness was the least in corneal center and greatest in superior part of cornea. For the color-coded map of corneal thickness, oval shape was the commonest type, followed by round shape, eccentric oval shape and eccentric round shape. CONCLUSIONS: The normal parameters on pan-corneal thickness and corneal shape of both anterior and posterior surface will provide much more useful informations in finding abnormal cornea. Orbscan topography system is a useful instrument for the evaluation of corneal shape and thickness, which is helpful in corneal refractive surgeries.

Adult↗

[The influence of recombinant human growth hormone on the metabolism of glucose and protein in severely burned patients].

OBJECTIVE: To investigate the influence of recombinant human growth hormone (rhGH) on the metabolism of glucose and protein in severely burned patients. METHODS: The serum levels of total protein and albumin and the incidence of hyperglycemia in 24 cases of severely burned patients treated by rhGH were determined and compared with those in patients without rhGH treatment (control group). RESULTS: The serum levels of total protein (TP) and albumin in burned patients after being treated by rhGH were much higher than those before treatment and those in control group. The blood level of glucose increased within 2 weeks, especially 1 week postburn. The incidences of hyperglycemia were 52.38%, 50.24% and 20% on 0 similar 3, 4 similar 7 and 8 similar 14 postburn days (PBDs), respectively. And the incidences of hyperglycemia were 100%, 50% and 0% when the administration of rhGH started within 1, 2 and after 2 weeks respectively. CONCLUSION: The systemic protein synthesis in severely burned patients could be accelerated by the use of rhGH. But early administration of rhGH in burned patients could affect blood sugar level obviously. And the optimal time to give rhGH is 2 weeks after burn injury.

Adult↗

[High efficient expression of recombinant human platelet factor IV in Pichia pastoris].

OBJECTIVE: To express recombinant human platelet factor 4 (PF4) in methanol yeast. METHODS: PF4 cDNA amplified by PCR was cloned into the mating factor alpha (MFalpha) signal sequence, downstream the alcohol oxidase 1 (AOX 1) promoter of the pPIC9 vector. The reconstructed vector was subsequently integrated into the methanol yeast P. pastoris strain GS115. The highly expressing strain was selected and the protein sequences and their biological activities were assayed. RESULTS: The amino acid sequence of rhPF4 was the same as that of natural one. The rhPF4 can neutralize the anticoagulation effect of heparin in a dose-dependent manner. CONCLUSION: The amount of rhPF4 expressed in methanol yeast meets well the scale for manufacturing. The biological activities of the rhPF4 were the same as that of natural PF4.

Cloning, Molecular↗

[Establishment of EBV-immortalized lymphoblast cell lines from three Chinese Fanconi anemia patient and their subtyping].

OBJECTIVE: To establish EBV-immortalized lymphoblast cell lines from Chinese Fanconi anemia (FA) patients. METHODS: The establishment of lymphoblast cell lines was by EBV-immortalization and subtyping of the cell lines by cell fusion, mytomycin C (MMC) inhibition analysis and/or immunoprecipitation and Western blot. RESULT: (1) Three lymphoblast cell lines were established, two of them were sensitive to MMC with a IC (50) < 10 nmol/L. (2) The subtypes of all the three patients belong to FA-A group. CONCLUSION: Complementation analysis was suitable for all FA patients with MMC-sensitive lymphoblastic cell lines, but this method is time consuming. Immunoprecipitation and Western blot are much faster for subtyping but could only be used for FA patients whose related genes had been cloned and specific antibodies been developed.

B-Lymphocytes↗

[The mutation of anti-CD3 antibody (HIT3a) gene and its expression].

OBJECTIVE: To improve the expression of anti-CD(3) single chain Fv (scFv) by site mutation and identify its biological activity. METHODS: Anti-CD(3) scFv gene was mutated by PCR, the target clones were screened by both the fingerprints of DNA restriction endonuclease digestion and Western blot, the antigen-binding activity of scFv was examined by FACS, competitive inhibition was performed with (125)I-labeled HIT3a and the cytotoxic effect mediated by the anti-CD(3) scFv-activated T lymphocytes was analyzed by (51)Cr-released assays. RESULTS: The DNA sequencing showed that the 6th amino acid of the anti-CD(3) antibody (HIT3a) heavy chain gene was mutated from E (GAG) to Q (CAG). The expression of mutated anti-CD(3) scFv (m2) was increased by 100 times higher than that of the parent scFv, and there was no difference in the Jurkat cell (CD(3)(+))-binding activity between the (m2) and parent scFv. The preliminary results of competitive assays showed that m2 could partially block the sites of CD(3)(+) Jurkat cells where the parent antibody bound to. Cytotoxicity assays demonstrated that CD(3)AK cells induced by IL-2 and m2 showed stronger cytotoxic effect than that of LAK cells induced by IL-2 alone in vitro. CONCLUSION: By site mutation, a high expression fragment m2 of anti-CD(3) scFv antibody was obtained. The results of some experiments indicated that m2 could bind to CD(3)(+) Jurkat cells, furthermore, by co-stimulated with IL-2, it could activate peripheral T lymphocytes and induce CD(3)AK cytotoxic effect.

CD3 Complex↗

[Intracellular potential changes in crucian carps Mauthner cells evoked by vagal sensory inputs].

In the present experiments, microelectrode recording technique was used to explore the electrophysiological properties of Mauthner cells (M-cells) with stimuli applied to the right vagus. Direct stimulation of the right vagus evoked short-latency, long-lasting, graded, and complex postsynaptic potentials (PSPs) on both Mauthner cell bodies in crucian carp, which are stimulus strength- and frequency- dependent. The evoked PSPs reduced the amplitudes of the antidromic action potentials. After intramuscular injection of strychnine, both amplitude and averaged duration of the PSPs increased, on which two or more action potentials were superimposed. The results suggest that the afferent pathways from vagus to M-cells are mediated by several neuron chains with different numbers of relayed synapses, and they may be excitatory and/or inhibitory in nature. Therefore vagus input would modulate the excitability of the M-cells.

Action Potentials↗

[Effect of iron deficiency anemia on the reproduction of female rats and the development of their offspring].

The effects of iron deficiency anemia(IDA) on the reproduction of female rats and the development of their offspring were studied. Four-week-old female Wistar rats were randomly divided into two groups. The rats in experimental group and control group were fed on low iron or normal diet respectively for 14 weeks, and then they were mated with normal adult male rats. The development and growth of the newborn, weanling and four-day-old offspring was observed and the trace element Fe, Zn, Cu, Mn and Se in serum were measured. IDA made notable impacts on the reproduction of female rats with small sized litters, less living fetal rats. The survival rate of female rats in the IDA group was less than that in control group. Hemoglobin and packed cell volume in blood were lower in IDA group than those in control group(P < 0.0001). The content of serum Fe and Cu in IDA group was also lower than that in control group. Iron deficiency might cause metabolism disorders of other trace element.

Anemia, Iron-Deficiency↗

[Molecular cloning and expression in E. coli of the surface-exposed lipoprotein LipL41 gene of Leptospira lai].

OBJECTIVE: To construct a recombinant expressive plasmid using LipL41 gene of leptospira lai for further research of subunit vaccine of leptospira. METHODS: A pair of oligonucleotide primers were designed based on the sequence of LipL41 of leptospira kirschneri RM 52 in Genbank. With genomic DNA of leptospira lai 017 as template, a fragment was amplified by PCR and DNA sequencing analysis showed this fragment to be the gene that encodes LipL41. A recombinant vector was constructed using plasmid pGEX1 lambda T and the expression of LipL41 gene was tested. RESULTS: The production of PCR was LipL41 gene. The recombinant plasmid was constructed and testified by nuclease digestion and PCR, and LipL41 gene could express in E. coli. CONCLUSION: The recombinant plasmid has been constructed successfully and LipL41 gene can express stably at high level.

Bacterial Outer Membrane Proteins↗

[A possible criteria for diagnosis of early caries in pits and fissures].

OBJECTIVE: The aim of this study was to examine pits and fissures of occlusal surfaces with severe stains by both histological and clinical methods, and to evaluate the criteria for diagnosis of early caries in pits and fissures. METHODS: Thirty-one fresh extracted molars and premolars, severely stained but no detectable defects in the surfaces, walls and floors of occlusal fissures, were collected. The teeth were longitudinally sliced across the stained fissures and ground into sections of 100-140 microns. The sections were observed using microscopy and microradiography. RESULTS: All samples showed early carious lesions in pits and fissures under microscope. Demineralization in walls or floors was identified by microradiography in 30 samples. CONCLUSION: Although without detectable defects, severely stained pits and fissures showed demineralization by using microscopy and microradiography. Thus, early caries in pits and fissures may be identified by the severely stained appearance.

Adolescent↗

[Changes of soft tissue profile in operated unilateral cleft lip and palate patients after maxillary protraction].

OBJECTIVE: The aim of this study is to investigate effects of maxillary protraction on soft tissue profile in operated operated unilateral cleft lip and palate (UCLP) patients. METHODS: A total of 10 growing UCLP patients (male 7, female 3), age from 8.2 to 12 years old (Average: 10.4 years old), were selected to be treated with maxillary protraction using head gear-chin cap-long hook protraction appliance. The appliance was worn 12-14 hours per day, and the protraction force was 400-500 g each side. The protraction direction was forward and slightly downward. The treatment period was 4.7 months (Average: 5.8 months). Cephalometrics were taken before and after treatment. The changes of soft-tissue profile were studied using the computer-aid X-ray cephalometric analysis. RESULTS: After protraction, the points of Prn, Sn and Ls moved forward significantly. The distance from points Ls to E plane changed significantly from 0.46 mm before treatment to 1.18 mm after treatment. The angle G-Prn-Pg' decreased significantly, and G-Sn-Pg' changed significantly from -0.30 before treatment to 6.260 after treatment. The anterior-posterior position of mandible and lower lip did not change significantly, the changes of angles Cm-Sn-Ls, A'ls/SiLi had no statistical significance. The results indicated that maxillary protraction could make maxilla and upper lip move forward, and the convexity of soft tissue profile improve significantly. CONCLUSION: Maxillary protraction is an effective way to improve the facial deformity of operated UCLP patients. UCLP patients should have early interrupted treatment.

Cephalometry↗

[Cloning and efficient expression of cytokine human MK in E. coli].

For cloning the cytokine human Midkine (MK) gene, we designed by PCgene program and synthesized a pair of PCR specific primers according to the reported human MK cDNA sequence. Total cellular RNA was extracted from a human hepatoblastoma cell line HepG2, and then the target DNA fragment was obtained by RT-PCR and subcloned into plasmid pUC118. Checked with radioisotope sequencing and ABI 377A sequencer, the nucleotide sequence of the cloned MK cDNA was identical with the reported one. A prokaryotic expression vector, named pBV220, was used to express the MK protein efficiently in E. coli strain TG1 and a predicted band of 16.5 kD in Mr by 15% SDS-PAGE was found. The expressed recombinant protein was found in insoluble aggregated form and accounted for about 31.21% of the total cellular proteins. The first 15 N-terminal amino acid sequence analysis of this protein by Edman degradation method showed that it was accordant with that predicted from the cDNA sequence. The activity of neurite outgrowth-promoting of the MK crude samples was tested with brain cells isolated from 18-day embryos of SD rat.

Animals↗

[Effect of cadmium on the phagocytic function of polymorphonuclear leukocyte in mice tested by chemiluminescence of whole blood].

The effect of cadmium chloride on the immunological toxicity of polymorphonuclear leukocyte (PMN) and on lipid peroxidation in liver were measured by using the chemiluminesence of whole blood and thiobarbituric acid (TBA) method. The results showed that 0.1 and 10 mmol/L of cadmium chloride could accelerate the chemiluminesence of whole blood in vitro, but 1000 mmol/L of cadmium chloride inhibit the chemiluminesence. Two hours after the injection of cadmium chloride through caudal vein, chemiluminesence of whole blood was induced obviously at the dose of cadmium 1 and 100 micrograms/kg BW in vivo, but the chemiluminesence was inhibited at the dose of 500 and 1000 micrograms/kg BW. At the dose of 1 microgram/kg BW, the peroxidation of liver lipids was induced. The results suggested that cadmium at low concentration accelerated the immunity of PMN, while high concentration was toxic to PMN, cadmium at low concentration could accelerate the phagocytic function of phagocytes. Phagocytosis brings about excessive active oxygen in organism and intensifies the action of active oxygen on the lipid peroxidation in tissue cells, at last, results in organic oxidation injury.

Animals↗

[DNA sequence analysis and expression of the recombinant plasmid pBX1 from Borrelia burgdorferi B31 strain].

OBJECTIVE: This study was to provide the target antigen for the development of a Lyme disease vaccine and serodiagnosis reagent. METHODS: We used the automatic DNA sequencing machine (Model 377) to detect the nucleotide sequence of the inserted part of the recombinant plasmid pBX1 from Borrelia burgdorferi B31 strain. The restriction enzyme map of the inserted part of pBX1 was analysed by using computer software. The expressed product of pBX1 in E. coli XLI-Blue MRF was analysed by using SDS-PAGE and western-blotting. RESULTS: 1. DNA sequencing showed that pBX1 contained a 477bp inserted gene fragment, and when it was compared with the published sequence of the specific region of the gene of the 83 kd antigen protein from Borrelia burgdorferi B31 strain, only one amino acid codon was different. 2. The restriction enzyme map of the inserted part of pBX1 was successfully constructed. 3. The recombinant plasmid pBX1 expressed a 29 kd fusion protein in E. coli XL1-Blue MRF' after induced with IPTG. The recombinant fusion protein could be recongnized by rabbit polyclonal antiserum against Borrelia burgdorferi B31 strain. CONCLUSION: A recombinant plasmid which contains the gene fragment encoding the specific region of the 83 kd antigen protein from Borrelia burgdorferi B31 strain has been successfully constructed. The recombinant plasmid can stably express 29 kd fusion protein in E. coli XL1-Blue MRF'. These results could serve as a base of further studies on the usefulness of the fusion protein in serodiagnosis and vaccine for Lyme disease.

Animals↗