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Biomedical subjects

X Guo

Publications and source records attributed to X Guo.

At least 109 records · Page 6Linked to original sources
PubMed2001

[Design of multi-channel EEG collection system for stereoscopic VEP and study of the VEP evoked by binocular disparity].

A multi-channel EEG collection system has been constructed for visual evoked potentials (VEP) studies, using IBM compatible PC and clinical EEG amplifier. The collection system not only is suitable for investigative and clinical use, but also works perfectly in the EEG collection and signal processing of stereoscopic VEP. The characters of the depth related VEP evoked by binocular disparity were identified after analysing and comparing the VEP superposition results. The partial results of the VEP extraction are in accord with the previous studies. The system serves as a helpful tool in studies of stereoscopic cognition and brain function.

Adult↗
PubMed2001

Arsenic contamination of groundwater and prevalence of arsenical dermatosis in the Hetao plain area, Inner Mongolia, China.

An investigation was carried out on arsenic contamination of groundwater and prevalence of arsenical dermatosis in the Hetao plain of Inner Mongolia Autonomous Region, China. Based on the screening of water samples from 96 randomly selected wells in this Region, two areas (Wuyuan and Alashan) were chosen as highly contaminated areas because arsenic in the water samples was higher than 50 microg/l. Arsenic was measured using an arsenic silver diethyl dithiocarbamate method for 326 water samples from all the wells in these areas. The results show arsenic contaminated groundwater from tubule-type wells of depths about 15-30 m was serious compared with open-type wells where depth is about 3-5 m. In the Wuyuan area, 96.2% of water samples from tubule-type wells contained arsenic above 50 microg/l and 69.3% in Alashan area; the highest value was 1354 microg/l and 1088 microg/l, respectively. In these two areas, a health survey was carried out for arsenical dermatosis. The results show the prevalence of arsenical dermatosis in the Wuyuan area was 44.8%, higher than 37.1% prevalence of arsenical dermatosis in the Alashan area. The prevalence of arsenical dermatosis was highest in the over 40-year-old age group. There was no sex difference in the prevalence. Further investigation is needed to clarify the actual situation of arsenic pollution of groundwater in Inner Mongolia, China in order to reduce the adverse health effect among residents exposed to arsenic.

Adolescent↗
PubMed2001

Opposing effect of p38 CCDPK and p44/42 CCDPK signaling on TNF-alpha-induced apoptosis in bovine aortic endothelial cells.

AIM: To investigate the pro-apoptotic role of tumor necrosis factor alpha (TNF-alpha) in cultured bovine aortic endothelial cells (BAEC) and its underlied apoptotic signaling pathways. METHODS: BAEC were cultured and passaged in Dulbecco's modified Eagle's medium (DMEM). Morphologic changes and quantification of apoptotic cells were determined under fluorescence microscope after TNF-alpha treated BAEC for 24 h with Hoechst 33258 staining. Cell viability was determined with MTT method. DNA fragmentation was visualized by agarose gel electrophoresis. The expression of phospho-p38 and phospho-p44/42 Ca2+-calmodulin dependent protein kinase (CCDPK, formerly called MAPK) was measured by Western blotting. RESULTS: TNF-alpha elicited typical apoptotic morphologic changes (chromatic condensation, nucleus fragmentation) and DNA fragmentation. At 1000-5000 kU/L, incubation with TNF-alpha for 24 h induced BAEC apoptosis and both of phospho-p38 and phospho-p44/42 CCDPK expression in a concentration-dependent manner. Interestingly, TNF-alpha-stimulated activation of p44/42 CCDPK was completely blocked, TNF-alpha-induced apoptosis was markedly increased by preincubation with U0126, a specific p44/42 CCDPK inhibitor. However, SB203580, a specific p38 CCDPK inhibitor, completely blocked TNF-alpha-stimulated activation of p38 CCDPK, and enhanced the expression of phospho-p44/42 CCDPK induced by TNF-alpha, substantially inhibited the pro-apoptotic effect of TNF-alpha. CONCLUSION: TNF-alpha simultaneously activates p38 CCDPK and p44/42 CCDPK, and these two CCDPK signaling pathways appeared to play opposing roles in TNF-alpha-induced apoptosis in BAEC.

Animals↗
PubMed2001

Delivery of glucocorticoid conjugate in rat gastrointestinal tract and its treatment for ulcerative colitis.

AIM: To evaluate colonic delivery and therapeutic effect of the newly synthesized dexamethasone (DX)-dextran (500 000) conjugate (DXD50) in the rat. METHODS: The amount of dexamethasone was measured in the contents from different parts of rat gastrointestinal tract and in plasma after ig conjugate. Therapeutic effect of conjugate and DX was tested in trinitrobenzenesulfonic acid-induced colitis in rat. Repair of colitis was assessed by measuring colonic ulceration area, colon weight, and colonic myeloperoxidase (MPO) activity. Systemic immunosuppression of DX was evaluated with weight of thymus and spleen and lymphocyte count in peripheral blood from rat with ulcerative colitis. RESULTS: Dexamethasone released from conjugate was mainly distributed in contents of cecum and colon. When DXD50 and DX 0.25 micromol . kg-1 . d-1 were used ig to treat ulcerative colitis in rat, the ulcerative area of colon was reduced by 55.6 % and 33.3 %, respectively whereas colon weight was reduced by 17.9 % and 2.6 %, respectively. The conjugate had no effect on lymphocyte count in peripheral blood, spleen weight, and thymus weight of rat which could be reduced markedly by the same dose of DX (P < 0.05 vs control). CONCLUSION: DXD50, which could specifically deliver DX to large intestine, is a promising agent in the treatment of human inflammatory bowel disease.

Animals↗
PubMed2001

[Maintenance ration and conversion efficiency of Hyporhamphus sajori].

The maintenance ration and conversion efficiency of Japanese halfbeak, Hyporhamphus sajori were tested with enclosures installed in a shrimp raising pond. The results showed that there existed an evident relationship between daily ration(DR) and growth rate(GR) of the fish, GR = 140.37 DR - 24.03. The conversion efficiency was 13.96% in biomass or 16.12% in energy. The maintenance ration was 17.12% and 20.39% of body weight in terms of growth rate and specific growth rate, respectively, indicating that it could be deduced from growth rate quite differently from that from specific growth rate in the same experiment. The abnormal growth rate appeared when daily ration was below 3.30% of body weight, implied that Japanese halfbeak may get other food resources besides supplied net zooplankton.

Animals↗
PubMed2001

[Human factor VIII expression in retrovirus vector-transduced bone marrow stromal cells].

OBJECTIVE: To explore the feasibility of bone marrow stromal cells (BMSCs) used for gene therapy of hemophilia A. METHODS: Murine and rabbit BMSCs were transduced with a recombinant replication-incompetent retrovirus LNC-FVIII delta B, which encloses a B-domain-deleted (760aa-1,639aa) human factor VIII cDNA. An optimized protocol involving temperature declining (32 degrees C) and centrifugation was used. Antigen and coagulant activity of human FVIII in the cell culture medium were measured by ELISA assay and one-stage method, respectively. Semi-quantitative PCR was performed for the transduction efficiencies. Western blot was used for FVIII protein analysis. RESULTS: Transduction efficiencies were increased 5- to 8-fold by temperature decline and centrifugation, which resulted in high expression and secretion of FVIII in transduced mouse[(556 +/- 80) ng/10(6) cells/24 hr] and rabbit [480 +/- 56) ng/10(6) cells/24 hr] BMSCs. Coagulant activities of human FVIII secreted from transduced murine and rabbit BMSCs were 2.42 U/10(6) cells/24 hr and 1.8 U/10(6) cells/24 hr, respectively. Western blot analysis demonstrated that the B domain-deleted FVIII cDNA was secreted predominantly as heavy and light chain heterodimers that resemble the native forms in human plasma. CONCLUSIONS: It was demonstrated that the BMSCs system has potential utility in the gene therapy for hemophilia A.

Animals↗
PubMed2001

[Degradation of nitrobenzene in water by electrohydrodynamic DC discharge].

In this paper, the experimental results with respect to the degradation of nitrobenzene in water using electrohydrodynamic DC discharge were presented. The DC voltage was 40 kV, the degradation efficiency in the first discharge process reached 50%, the total degradation efficiency in the second discharge process reached 80%. The products contained acetone. At the same time, the degradation efficiency variation with the voltage polarity, flux, and concentration were studied. These studies will be helpful to the treatment of organic wastewater.

Electrolysis↗
PubMed2001

[Treatment of congenital jerky nystagmus with opposite bidirectional neutral zone].

OBJECTIVE: To explore a method for the treatment of congenital jerky nystagmus with opposite bidirectional neutral zones. METHOD: The relatively used side between the two neutral zone was found by neutralizing bilateral head torsion angle with prisms. The surgical intervention was indicated for those patients whose head position would not turn to another side. RESULT: There were 14 cases treated by this method, none of these cases whose head position turned to another side. Ten cases underwent once operation, 2 cases, twice operations and another 2 cases undertook once operation with additional prism correction. The compensatory head posture was corrected and the vision in the primary position of gaze was improved in all the cases. CONCLUSION: This therapy for congenital jerky nystagmus with opposite bidirectional neutral zone shows significant therapeutic effects and can be available for clinical application.

Adolescent↗
PubMed2001

[Penetrance of Leber hereditary optic neuropathy in Chinese individuals with mitochondrial DNA 11778 mutation].

OBJECTIVE: To analyze the penetrance of Leber hereditary optic neuropathy (LHON) in families with homoplasmic mitochondrial DNA (mtDNA) 11778 mutation. METHODS: Maternal relatives of 16 families were analyzed based on ocular phenotype and primary mtDNA mutation analysis. RESULTS: One hundred and thirty individuals from the 16 families harbored the 11778 mutation. Of the 130 individuals, 65 were male and 65 female. Forty-three individuals (34 male and 9 female) were affected with LHON. The penetrance of LHON in the 16 families ranged from 13.3% to 66.7%, with an average penetrance of 33.1%. Males, with an average penetrance of 52.3%, were more affected than females who had an average penetrance of 13.8%. About 79% of the affected individuals were male with a male to female ratio of 3.8: 1. The number of affected females found in the families analysis is greater than that in the probands analysis where only 3 of 41 probands with LHON and mtDNA11778 mutation were female(male to female ratio =12.7:1). CONCLUSION: The penetrance of LHON in Chinese individuals with homoplasmic mtDNA11778 mutation is about one third,which is within the range of that in Caucasion.

DNA Mutational Analysis↗
PubMed2001

High level expression of human factor VIII in mammalian cells after retroviral-mediated gene transfer.

OBJECTIVE: To develop a retroviral-mediated high efficient expression system of human coagulation factor VIII. METHODS: The LNC-FVIIIBD retroviral vector was generated by cloning a human B-domain-deleted (760aa-1639aa) Factor VIII (FVIII) cDNA (FVIII cDNA BD) into the retroviral vector pLNCX. Several mammalian cell lines, including NIH3T3, CHO, Cos-7 and human hepatic cell line, L-02, were transduced with viral supernatant from the highest virus-producing PA317 clone. Antigen and coagulant activity of human FVIII in cell culture medium were measured by ELISA and a one-stage method, respectively. RT-PCR was performed for the detection of FVIIIBD mRNA. RESULTS: Human FVIII was expressed in all four target cells, with the highest FVIII expression observed in NIH3T3. The coagulant activity of secreted FVIII was up to 1.6 U/10(6) cells.24 hrs-1, and the FVIII antigen was 500 ng/10(6) cells.24 hrs-1. FVIII coagulant activity and antigen expressed by transduced CHO cells were 0.12 U/10(6) cells.24 hrs-1 and 62.4 ng/10(6) cells.24 hrs-1, respectively. Human FVIII expression was relatively low in Cos-7 and L-02 cells. RT-PCR results demonstrated transcription of FVIII cDNA BD in the target cells. CONCLUSIONS: The constructed retroviral vector was able to direct high level expression of human FVIII in various mammalian cell lines. It has potential utility in the future gene therapy for Hemophilia A.

Animals↗
PubMed2001

[Significance of lung perfusion scanning with technetium labeled macroaggregated albumin and pulmonary function assay for diagnosis of early hepatopulmonary syndrome].

OBJECTIVE: To evaluate the values of pulmonary function assay and dynamic pulmonary perfusion imaging with technetium labeled macroaggregated albumin ((99m)TcMAA) in the early diagnosis of hepatopulmonary syndrome (HPS). METHODS: The pulmonary function assay and (99m)TcMAA scans were performed in 28 patients with HPS, 30 cirrhotic patients (CP) without HPS, and 21 healthy controls (HC). RESULTS: In the patients with HPS, PaO(2), SaO(2) and diffusion capacity for carbon monoxide of lungs (DLco) was significantly lower than that in CP (P<0.01) and HC (P<0.01), and alveolar-arterial gradient [P((A-a))O(2)] was significantly increased (P<0.001). Results from (99m)TcMAA scans showed that the radionuclides were distributed over the spleen, kidney, liver and brain, and the ratios of arterivenous shunt were significantly higher than that in CP (P<0.001) and NC (P<0.001). In cirrhotic patients, DLco significantly decreased (P<0.05), P((A-a))O(2) and shunt ratios increased (P<0.01 and 0.001). CONCLUSIONS: Pulmonary function assay and dynamic pulmonary perfusion imaging with (99m)TcMAA are sensitive methods for diagnosis of the early HPS.

Hepatopulmonary Syndrome↗
PubMed2001

[Expression of endometrial leukaemia inhibitory factor gene in patients with unexplained infertility].

OBJECTIVE: To investigate the expression of endometrial leukaemia inhibitory factor(LIF) gene in patients with unexplained infertility. METHODS: By a quantitative reverse transcription-polymerase chain reaction (RT-PCR), the expression of LIF gene on endometrium during mid-luteal phase was detected in 35 unexplained infertility (infertility group) cases and 20 infertile cases due to tubal obstruction or male factor (control group). RESULTS: The level of LIF mRNA expression on endometrium during mid-luteal phase in infertility group was 0.448 +/- 0.239, significantly lower than those in the control group (1.093 +/- 0.761, P < 0.01). CONCLUSIONS: Our findings suggested LIF might play an important role in the process of implantation. The decreased expression of LIF gene might be one of the major causes of unexplained infertility.

Embryo Implantation↗
PubMed2001

[Effects of leptin on estradiol and progesterone production by human luteinized granulosa cells in vitro].

OBJECTIVE: To investigate the effects of leptin on steroidogenesis of human luteinized granulosa cell in vitro. METHODS: Human luteinized granulosa cells were isolated from follicular fluid obtained during oocyte retrieval of in vitro fertilization-embryo transfer program and were cultured with M199 medium plus various concentration of leptin (0, 10, 30, 100, 300 ng/ml), human menopausal gonadotropin (hMG, 0, 0.1, 0.2, 0.5, 1, 2, 5, 10 IU/ml) and testosterone 100 micrograms/ml. For 2 days the media were collected for estradiol and progesterone measurements. RESULTS: Addition of leptin alone did not alter estradiol and progesterone production (P > 0.05) by human luteinized granulosa cells. Leptin of 10-30 ng/ml concentrations caused a dose-dependent inhibition of estradiol production (P < 0.05) while greater than 0.5 IU/ml of hMG were added. There was no effect of leptin on hMG-stimulated progesterone production (P > 0.05). CONCLUSION: Leptin can directly inhibit hMG-stimulated estradiol production by human luteinized granulosa cells in vitro, but has no effect on progesterone production. Leptin may play an important role in follicle development and luteinization.

Cells, Cultured↗
PubMed2001

Homocysteine induces expressions of adhesive molecules on leukocytes in whole blood.

OBJECTIVE: To observe whether homocysteine can directly alter the expressions of CD11b, CD18, CD14 and L-selectin on neutrophils, monocytes, and lymphocytes in whole blood from healthy human subjects. METHODS: Leukocyte surface adhesive molecule expressions were analyzed by immunofluorescence flow cytometry. RESULTS: Homocysteine at the lowest concentration (20 mumol/L) significantly increased surface adhesive molecule expressions of CD11b and CD18 on each cell type and CD14 on monocytes and neutrophils in whole blood. These effects were increased at homocysteine concentrations of 200 and 400 mumol/L, but at concentrations > or = 1 mmol/L, CD11b/CD18 and CD14 expressions on all types of leukocytes were decreased. L-selectin expression was slightly decreased on all cell types in whole blood by homocysteine. CONCLUSION: Homocysteine alters leukocyte expressions of CD11b/CD18, CD14 and L-selectin on leukocytes, which may be involved into homocysteine-induced leukocyte adhesion and migration.

Adult↗
PubMed2001

[A study of mutation(s) of the epithelial sodium channel gene in a Liddle's syndrome family].

OBJECTIVE: To study the genetic mechanism of Liddle's syndrome in a family and help the diagnosis (specially ante-natal) and treatment of Liddle's syndrome clinically. METHODS: (1) Physical examination and measurement of serum potassium, plasma aldosterone and renin activity respectively by biochemical and radioimmunological assays were made for the member of the family. (2) Venous blood samples were collected from the members of the family and total genomic DNA was prepared. One set of specific primers was used for direct polymerase chain reaction, for amplifying C terminus of beta-subunit of epithelial sodium channel (hbetaENaC). Polymerase chain reaction products were subjected to single-strand conformation polymorphism and direct DNA sequence analysis. RESULTS: A new frameshift mutation (1bp, INS, 600G) of the gene of C terminus of beta-subunit of hbetaENaC was found in the Liddle's syndrome family. This mutation introduced a new stop codon at position 605 and deleted the last 34 normal amino acids from the C teminus of hbeta ENaC. Eight genetically affected subjects had severe hypertension and suppressed levels of plasma aldosterone and plasma renin activity; half of them had hypokalemia. CONCLUSION: The frameshift mutation (1bp, INS, 600G) of hbetaENaC gene is the likely cause of Liddle's syndrome in this Chinese family.

Adolescent↗
PubMed2001

[Association between asthma and the polymorphism of HLA-DQ genes].

OBJECTIVE: To investigate association between asthma and HLA-DQ genes in Chinese asthma family. METHODS: HLA genotyping was done for HLA-DQ using polymerase chain reaction-sequence specific primers (PCR-SSP) in 98 members of 32 Chinese asthma families and 67 normal controls. RESULTS: The allele frequencies of DQA1 * 0101 and DQA1 * 0601 in asthmatics (40.0% and 45.0% respectively) were significantly higher than those in normal controls (16.4% and 13.4% respectively; chi(2) = 6.1860, P < 0.05, RR = 3.39 and chi(2) = 11.609 0, P < 0.01, RR = 5.27 respectively). The allele frequencies of DQB1 * 0303 and DQB1 * 0601 in asthmatics (55.0% and 47.5% respectively) were also significantly higher than those in normal controls (13.7% and 13.7% respectively; chi(2) = 15.740 0, P < 0.01, RR = 7.68 and chi(2) = 10.930 0, P < 0.01, RR = 5.69 respectively). The allele frequency of DQ * 0201 (39.4%) was significantly higher in members with positive specific IgE response to dermatophagoides than that in non-atopy members (12.0%) in asthma family (t = 2.382 5, P < 0.05). CONCLUSION: HLA-DQA1* 0101, DQA1 * 0601 and HLA-DQB1 * 0303, DQB1 * 0601 may be the susceptible alleles of asthma. HLA-DQB1 * 0201 allele may limit the specific IgE response to dermatophagoides.

Adolescent↗
PubMed2001

[The engulfment effects of macrophage on apoptotic eosinophils treated by anti-Fas monoclonal antibody in vitro].

OBJECTIVE: Expression of the Fas antigen and induction of apoptosis in eosinophils (EOS) by anti-Fas antibody in vitro were investigated. METHODS: The purified EOS from healthy donors were cultured for 72 h in the presence of human IL-5 and with or without anti-Fas monoclonal antibody (MPhiAb) at various concentrations (1 approximately 1 000 ng/ml). The changes of eosinophil viability, percentage of apoptosis, and fragmented DNA electrophoresis were observed. The eosinophils treated by Fas MPhiAb for 24 h, 48 h, 72 h were cultured with monocyte-derived macrophages, the positive percentage of macrophages which engulfed EOS was calculated. RESULTS: The anti-Fas MoAb suppressed IL-5-mediated EOS survival in dose- and time-dependant manner. High concentration of IL-5 (10(6)U/L) could not inhibit anti-Fas MoAb-mediated apoptosis. The percentage of apoptosis was (35 +/- 6)% after 24 h treated with Fas MoAb (P < 0.01), and increased to (96 +/- 3)% after 72 h (P < 0.01). The percentage of macrophages which engulfed eosinophils was significantly higher than control (P < 0.01). CONCLUSION: The anti-Fas MoAb can efficiently induced eosinophils apoptosis, apoptotic EOS induced by anti-Fas MoAb could be engulfed by macrophages.

Antibodies, Monoclonal↗