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Biomedical subjects

X Yu

Publications and source records attributed to X Yu.

At least 199 records · Page 11Linked to original sources
PubMed1999

Regulation of lymphocyte cell fate decisions and lymphomagenesis by BCL-6.

Genetic alterations of the BCL-6 gene in mice and man have established BCL-6 as a pivotal regulator of normal differentiation of B and T lymphocytes as well as one of the most frequently translocated oncogenes in human B cell lymphomas. As an oncogene, BCL-6 has not been easy to place into existing paradigms of cellular transformation. Rather, it is likely that the function of BCL-6 as a regulator of lymphocyte differentiation is subverted in BCL-6-induced lymphomas. The lymphomas in which BCL-6 is translocated are all suspected to arise from the germinal center B lymphocyte. Given the selective expression of BCL-6 protein in normal germinal center B lymphocytes and the requirement for BCL-6 in germinal center development, the functions of BCL-6 in normal and malignant B cells are probably intertwined. The BCL-6 protein is a potent transcriptional repressor which presumably controls lymphocyte differentiation and induces lymphomas by regulating the expression of key downstream target genes.

Animals↗
PubMed1999

Interstitial brachytherapy using iridium-192 for malignant brain tumors: clinical results.

OBJECTIVE: To determine the effects and toxicity of interstitial brachytherapy using iridium-192 on brain malignant gliomas. METHODS: Between January 1992 and January 1995, 56 patients with anaplastic astrocytoma and glioblastoma multiforme were treated with stereotactic brachytherapy using temporary high-activity iridium-192 sources. RESULTS: The median survival for patients receiving brachytherapy was 28 months. The survival rates at 1, 2, 3 years were 92.8%, 83.9% and 71.4% respectively. CONCLUSIONS: Brachytherapy may improve the control of local tumor and prolong the survival, when used in deep malignant brain gliomas, by temporary implanted high doses of iridium-192 sources.

Adult↗
PubMed1999

[Gene expression of beta-adrenoceptor signal transmitters in heart failure].

OBJECTIVE: To investigate the alteration in steady-state levels of messenger RNA(mRNA) of beta-adrenoceptor signal transmitters in heart failure. METHODS: The reverse transcription polymerase chain reaction (RT-PCR) was used to assess gene expression in small quantity of circulatory lymphocytes. With selected oligonucleotide primers, we used quantitative RT-PCR to amplify mRNAs encoding beta 2-adrenergic receptor(beta 2-AR), adenylate cyclase (AC), beta 2-adrenergic receptor kinase(beta-ARK), and beta-arrestin and cAMP response element binding protein (CREB) in 16 healthy subjects and 30 heart-failing patients. RESULTS: The alteration of gene expression in heart failure appeared to be selective, the steady-state levels of mRNA increased significantly involving AC and the transcription factor, CREB; decreased significantly involving membrane receptor, beta 2-AR; unchanged significantly involving phosphorylating factors of beta-AR uncoupling, beta-ARK and beta-arrestin. CONCLUSION: The aberrant gene expression of beta-adrenergic receptor might play an important role in the pathogenesis of heart failure.

Adenylyl Cyclases↗
PubMed1999

Immunological characteristics of natural resistance in Microtus fortis to infection with Schistosoma japonicum.

OBJECTIVE: To explore the immunological characteristics of natural resistance to Schistosoma japonicum infection in Microtus fortis (MF) living in the Dongting Lake area. METHODS: Passive transfer of sera from uninfected laboratory bred MF (BMF) to albinao mice (AM) was performed to observe the acquired protection. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme-linked immunoblotting (ELIB) methods were used to recognize 4 different life-cycle stage antigens of S. japonicum by sera from wild MF (WMF), BMF, BMF13 and BMF19. Tests were also performed on in vitro killing effect of sera and/or lymphocytes from BMF and WMF to schistosomulae; quantitative determination of C3 and C4 by immunoturbidometry, and interleukin-4 (IL-4) and antibodies to the 4 stage antigens in sera from WMF, BMF and infected BMF by ELISA. RESULTS: Compared with the control group, stool eggs per gram (EPG) of AM in the test group was significantly reduced by 81.54%, miracidium hatching rate, by 50.67%, liver egg counts, by 72.07%, the diameter of hepatic egg granuloma, by 70.39 microns. Western blotting probed with the 4 MF sera all revealed 7 specific bands for SSA, 3 for AWA and SEA, but none for CA antigens. The sera and/or lymphocytes from WMF and BMF gave obvious killing effects on schistosomulae with an adjusted death rate of 64.12%-78.83%. The levels of "natural antibodies" produced by MF to S. japonicum were in the following order: anti-SSA > anti-AWA > anti-SEA > anti-CA, all of which increased significantly after the infection. Serum levels of C3, C4 and IL-4 in uninfected BMF were significantly higher than those in AM. After infection, levels of C3 and C4 were further increased respectively by 72.83% and 295.49% in the 4th week and IL-4 by 303.83% in the 9th day. CONCLUSIONS: Immunological characteristics of innate resistance in M. fortis to S. japonicum infection were existed with no significant difference between WMF and BMF.

Animals↗
PubMed1999

[DNA polymorphism of Vibrio cholera and other vibrios].

OBJECTIVE: To investigate the inherent characteristics of V. cholera and other vibrios and the association between them. METHODS: Polymerase chain reaction (PCR), DNA sequences analysis, randomly amplified polymorphic DNA (RAPD) and average linkage cluster analysis were used to study V. cholera including 3 strains of O139, 4 strains of E1 Tor biotype, 3 strains of classical and 3 other vibrios. RESULTS: V. cholera O139 contained the genomic sequences of CTX A2-B as well as O1 V. cholera, indicating that their homologous nucleotides was 96.9%-98.7%, and other vibrios did not contain CTX. O1 V. cholera and other vibrios were divided into 4 groups by RAPD: classical; O139 and E1 Tor; V. paraheamolyticus and V. vulnificus; and V. flluvialis. The O139 DNA fingerprints of RAPD were almost as same as E1 Tor biotype, whose average linkage cluster distance was 0, similar with classical biotype, whose average linkage cluster distance was 2.07, much different from V. paraheamolyticus and others with the average linkage cluster distance being 6.76-8.54. CONCLUSION: V. cholera and other vibrios are polymorphic in inherent characteristics. Being as same as the inherent characteristics of E1 Tor, O139 may evoluted from E1 Tor biotype. And also the inherent characteristics of V. parahemolytisus were as same as those of V. vulnificus.

DNA, Bacterial↗
PubMed1999

[Influence of flavonoid of Astragalus membranaceus's stem and leaves on the function of cell mediated immunity in mice].

OBJECTIVE: To investigate the immune regulation of flavonoid of Astragalus membranaceus's stem and leaves (FAM). METHODS: Changes of total T cell count and subsets in mice were determined by monoclonal antibody assay before and after treatment with FAM, and the LAK activity was tested simultaneously by isotope technique. RESULTS: FAM could promote the proliferation of lymphocytes induced by ConA, raise the T cell count and regulate the T cell subsets disorder, elevate the LAK activity induced by IL-2. CONCLUSION: FAM possesses the effect of immune stimulation and immune regulation in treating immunosuppressive mice. This study provides the experimental basis for clinical application of FAM.

Adjuvants, Immunologic↗
PubMed1999

[Effect of ginseng injection in treating congestive heart failure and its influence on thyroid hormones].

OBJECTIVE: To observe the effect of Ginseng injection on congestive heart failure (CHF) and its influence on thyroid hormones. METHODS: Fifty-four Patients of CHF were divided into two groups. On the basis of conventional treatment of western medicine, the Ginseng injection was given to the treated group additionally. Blood level of triiodothyronine (T3), thyroxine (T4), reverse triiodothyronine (rT3) and thyroid stimulating hormone (TSH) of all patients were determined before and after treatment by radioimmunoassay. RESULTS: There were significant difference between the treated group and the control group in cure rate and mean course of therapy. The levels of T3 and T4 of all patients were lower than those of the normal control before treatment, and rT3 were higher. Two weeks after treatment, T3 and T4 level in all patients increased significantly and rT3 level significantly decreased(P < 0.05, P < 0.01). CONCLUSION: Ginseng injection has a good effect on patients with CHF. It also has regulatory effect on thyroid hormones.

Adult↗
PubMed1999

[Effects of humic acid on lipid peroxidation in arsenosis prevalent areas].

OBJECTIVE: To explore the causes of blackfoot disease in Taiwan. METHODS: Experiments to induce lipid peroxidation by arsenic and humic acid were made in vitro. Arsenic was determined for the water sampled from the arsenosis prevalent areas in Inner Mongolia and blackfoot disease prevalent areas in Taiwan and humic acid determined for the extracts of the coal rich in arsenic sampled from Guizhou Province in China by MDA-TBA colorimetry. RESULTS: Experiments found that humic acid could induce lipid peroxidation caused by sodium salt of unsaturated fatty acids in vitro in a weak and unstable manner, which could be promoted by 0.05 mmol/L of Fe(+ +) and not by 1 mmol/L As(2)O(3). The extent of lipid peroxidation caused depended on the sources, constituents and structure of humic acid samples, those from Inner Mongolia ranked the highest, those from Guizhou and Taiwan the medium and the commercial humic acid (Aldrich Co. in the US) the lowest. The experiments also found that lipid peroxidation caused by commercial humic acid presented a dynamic process in the existence of trace amount of iron, and humic acid could decompose the products of lipid peroxidation. CONCLUSION: The experiments suggested the relations of humic acid and arsenic to iron and other transition elements in the blackfoot disease prevalent areas and areas with an environment rich in arsenic and humic acid.

Arsenic Poisoning↗
PubMed1999

[Electroencephalography and transcranial Doppler analysis in children with migraine].

Electroencephalogram(EEG) and transcranial Doppler(TCD) recordings were carried out in 25 children with migraine during ictal and interictal period. The results were that the abnormal rate of EEG and TCD was 85% and 72%, respectively; the positive rate of EEG provoked test was 60%; there was the single untypical epileptiform wave in the occipital in 3 patients by EEG. We conclude that EEG combined TCD examination in migraine can increase the correct rate of diagnosis and help to differ epilepsy from migraine.

Adolescent↗
PubMed1999

[Effects of microwave acute irradiation on biomechanic properties of rabbit tissues].

The rabbit body was irradiated acutely by 2.45 GHz continuous microwave. After irradiation, the values of blood viscosity, blood viscoelasticity, platelet aggregation, erythrocyte fragility, erythrocyte deformation, erythrocyte aggregation, the compressive mechanic property and flexible property of bones were tested. The data of irradiated group and unirradiated group were compared. The results showed: after microwave irradiation, the rabbit blood viscosity and viscoelasticity decreased; the rabbit platelet aggregation rate decreased and the disaggregation rate increased; the erythrocyte fragility increased; the biomechanic properties of bones did not change considerably.

Animals↗
PubMed1999

[Computer-aided legal medical examination of body surface].

This paper provides a package of automatic and semi-automatic methods for computing the area of different kinds of body surface injuries. Compared with traditional methods, these processes of examination are faster and the conclusions are more precise and objective. Also presented are the authors classify the items into many types by standards which are necessary to let computer draw conclusions automatically. This software is conducive to improvement in work efficiency and convenience for judicial supervision.

Algorithms↗
PubMed1999

[Studies on immune responses in mice to expressed products from CSP gene of Plasmodium falciparum FCC1/HN isolate].

AIM: To construct the eukaryotic expression system with pcDNA3-PfCSP/HeLa for CSP gene of Plasmodium falciparum, and to observe the immune responses in BALB/c mice induced by the expressed proteins. METHODS: The recombinant plasmid pcDNA3-PfCSP was transformed into mammalian cell line of human HeLa cells. The expressed protein was isolated and analyzed by SDS-PAGE and used for immunization of BALB/c mice by subcutaneous, intravenous or intraperitoneal administration, respectively. ELISA, Western blotting, T lymphocyte proliferation test, natural killer cell activity and CD4+ and CD8+ T cells detection were used for observation of the level of humoral and cellular immune responses. RESULTS: Immune sera strongly reacted with the expressed protein. The titer of the antibodies was up to 1:6,400 by ELISA. Western blotting analysis revealed a specific band at 38.3 kDa. The specific proliferative response with immunized BALB/c mice spleen cells was remarkablely higher than that with control ones. The ratio of CD4+ and CD8+ T cells and the NK cell activity were significantly higher in the immunization group than that in the control groups. CONCLUSION: The humoral and cell-mediated immune responses and elevated NKC activity to expressed products with the eukaryotic expression system can specifically be detected in BALB/c mice to generate, indicating that the expressed protein could enhance immune activity in mice.

Animals↗
PubMed1999

[Recombination and cloning of MSP1(19) and PfCMR of Plasmodium falciparum].

AIM: To construct a recombinant plasmid DNA encoding multiantigens of Plasmodium falciparum and to provide the requirements for DNA immunization. METHODS: Two oligonucleotide primers were designed to amplify MSP1(19), the purified PCR products were digested by Sal I + Xba I, and the recombinant plasmid pWR450-1/PfCMR was digested by EcoR I + Sal I to recover PfCMR gene. PfCMR and MSP1(19) gene fragments were linked and recombined with mammalian expression vector pcDNA3. RESULTS: The MSP1(19) gene fragment with about 363 base pairs were specifically amplified by using PCR technique. The positive recombinant pcDNA3-PfCMR-MSP1(19) (named pcDNA3-Pf8) was screened and identified by agarose gel electrophoresis, endonulease digestion and PCR technique, the whole length of Pf8 is 618 bp. CONCLUSION: By specifically amplifying MSP1(19) gene at the C-terminal of MSP1, a recombinant plasmid pcDNA3-Pf8 encoding multiantigens of Plasmodium falciparum was successfully constructed.

Animals↗
PubMed1999

[Preliminary study on the levels of natural antibodies against Schistosoma japonicum in Microtus fortis in Dongting lake area].

AIM: To explore the detection rate and the levels of natural antibodies to cercarial antigen(CA), juvenile antigen(JA), adult worm antigen (AWA) and soluble egg antigen (SEA), respectively, derived from Schistosoma japoncum in Microtus fortis distributed in Dongting Lake area. METHODS: The antibodies in wild Microtus fortis(WMF), laboratory-bred Microtus fortis (BMF) and laboratory-bred Microtus fortis 15 days after S. japonicum infection (BMFi15) were detected by indirect ELISA and a comparison of the antibody levels between Microtus fortis including WMF, BMF, BMFi15 and albino mice without infection (AM), 15 days after infection(AMi15) and 42 days after infection (AMi42) was made. RESULTS: The positive rates of detection for anti-JA-Ab in WMF and BMF were 94.6% and 94.4%, respectively, followed by 85.5% and 83.3% for anti-AWA-Ab, 58.1% and 59.4% for anti-SEA-Ab, and 14.3% and 13.9% for anti-CA-Ab. The levels of antibodies to the above four antigens in BMFi15 increased significantly, the detection rates being 100% for anti-JA-Ab and anti-AWA-Ab, 84.4% for anti-SEA-Ab and 65.6% for anti-CA-Ab. The levels of antibodies in WME, BMF and BMFi15 had the similar trend(JA > AWA > SEA > CA), and those in BMFi15 to CA, JA, AWA and SEA increased by 1.9, 2.2, 2.1 and 1.5 folds, respectively, when compared with BMF. CONCLUSION: Natural antibodies to Schistosoma japonicum were found in wild and labortorybred Microtus fortis. The levels of antibodies in BMFi15 to four above antigens were apparently higher than those in AMi15.

Animals↗
PubMed1999

[Taxonomic studies on Echinochasmus fujienensis and its related species by random amplified polymorphic DNA analysis and experimental infection].

AIM: To explore the identification and differentiation of Echinochasmus fujianensis, Echinochasmus japonicus(Jiangxi strain and Fujian strain), Echinochasmus liliputanus Anhui and Echinochasmus per foliatus Hubei. METHODS: Random amplified polymorphic DNA analysis (RAPD) and experimental animal infection were performed. RESULTS: 469 polymorphic DNA fragments were obtained by 28 primers from 4 Echinochasmus species and strains in Fujian, Anhui and Jiangxi. 20.8% and 97.6% of the fragments in Echinochasmus fujianensis were the same as those in Echinochasmus japonicus Fujian strain and in Echinochasmus liliputanus Anhui, respectively, 99.7% of the fragments were the same between Echinochasmus japonicus Jiangxi strain and Fujian strain. CONCLUSION: Echinochasmus fujianensis and Echinochasmus liliputanus Anhui are the same species. Echinochasmus fujienensis is an independent species different from Echinochasmus japonicus. Polyinfection of Echinochasmus fujianensis, Echinochasmus japonicus and Echinochasmus perfoliatus exist in all the 3 provinces, Hubei, Anbui and Fujian, of which Echinochasmus fujienensis is a dominant species.

Animals↗
PubMed1999

[Cloning and sequencing of the genes coding for the histidine-rich protein II of Plasmodium falciparum].

AIM: To compare and analyze the homology of genes encoding histidine-rich proteinII (HRPII) of different Plasmodium falciparum isolates. METHODS: Using PCR technique, the complete genes coding for HRPII of P. falciparum isolates FCC1/HN and VN isolates were amplified. PCR products were digested by HindIII/BamHI and cloned into plasmid pUC19. The recombinant plasmid HRPII/pUC19 was screened and identified by PCR and restriction analysis. The cloned HRPII genes were sequenced by Sanger's method. RESULTS: HRPII genes of FCC1/HN and VN isolates were successfully amplified and cloned into pUC19. DNA sequencing showed that the coding length of HRPII gene was 1,020 bp without introns in FCC1/HN and VN isolates, however, there were ten points mutations between them. FCC1/HN isolate exhibited 98.8%, 92.2% and 98.7% homology in amino acids with isolates VN, IMTM22, and Itg2, respectively. Though the numbers of repeat sequences were different in four isolates, they had the same hydrophobic leader sequence and a single putative glycosylation site. The secondary structure analysis showed that the main antigenic determinants of four isolates were located on 5' end non-repeat region (amino acids 1-60). CONCLUSION: FCC1/HN isolate was highly homologous in the coding region of HRPII with VN, IMTM22, and Itg2 isolate. Four isolates exhibited similar structural characteristics and antigenic determinants in HRPII.

Amino Acid Sequence↗