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Biomedical subjects

Y Yang

Publications and source records attributed to Y Yang.

At least 1,099 records · Page 61Linked to original sources
PubMed1996

[The effect of electroacupuncture on the discharge activity of temperature-sensitive neurons of preoptic-anterior hypothalamus in the rabbit treated by arginine vasopressin].

Arginine vasopressin (AVP) has been shown to have significant effects on the thermoregulation. The present experiments were to investigate the effect of electroacupuncture (EA) on the discharge activity of temperature-sensitive neurons of preoptic-anterior hypothalamus (PO-AH) in rabbits treated by AVP and arginine vasopressin monoclonal antibody (AVPMcAb). The results were as follows: (1) AVP could markedly promote the firing activity of EA on heat-sensitive neurons in PO-AH. (2) AVPMcAb could markedly reduce the effect of EA on temperature-sensitive neurons in PO-AH. Experimental results indicated that the mechanisms of EA on hypothermia might be related to AVP.

Animals↗
PubMed1996

Effect of verapamil on Ca2+ influx and CVB3-RNA replication in cultured neonatal rat heart cells infected with CVB3.

The effect of verapamil on Ca2+ influx across the myocardial plasma membrane and coxsackie virus B3 (CVB3) -RNA replication in cultured neonatal rat heart cells infected with CVB3 was investigated. It was found that the Ca2+ influx could be inhibited significantly (P < 0.01) by verapamil (1 mumol/L) after infection of heart cells for 48 h. However, when the cultured heart cells infected with CVB3 and treated with verapamil (1 mumol/L and 10 nmol/L) at the same time for 48 h, the amounts of CVB3-RNA in myocytes were significantly higher than that in infected control group (P < 0.05). These phenomena suggest that the increase of Ca2+ influx of cultured heart cells infected with CVB3 could be inhibited by some calcium antagonists, e.g. verapamil at the early stage. On the other hand, verapamil might accelerate viral replication in myocardium. Thus, although verapamil could be beneficial for decreasing the secondary Ca2+ damages and improve the myocardial electric activity, it isn't a sensible choice for therapy in early stage of virus infection with cardiac symptoms.

Animals↗
PubMed1996

[The regulation of the secretion of transforming growth factor-beta 1 by estrogen on ovarian cancer AO, 3AO cell lines and its relationship with cell proliferation].

OBJECTIVE: To investigate the regulatory effect of the secretion of transforming growth factor-beta 1 (TGF-beta 1) by estrogen on ovarian cancer AO, 3AO cell lines and on cell proliferation. METHOD: The secretion of TGF-beta 1 was investigated by using western dot blot and the cell proliferation by 3H-thymidine uptake. RESULT: In vitro, AO cells under the effect of estrogen can secreted TGF-beta 1, and there was cell proliferation, but both gave dose-dependent responses. Estrogen significantly promoted the secretion of TGF-beta 1 of AO cells at low (10(-13) mol/L) and high (10(-5)mol/L) concentrations, but the level of cell proliferation showed inhibition. In contrast, in the 3AO cells under the same conditions, no difference in TGF-beta 1 secretion was found from those of the control groups, dose-dependent response was seen in cell proliferation and there was no significant correlation between the expression of TGF-beta 1 and cellular proliferation. CONCLUSION: The results suggest that there may be TGF-beta 1 autocrine loop in AO ovarian cancer cell line, which, when estrogen regulated may be associated with the cell proliferation. In 3AO cell line, under the same conditions, TGF-beta 1, autocrine is not regulated by estrogen, nor is it related to cell proliferation regulation.

Cell Division↗
PubMed1996

[Identification of the origin of 7q+ marker chromosome in a mental retard patient].

The present chromosome-specific and chromosome-band-specific probe pools constructed by the technique of human chromosome microdissection and PCR were taken as painting probes. Using the forward chromosome painting and chromosome screening method, we had identified a chromosome additional fragment of a 7 q+ marker chromosome in a patient originated from 3 q 26-->3 qter, and ascertained the patient's karyotype was 46, XX, -7, + der (7) t (7;3) (7 pter-->7 q 32::3 q 26-->3 qter). Applying this strategy, we can identify the origin of marker chromosomes fastly and effectively.

Child↗
PubMed1996

[Lobectomy by video-assisted thoracoscopic surgery].

Lobectomy by video-assisted thoracoscopic surgery (VATS) has been marked by decrease in pain, morbility, hospital stay, bleeding, and transfusion. This new way approach was performed on 10 dogs and 21 patients. In this paper we discuss how to deal with pulmonary vessels, bronchus and fissure. We suggested that Stage I lung cancer and lung disease were indicated of lobectomy by VATS.

Adolescent↗
PubMed1996

[Research on the recombinant plasmid pDJH2 of L. interrogans serovar lai: sequencing and alignment with other known bacterial Omp sequence].

The Leptospira whole cell vaccine (LWCV) currently used in China is safe and effective, out the immunity following vaccination with two doses of the fluid medium vaccine is of low order. The duration of immunity conferred by this vaccine is rather short, six months or at most one year. Therefore, it is necessary to develop new generation vaccines against Leptospirosis for the developing world. In this paper we report the sequencing of the insert fragment of pDJH2 from genomic DNA of L. interrogans sevovar lai strain 017 and its alignment with other bacterial omp sequences. A genomic library of Leptospira interrogaans serovar lai strain 017 was constructed with the plasmid vector pUC18. A recombinant plasmid designated pJDH2 was screened from the genomic library. Inserted fragment of pDH2 is 1.9 kb by gel electrophoresis. Immunization/protection was studied in BALB/c mice model. The results showed highly significant difference between pDJH2 and pUC18 (control). Inserted fragment of pDJH2 DNA sequencing was performed by Dr Yan Zhengxin (Max-Planck-Institut for Biology. Tubingen, Germany). Insert fragment was cloned into pBluescript II KS-(stratagene) and sequenced by using AB1 (Applied Bio Systems, Model 373A). Two open reading frames of 565 and 662 nucleotides were identified. There were identifiable initiation codons, terminators, Shine-Dalgano ribosome combining site, Pribnow boxes and Sextama boxes within the 2 sequenced regions. Nucleotide sequences were analysed using Gene Work, a suit of computer program developed by Department of Biochemistry St. Jude Children's Research Hospital Memphis. U.S.A. The results of formatted alignment showed the predicted nucleotide sequence of ORF1 of the serovar lai had significant similarity with ORF2 (49.36%). L. kirschneri ompL1 (49.26%), Borrelia burgdoferi omp (48.97%), Treponema phagedenis omp (47.3%); Salmonella typhimurium ompC(46.87%), Yersinia enterocolitica ompH (46.7%), Leptospira borgpeterseni pfap (46.3%), and Serratia marcescens omp (43.3%). The close relationship of the pDJH2 ORF1 and ORF2 nucleotide sequences from Leptospira kirschneri ompL 1 is apparent. Whether the recombinant pDJH2 will prove useful for vaccine development remains to be tested.

Animals↗
PubMed1996

[Subclones of fragment DNA recombinant rpDJH2 of L. interrogans serovar lai strain 017 and it's expression of high level in E. coli].

Fragment of 1.9 kb recombinant DNA of pDJH2 was linked with vectors pT7-7 and pRSETs. Then they were transformed into E. coli JM109 (DE3) respectively. Expression of subclones was achieved in E. coli JM109 (DE3) with IPTG inducement. SDS-PAGE showed that the molecular weights of products were 68kd and 23 kd respectively. The amount of production seemed to be higher than that of the outer membrane proteins of L. interrogans serovar strain 017 in nature. Immunoblotting of pDJt and pDJrB2 (both are subclones) with the specific antiserum of anti-OMP of L. interrogans serovar lai strain 017 and the experiment of initiative immuno-protection in guinea pigs showed both protein-68 kd and 23 kd might be the antigens of immuno-protection on the outer membrane of L. interrogans serovar lai strain 017.

Animals↗
PubMed1996

[Experimental study on repair of mandibular defect by allogenic decalcified bone compounded with autogeneic bone marrow in rabbits].

Twenty adult rabbits were used in our experiment. The bone defects were made at the lower border of the bilateral mandible. A compound bone graft (allogenic decalcified bone with autogeneic bone marrow, ADB) was implanted in the right bone defect as the experimental group. The left mandible was taken as the control group and autogeneic cancellous bone was grafted. The process of new bone formation was evaluated by X-ray plain film, 99Tc-PYP Scintigraphy, histological, and histochemical, and transmmission electronic microscope examinations. The results demonstrated histogically that ADB induced new bone formation. The quantity of new bone produced by compound bone graft in the experimental group was much more than that in control group (P < 0.05). The compound bone graft can promote and accelerate bone defect healing.

Animals↗
PubMed1996

[Diagnosis and surgical management of pancreatic pseudocysts].

Fifty-two patients with pancreatic pseudocysts were treated surgically between 1968 and 1994. Clinical symptoms were non-specific. Ten patients with acute pancreatitis were managed conservatively and resolution occurred in 3 patients. 42 patients underwent operation. Internal drainage was performed in 28 patients, external drainage in 8, others in 6. Pancreatic fistulas occurred in the external drainage group, 2 patients died and 1 patient had the of recurred pseudocyst. There were no complications in the internal drainage group. It was quite different in the external drainage group. The management should differ in that acute and chronic pancreatic pseudocysts. Patients with pseudocysts of chronic pancreatitis could undergo emergent surgery of internal drainage because waiting 6 weeks for maturation of the pseudocysts after diagnosis was unnecessary and even hazardous. However, if pseudocyst developed after acute pancreatitis, it should be watched for up to 6-8 weeks. During this period the pseudocyst perhap disappeared spontanously or matured for surgery.

Adolescent↗
PubMed1996

Cloning and expression of full-length delta-endotoxin cryIA(c) gene in three kinds of prokaryotic systems using shuttle vector pHT3101.

Two fragments, 6.5kb and 4.3kb encoding 5' end and 3' end of delta-endotoxin cryIA(c) gene, respectively, were selected from the Bacillus thuringiensis kurstaki-HD-73 75kb plasmid gene pool using random primer labelling delta-endotoxin cryIA(b) gene probe. The full-length 3.92kb cryIA(c) gene including 5' end 152 bp promoter sequence and 3' end 198 bp terminater sequence was rebuilt after uncoding sequences were deleted. Three kinds of engineering strains harbouring the same recombinant plasmid pHTY1 were obtained after the cryIA(c) gene had been subcloned in shuttle vector pHT3101 and transformed to E. coli NM522, Bacillus subtilis AS1176 and Bacillus thuringiensis crystal-deficient 4D10(H3ab). SDS-PAGE electrophoresis patterns reveal that the cryIA(c) gene expressed the same 133,300 protoxin proteins in all three host systems with the same molecular weight to the crystal protein from the Bacillus thuringiensis kurstaki HD-73. Immuno-assays indicate that the expression proteins can react with antiserum of HD-73 paraspore crystal protein in the same pattern as the natural crystalprotein. Bioassays using crude expressed products from three host strains reveal that they all showed toxicities to second instar larvae of Plutella xylostella, and their LD50 were calculated to be 0.311 micrograms/cm2, 0.02 micrograms/cm2 and 0.017 micrograms/cm2, respectively.

Bacillus subtilis↗
PubMed1996

Expression of BAGE, GAGE, and MAGE genes in human gastric carcinoma.

The MAGE, BAGE, and GAGE genes code for distinct antigens that are recognized by autologous cytolytic T lymphocytes. We investigated the expression of these genes in both cell lines and surgical samples of gastric carcinoma, using reverse transcription-PCR. Furthermore, the induction of these genes by 5-aza-2'-deoxycytidine (DAC), a demethylating agent, was also examined in several cell lines. Of 11 cell lines, BAGE, GAGE1-6, GAGE1-2, MAGE-1, and MAGE-3 were detected in 7 (64%), 4 (36%), 3 (27%), 8 (73%), and 8 (73%) cell lines, respectively. After the in vitro treatment of the negative cell lines with DAC, the expression of these genes became positive in 46 to 91% of these cell lines. No expression of these genes was seen in any of the 57 samples of normal gastric tissue. In contrast, the tumor tissue samples expressed BAGE, GAGE1-6, GAGE1-2, MAGE-1, and MAGE-3 in 13 (23%), 9 (16%), 6 (11%), 25 (44%), and 23 (40%) tissue samples, respectively. Thus, at least one of these genes was expressed in 35 (61%) of 57 carcinomas. An analysis of the relationship between clinicopathological factors and the expression of these genes revealed that either BAGE or one of these genes was more frequently expressed in histologically intestinal-type than in diffuse-type carcinomas. Our results suggest that, because of the higher expression of these genes and the possible induction of these genes by DAC, patients with gastric carcinoma may, therefore, be potential candidates for tumor-specific immunotherapy directed against these antigens.

Aged↗
PubMed1995

In vivo assembly of the proteasomal complexes, implications for antigen processing.

The multicatalytic and multisubunit proteasomal complexes have been implicated in the processing of antigens to peptides presented by class I major histocompatibility complex molecules. Two structural complexes of this proteinase, 20 S and 26 S proteasomes, have been isolated from cells. By analyzing in vivo assembly of the proteasomal complexes we show that the 20 S proteasomal complexes are irreversibly assembled via 15 S assembly intermediates containing unprocessed beta-type subunits. The 20 S proteasomes further associate reversibly with proteasome activators PA28 or pre-existing ATPase complexes to form 26 S proteasomal complexes. Our findings that not all of the 20 S proteasomal complexes are assembled into 26 S proteasomal complexes within cells and that all of PA28 and ATPase complexes are associated with 20 S proteasomes strongly suggest that all proteasomal complexes coexist within cells. We further demonstrate that 26 S proteasomal complexes are predominantly present in the cytoplasm and a significant portion of the 20 S proteasomal complexes is associated with the endoplasmic reticulum membrane. Taken together, our findings suggest that depending upon their associated regulatory components, 26 S and 20 S-PA28 proteasomal complexes serve different housekeeping functions within the cells, while they degrade antigens in a cooperative manner in antigen processing.

Animals↗
PubMed1995

Human CD8 transgene regulation of HLA recognition by murine T cells.

A series of human CD8 transgenic (hCD8 Tg) mice with differential expression in the thymus and periphery were produced to investigate CD8 coreceptor regulation of repertoire selection and T cell responses. Expression of hCD8 markedly enhanced responses to both HLA class I molecules and hybrid A2/Kb molecules providing functional evidence for a second interaction site, outside of the alpha 3 domain, which is essential for optimal coreceptor function. Peripheral T cell expression of hCD8 was sufficient to augment responsiveness to HLA class I, as hCD8 Tg mice which lacked thymic expression responded as well as mice expressing hCD8 in the thymus and periphery. Both murine CD8+ and CD4+ T cells expressing hCD8 transgenes exhibited markedly enhanced responses to foreign HLA class I, revealing the ability of T cell receptor repertoires selected on either murine class I or class II to recognize human class I major histocompatibility complex (MHC). In contrast to recognition of foreign class I, thymic expression of hCD8 transgenes was absolutely required to enhance recognition of antigenic peptide restricted by self-HLA class I. Thus, our studies revealed disparate requirements for CD8 coreceptor expression in the thymus for selection of a T cell repertoire responsive to foreign MHC and to antigenic peptides bound to self-MHC, providing a novel demonstration of positive selection that is dependent on human CD8.

Amino Acid Sequence↗
PubMed1995

Clearance of adenovirus-infected hepatocytes by MHC class I-restricted CD4+ CTLs in vivo.

E1-deleted recombinant adenoviruses have been developed for liver-directed gene therapy because efficient gene transfer to hepatocytes can be achieved in vivo. However, these viruses also express viral proteins in hepatocytes, leading to the development of destructive immune responses. Our previous studies indicated that MHC class I-restricted C D8+CTLs are major effectors in eliminating virus-infected cells, and CD4+ cells are also necessary in developing a fully competent CTL response by secretion of IFN-gamma, which sensitizes the virus-infected hepatocytes to CTLs through up-regulation of MHC class I expression. In this study, we have used adoptive transfer techniques in combination with mice deficient in immune functions to further define the role of CD4+ cells in the primary response to adenovirus-mediated gene transfer to the liver. Our studies indicate that CD4+ cells alone are capable of destroying virus-infected hepatocytes. Adoptive transfer experiments with beta 2m- mice along with in vitro CTL assays suggest that these CD4+ can act as CTL effectors, which are MHC class I-restricted. Depletion of these CD4+ effectors in vivo leads to prolongation of adenovirus-mediated transgene expression in hepatocytes. These results suggest that class I-restricted CD4+ CTLs contribute to elimination of adenovirus-transduced hepatocytes and extend our understanding of functional importance of CD4+ cells in viral pathogenesis.

Adenoviridae↗
PubMed1995

Efficient inhibition of activation-induced Fas ligand up-regulation and T cell apoptosis by retinoids requires occupancy of both retinoid X receptors and retinoic acid receptors.

Two retinoic acid (RA) receptors, retinoic acid receptors (RARs) and retinoid X receptors (RXRs), have been identified. All-trans-RA and its 9-cis-isomer are ligands for RARs, but only 9-cis-RA binds RXRs with high affinity. Activation-induced T cell hybridoma death is mediated via the engagement of Fas by activation-up-regulated Fas ligand, and RA prevents this type of apoptosis by inhibiting the induction of Fas ligand expression. To investigate the mechanism of RA action, T hybridoma cells were transfected with cDNA encoding RXR beta or dominant-negative RXR beta. Cells that overexpressed RXR beta were more sensitive to 9-cis-RA rescue from activation-induced death than cells transfected with vector alone. In contrast, cells expressing the dominant-negative RXR beta could not be rescued from death with 9-cis-RA. In wild type cells, an RAR-selective synthetic retinoid had little effect on activation-induced apoptosis, while an RXR-selective agonist prevented apoptosis but only at concentrations about approximately 10-fold greater than that required for 9-cis-RA. Simultaneous addition of the RAR- and RXR-selective retinoids completely prevented activation-induced apoptosis at concentrations where either alone had relatively little protective effect. The same hierarchy of efficacy was found for activation-induced Fas ligand expression. These data demonstrate that binding of both RARs and RXRs is required for efficient inhibition of activation-induced Fas ligand upregulation and T cell apoptosis by retinoic acid.

Animals↗