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Biomedical subjects

R Wang

Publications and source records attributed to R Wang.

At least 451 records · Page 25Linked to original sources
PubMed1997

Surgical treatment of five hundred and thirty patients with early stage I and II stage cervical carcinoma.

OBJECTIVE: To investigate some problems in relation to the prognosis of surgical treatment of cervical carcinoma through analysing the clinical data of 530 patients. METHODS: Five hundred and thirty patients with stage I or II cervical carcinoma received surgical treatment between 1966 and 1988. There were 66, 288, 95 and 81 cases of stage IA, IB, IIA and IIB respectively. All patients underwent extensive abdominal hysterectomy and bilateral pelvic lymphadenectomy. The metastatic lesions of periaortic nodes in 18 cases were resected. Three methods of isolating ureter were used. The lymphangiography and dyeing of lymphaden was performed on 94 patients. RESULTS: The five-year survival rate was shown to be correlated with the pathologic type, cytologic grade, clinical stage and nodal metastasis of cervical carcinoma. The five-year survivals in stage IA, IB, IIA and IIB were 95.5%, 93.4%, 90.5% and 77.8% respectively; in squamous carcinoma and adenocarcinoma, 91.5% and 78.1% respectively; in the group with nodal spreading and the group without nodal spreading, 70.2% and 94.6% respectively; in patients of stage IIB treated by the method of isolating ureter outside ureter, 83.1%; and in the group of lymphangiography and dyeing and the group not treated by lymphangiography and dyeing, 84.6% and 63.8% respectively. CONCLUSIONS: The method of isolating ureter outside ureter has an applying value for stage IIB cervical carcinoma. Lymphangiography and dyeing of lymphaden plays a role in raising the rate of nodal dissection.

Adenocarcinoma↗
PubMed1997

[The treatment of lymph nodes metastases of stage I and II cervical carcinoma].

OBJECTIVE: To investigate the treatment methods of nodal metastases of stages I and II cervical carcinoma. METHODS: Surgical data of 84 patients with stages I and II cervical carcinoma were analyzed. All patients underwent extensive abdominal hysterectomy and bilateral pelvic lymphadenectomy, 18 of whom received systematic resection of periaortic metastatic lesions. The method of isolation of the ureters from lateral exterior were performed on 45 patients. Wertheim-Meigs' operation was performed in 39 patients and preoperative lymphangiography and dyeing in 40 patients, followed by radiotherapy and chemotherapy. RESULTS: 77 cases were followed up for more than five years, 55 (71.4%) were alive. In the patients with one node involved, the survival rate was 85.7%, and in those with two or more nodes involved it was 63.3%. The survival rate of the lymphangiography group was 80.0%, and that of the control group 62.2%. The recurrent rate of cardinal ligament nodes was 2.2% in the patients with lateral isolation of the ureters and was 17.9% in the Wertheim-Meigs' group. The survival rate of patients with periaortic metastasis was 52.9%. CONCLUSIONS: Lateral isolation of the ureters and resection of cardinal ligaments with their lymph nodes preoperative lymphangiography and dyeing, and resection of periaortic metastatic nodes could reduce nodal recurrence and raise the five year survival rate.

Adult↗
PubMed1997

[Relationship between human parvovirus B19 infection and spontaneous abortion].

OBJECTIVE: To determine whether there is a relationship between parvovirus B19 infection and spontaneous abortion. METHODS: 105 embryo tissues from spontaneous abortions of unknown cause during 1994-1995 were studied using nested polymerase chain reaction (PCR) assay for parvovirus B19 DNA. As controls 40 fetal tissues were also examined. Among which, 20 were collected from induced abortions, and the others were stillbirths. The positive specimens underwent further study for TORCH infections. RESULTS: 26 (24.5%) were B19 DNA positive in the case group and 2 (5.0%) in the control group. The difference was significant (P < 0.05). Among 26 positive specimens, 5 had cytomegalovirus (CMV) infection as well as 2 had both CMV and herpes simplex virus (RSV) infections. CONCLUSIONS: Parvovirus B19 infection may be an important pathogen for spontaneous abortion, and it is suggested to investigate parvovirus B19 infection among pregnant women in China.

Abortion, Spontaneous↗
PubMed1997

[Quantitative analysis of mRNA level by PCR method using single basemutated template as inner standard].

Using simple polymerase chain reaction (PCR) method, a single base changed mutant was generated, to which an EcoR I restriction site was added at a specific position of the primer template. The copies of the mutant could be quantified after amplification by PCR. Then the diluted mutant used as an inner standard was added into the samples to be detected. In the same PCR reaction, the mutated and primer template DNA were amplified. After digestion by EcoR I, the PCR products were electrophoresed in 2% agarose gel. The DNAs of different size were separated by electrophoresis and the copies of the primer template in the samples was quantified. The experimental results showed that the cDNA copies of AVP V1 receptor in reverse transcription products from 1 microgram of total RNA isolated from liver tissue of Sprague Dawley rats was about 1.25 x 10(-20) mol.

Animals↗
PubMed1997

[Inhibitory effects of L-ENK on the proliferation of cultured smooth muscle cells of rats].

Using method of MTT and 3H-TdR incorporation, the effect of L-ENK on proliferation and DNA synthesis of the cultured thoracic aortic vascular smooth muscle cells (VSMCs) of SD rats was investigated. The results indicated that L-ENK (10(-5)-10(-4) mol/L) could markedly inhibit proliferation and DNA synthesis of VSMCs, while NAL (10(-8)-10(-5) mol/L) had no such effect, but could antagonize the inhibitory action of L-ENK on the proliferation of VSMCs.

Animals↗
PubMed1997

[Effect of stressful stimulations on hypothalamic vasopressin mRNA level of rats].

Experiments were carried out in stressful foot shock and noise stimulated male Sprague Dawlay rats. 3'-end digoxigenin-labeled 26 mer oligonucliotide probe was used to detect the vasopressin (AVP) mRNA in hypothalamic tissues. Dot blotting technique was used in the assessment of AVP mRNA level. The results showed that the tail systolic arterial pressure of rats increased gradually after stressful stimulations of foot shock in combination with noise. The difference in tail systolic blood pressure between control and stimulated rats was statistically significant after 5-day stimulation. By the ninth day, the systolic blood pressure of the stressed rats reached the highest level and maintained thereafter for several days. No significant difference was observed in the AVP-mRNA level between control and stressed rats by the time when stimulated for 4 days, but it significantly increases when stimulated for 6 days or longer (by the 6th day: P < 0.005; by the 15th day: P < 0.001). No difference was found in plasma osmolalities between control and stressed animals. These results indicate that the stressful foot shocks in combination with noise stimulations may cause an increase in AVP-mRNA level in the hypothalamus, which was accompanied by an increase in systolic arterial pressure. The mechanism of increase in AVP-mRNA level upon stress stimulation remains to be elucidated.

Animals↗
PubMed1997

Nitric oxide is involved in the formation of learning and memory in rats: studies using passive avoidance response and Morris water maze task.

The study was designed to test whether blockade of endogenous NO production affects learning and memory formation in rats. The rats received an intracerebroventricular (i.c.v.) injection of the inhibitor of nitric oxide synthase, N omega-nitro-L-arginine (NAME), 30 min before each training, and were then tested in the one-trial passive avoidance response and Morris water maze task, respectively. The results showed that: (1) among four concentrations of drug used, only doses higher than 3 mumol of i.c.v. NAME impaired learning and memory formation significantly (p < 0.05) in both test models; (2) in Morris water maze task, the animals treated with highest dose of NAME (5 mumol) failed to learn while those treated with lower doses succeeded; (3) in Morris water maze task, the i.c.v. NAME, even in higher doses, did not affect the capacity of finding a visible platform. It is suggested that NO is involved in learning and memory formation by potentiating or facilitating mainly the acquisition process.

Animals↗
PubMed1996

Induction of neonatal tolerance by plasmid DNA vaccination of mice.

Plasmid DNA vaccines capable of preventing viral, bacterial, and parasitic infections are currently under development. Our labs have shown that a plasmid DNA vaccine encoding the circumsporozoite protein of the malaria parasite elicits protective immunity against live sporozoite challenge in adult BALB/c mice. We now find that the same DNA vaccine induces tolerance rather than immunity when administered to 2-5 d-old mice. Neonatally tolerized animals were unable to mount antibody, cytokine or cytotoxic responses when rechallenged with DNA vaccine in vitro or in vivo. Tolerance was specific for immunogenic epitopes expressed by the vaccine-encoded, endogenously produced antigen. Mice challenged with exogenous circumsporozoite protein produced antibodies against a different set of epitopes, and were not tolerized. These findings demonstrate important differences in the nature and specificity of the immune response elicited by DNA vaccines versus conventional protein immunogens.

Age Factors↗
PubMed1996

The profile of soluble amyloid beta protein in cultured cell media. Detection and quantification of amyloid beta protein and variants by immunoprecipitation-mass spectrometry.

To study the metabolism of amyloid beta protein (Abeta) in Alzheimer's disease, we have developed a new approach for analyzing the profile of soluble Abeta and its variants. In the present method, Abeta and its variants are immuno-isolated with Abeta-specific monoclonal antibodies. The identities of the Abeta variants are determined by measuring their molecular masses using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The levels of Abeta variants are determined by their relative peak intensities in mass spectrometric measurements by comparison with internal standards of known identities and concentrations. We used this method to examine the Abeta species in conditioned media of mouse neuroblastoma cells transfected with cDNAs encoding wild type or mutant human amyloid precursor protein. In addition to human Abeta-(1-40) and Abeta-(1-42), more than 40 different human Abeta variants were identified. Endogenous murine Abeta and its variants were also identified by this approach. The present approach is a new and sensitive method to characterize the profile of soluble Abeta in conditioned media and biological fluids. Furthermore, it allows direct measurement of each individual peptide in a peptide mixture and provides comprehensive information on the identity and concentration of Abeta and Abeta variants.

Amino Acid Sequence↗
PubMed1996

A dinucleotide deletion in exon 4 of the PlA2 allelic form of glycoprotein IIIa: implications for the correlation of serologic versus genotypic analysis of human platelet alloantigens.

Platelets from a patient with a suspected case of posttransfusion purpura were subjected to alloantigen phenotyping and found to express the PlA1, but not the PlA2, allelic form of human platelet membrane glycoprotein (GP) IIIa on the platelet surface. However, genotyping showed unambiguously that the patient carried the genes for both of these GPIIa alleles. Based on these results, we postulated that the PlA2 allele was silent, ie, that this patient was a carrier for Glanzmann thrombasthenia (GT). Quantitative analysis of GPIIb-IIIa surface expression showed only 20,000 GPIIb-IIIa receptors/platelet, approximately half of the value obtained with control platelets. Southern blot analysis showed no large deletions or insertions within the GPIIIa gene, and amplification of all 14 exons encoding GPIIIa resulted in the production of normal sized polymerase chain reaction (PCR) products in all cases. DNA-sequence analysis showed an AG dinucleotide deletion affecting codons 210 and 211 within exon 4 of the GPIIIa gene, leading to a change in reading frame and the creation of a stop codon 38 nucleotides down-stream. The predicted truncated protein consists of only the first 223 of the normal 762 amino acids, thus accounting for the failure to express the PlA2 allele on the platelet surface. While encountered only rarely, carriers of either GT or Bernard Soulier syndrome that are at the same time heterozygous for human platelet alloantigenic epitopes found on GPIb, GPIIb, or GPIIIa have the possibility to give discrepant results when comparing genotypic versus phenotypic analysis. In such situations, the combination of serologic and DNA-based evaluation contributes complementary and beneficial diagnostic information than either one alone are able to provide.

Alleles↗
PubMed1996

Protection against malaria by Plasmodium yoelii sporozoite surface protein 2 linear peptide induction of CD4+ T cell- and IFN-gamma-dependent elimination of infected hepatocytes.

Plasmodium falciparum sporozoite surface protein 2 (SSP2), also known as TRAP, is included in experimental human malaria vaccines because Plasmodium yoelii SSP2 is the target of protective CD8+ CTL that eliminate P. yoelii-infected hepatocytes in mice. We now report that immunization with a synthetic branched-chain peptide including four copies of a PySSP2 sequence, NPNEPS, and two tetanus toxin T helper epitopes in the adjuvant TiterMax, or with an 18 amino acid peptide (NPNEPS)3 in the adjuvant protects A/J, but not BALB/c or C57BL/6 mice. Transfer of T lymphocyte-enriched immune splenocytes protects naive mice; in vivo depletion of CD4+ T cells eliminates vaccine-induced protection; and in vivo treatment with anti-IFN-gamma reverses vaccine-induced activity against infected hepatocytes. Lymph node cells from immunized A/J, BALB/c, and C57BL/6 mice recognize the (NPNEPS)3 peptide in vitro. However, the protected A/J mice respond with a predominantly Th1 pattern of lymphocyte response, and the non-protected strains of mice respond with a Th2 pattern. There are many examples of CD4+ T cells transferring protection against infectious organisms. However, to our knowledge, this is the first formal demonstration that immunization with a linear synthetic peptide induces CD4+ T cell-dependent, IFN-gamma dependent, genetically restricted sterile protective immunity against an infectious agent.

Adoptive Transfer↗
PubMed1996

CD95-dependent bystander lysis caused by CD4+ T helper 1 effectors.

CD95-dependent lysis of target cells by CD4+ cells raises important questions of specificity and its potential role in inflammation. Much of what we know about CD95L-dependent killing is in fact bystander killing because the T cells have been previously activated by pharmacologic reagents. In an effort to better understand its significance in a more physiologic setting, we have examined bystander lysis by Th1 cells stimulated by Ag and APC in a murine model system. We find that bystander lysis is readily stimulated by M phi APC but not some epithelial lines, even though they themselves are killed in a CD95-dependent process while serving as APC. Bystander activity requires close proximity between the T cell, the APC, and the bystander target because bystanders are not lysed during coculture in Transwells.

Animals↗
PubMed1996

Stoichiometry of a recombinant GABAA receptor.

GABA is the main inhibitory neurotransmitter in the mammalian brain. The postsynaptic GABAA receptor/pore complex is presumed to be a pentamer typically composed of a combination of alpha, beta, and gamma subunits, although the stoichiometry remains controversial. We probed the stoichiometry of the GABAA receptor by site-directed mutagenesis of a conserved leucine (to serine) in the putative second membrane-spanning domain of the rat alpha 1(alpha L263S), beta 2(alpha L259S), and gamma 2(alpha L274S) subunit isoforms. Coexpression of wild-type and mutant subunits of each class (e.g., alpha and alpha L263S), along with their wild-type counter-parts (e.g., beta and gamma), in Xenopus laevis oocytes resulted in mixed populations of receptors with distinct GABA sensitivities. This is consistent with the interpretation that the leucine mutation increased the GABA sensitivity in proportion to the number of incorporated mutant subunits. The apparent number of incorporated subunits for each class (alpha, beta, and gamma) could then be determined from the number of components comprising the compound GABA dose-response relationships. Using this approach, we conclude that the recombinant alpha 1 beta 2 gamma 2 GABAA receptor is a pentamer composed of two alpha subunits, two beta subunits, and one gamma subunit.

Amino Acid Sequence↗
PubMed1996

Genetic identification of a gene involved in constitutive, high-affinity nitrate transport in higher plants.

Two mutations have been found in a gene (NRT2) of Arabidopsis thaliana that specifically impair constitutive, high-affinity nitrate uptake. These mutants were selected for resistance to 0.1 mM chlorate in the absence of nitrate. Progency from one of the backcrossed mutants showed no constitutive uptake of nitrate below 0.5 mM at pH 7.0 in liquid culture (that is, within 30 min of initial exposure to nitrate). All other uptake activities measured (high-affinity phosphate and sulfate uptake, inducible high-affinity nitrate uptake, and constitutive low-affinity nitrate uptake) were present or nearly normal in the backcrossed mutant. Electrophysiological analysis of individual root cells showed that the nrt2 mutant showed little response to 0.25 mM of nitrate, whereas NRT2 wild-type cells showed an initial depolarization followed by recovery. At 10 mM of nitrate both the mutant and wild-type cells displayed similar, strong electrical responses. These results indicate that NRT2 is a critical and perhaps necessary gene for constitutive, high-affinity nitrate uptake in Arabidopsis, but not for inducible, high-affinity nor constitutive, low-affinity nitrate uptake. Thus, these systems are genetically distinct.

Arabidopsis↗
PubMed1996

Cellular adherence elicits ligand-independent activation of the Met cell-surface receptor.

Cell adhesion has a fundamental role in the proliferation and motility of normal cells and the metastasis of tumor cells. To identify signaling pathways activated by the adherence of tumor cells, we analyzed the tyrosine phosphorylation of proteins in mouse melanoma cells before and after attachment to substrata. We discovered that cellular adherence activated the protein-tyrosine kinase of the cell surface receptor Met, whose ligand is hepatocyte growth factor and scatter factor. The activation was exceedingly prompt, affected the great majority of Met in the cells, persisted so long as the cells remained adherent, and was rapidly reversed as soon as the cells were detached from substrata. Activation of Met required that cells be adherent but not that they spread on the substratum, and it occurred in the absence of any apparent ligand for the receptor. Ligand-independent activation of Met occurred in several varieties of tumor cells but not in normal endothelial cells that express the receptor. The activation of Met described here may represent a means by which cells respond to mechanical as opposed to biochemical stimuli.

Animals↗