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Biomedical subjects

L Guo

Publications and source records attributed to L Guo.

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

[Function of B7/CD28 in anti-myeloma immunoreaction through activating T cells].

OBJECTIVE: To explore the role of B7/CD28 molecule in priming the anti-myeloma effect of T lymphocyte and the mechanism by which CD28 promoted the immunogenicity of myeloma cells. METHODS: Human B7-1 gene was transducted into XG-s cells. CD28 agonist monoclonal antibody was primed. Primary allogeneic MLR, immunophenotypic analysis and quantitative measurement of IL-2 were performed. RESULTS: XG cells were successfully transfected with B7-1 cDNA. The expressions of CD54, CD58, CD11a/CD18, CD40, CD40L, CD56, B7-2(CD86), HLA-I and HLA-II molecules were not affected by the transfection. The transduction of B7 gene dramatically increased the immunogenicity of tumor cells. In allo-MLR, the B7-1 expressing XG cell could more effectively mediate the activation, proliferation and IL-2 secretion of alloantigenic CD8+ T cells than XG cells did. Like B7-1 molecules, anti-CD28 agonistic McAb could induce the MLR of allo-T cell. CONCLUSION: Human multiple myeloma cells failed to induce antitumor immunoreaction because of the weak expression of B7 molecules. The transfection of B7-1 or CD28 agonist antibody could stimulate and proliferate T lymphocytes and increase the immunogenicity of myeloma cells. CD28 agonist antibody might be promising for clinical application.

Antibodies, Monoclonal↗
PubMed1999

[Clinical study of fibrinolysis indicators in patients with chronic pulmonary heart disease].

OBJECTIVE: To investigate the change of D-dimer and other fibrinolysis indicators in patients with chronic pulmonary heart disease. METHODS: The fibrinolytic activity of plasma was measured in 42 patients with chronic pulmonary heart disease and in 20 controls (matched with sex and age). RESULTS: The D-dimer level was significantly higher in exacerbated patients than in controls (P < 0.001). The fibrinolytic activity in patients was lower than in controls. The plasma fibrinolytic activity was positively correlated with PaO2 and negativly correlated with PaCO2. CONCLUSIONS: The depressed fibrinolysis may be associated with hypercoagulability state of chronic pulmonary heart disease and contributes to thrombi in small pulmonary arteries and arterioles. D-dimer can be used in diagnosis of thrombi formation in small pulmonary arteries and arterioles. Patients with chronic pulmonary heart disease can be treated with fibrinolysis drugs.

Aged↗
PubMed1999

[Characteristics of expression of CD44v and receptor for HA-mediated motility (RHAMM) in multi-step gastrocarcinogenesis].

OBJECTIVE: To explore the potential significance of expression of CD44 and RHAMM at different stages of gastric carcinogenesis. METHODS: The expression pattern of CD44 and RHAMM in non-cancerous mucosa, preneoplastic lesions and carcinomas of the stomach was examined by RT-PCR, Southern blot hybridization, immunohistochemical staining and Western blot hybridization. RESULTS: Expression of CD44 v5 could be observed not only in cancers, but also in pre-neoplastic and non-cancerous specimens. CD44 v7 was commonly seen in non-cancerous lesions but its expression tended to decrease with the progression of pre-malignant phenotype. CD44 v8-v10 could only be observed in some intestinal metaplasia, dysplastic proliferation and undifferentiated carcinoma. Nevertheless, CD44 v6 was found exclusively in cancer tissues, with a positive rate of 14%. The frequency of RHAMM detection was about 10% in non-cancerous mucosa but tended to increase with tumor development, reaching an average of 74% in gastric cancers. In 80% of the invading cancer cells, RHAMM and CD44v coexpressed, or complementarily expressed. CONCLUSION: Expression of RHAMM is more associated with progression of gastric malignancy. Irrespective of its low frequency, CD44 v6 is still a reliable marker of malignant transformation of gastric mucosa. Co-expression or complementary expression of CD44v and RHAMM might facilitate invasion and metastasis of gastric cancer.

Extracellular Matrix Proteins↗
PubMed1999

[Prediction of the outcome of dysplasia of esophageal epithelium by high resolution image analysis].

OBJECTIVE: To predict the outcome of dysplasia of esophageal epithelium by means of high resolution image analysis(HRIA). METHODS: Asymptomatic adults were examined for balloon cytology of the esophagus in 1983 from Heshun Commune of Linxian County. Ninety three cases of severe dysplasia and 122 cases of mild dysplasia of the esophagus were selected for this study. By means of an Axiomat-microscope equipped with TV-camera, 100 normal nuclei of well-preserved cells in the intermediate layer of Pap-stained squamous epithelium were randomly examined. RESULTS: Of the 93 cytologically diagnosed severe dysplasia cases, 24, 14 and 7 progressed to carcinoma in 3, 5 and 9 years, respectively. In the other 48 cases, dysplasia remained stable or regressed to normal. The other cases were used as the control. According to chromatin features, correct diagnosis of cases was achieved by HRIA in 75.0%(18/24), 85.7%(12/14) and 85.7%(6/7) of the cases examined, respectively (P < 0.001). Of the 122 cytologically diagnosed mild dysplasia, 16, 13 and 12 cases progressed to carcinoma in 3, 5 and 9 years, respectively. The other 81 cases remained stable or regressed to normal. Correct diagnosis was made by HRIA in 93.8%(15/16), 76.9%(10/13) and 83.3%(10/12) of the cases examined, respectively (P < 0.001). CONCLUSION: Chromatin nuclear features examined by HRIA can predict the outcome of precancerous lesions and discriminate progressor from non-progressor ones. It can be used as surrogate endpoint biomarkers for the evaluation of efficacy of chemoprevention trial.

Adult↗
PubMed1999

[The significance of p16, cyclin D1 and pRb expression in soft tissue leiomyosarcoma].

OBJECTIVE: To evaluate the significance of p16, cyclin D1 and pRb expression in human soft tissue leiomyosarcoma (LMS) and the relationship among these three proteins. METHODS: 42 cases of LMS were studied for p16, cyclin D1 and pRb expression with immunohistochemical method. RESULTS: The total abnormality percentage of p16, cyclin D1 and pRb expression in all 42 cases of LMS was 97.6%. The negative rate of p16 and pRb protein expression was 35.7% and 47.6% respectively, and the overexpression rate of cyclin D1 was 57.1%. Overexpression of cyclin D1 was also noticed in 55% leiomyomas. In the 20 cases of LMS which were pRb negative, 19 cases were moderately or strongly positive and one faintly positive for p16. Contrastly, in the 15 cases of LMS negative to p16, 12 cases were moderately or strongly positive and 3 cases faintly positive for pRb. Higher rates of loss of pRb protein were observed in the low-differentiated group than in the high-differentiated one. CONCLUSIONS: (1) The abnormality of p16-cyclin-pRb pathway is highly related to the pathogenesis of LMS. (2) Loss of p16 or pRb and/or overexpression of cyclin D1 may be involved in the pathogenesis of LMS. (3) There is a negative reciprocity between p16 and pRb protein expression in LMS. (4) Overexpression of cyclin D1 is a common molecular alteration that may occur in the early stage. (5) Expression of pRb is inversely related to the differentiation degree of LMS. (6) The expression of the 3 proteins studied has no relation to tumor location, recurrence, invasion or metastasis.

Biomarkers, Tumor↗
PubMed1999

[Construction of Streptococcus mutans surface protein antigen eukaryotic expression vector pcDNA3-PAc. II. Testified efficiency of repeated using glass fiber chromatographic column].

OBJECTIVE: To explore one method getting highly purified plasmid DNA and costing low. METHODS: According to principle of extraction and purification plasmid DNA of glass fiber chromatographic column, its operation sequence was improved so that disposable glass fiber chromatographic column could be used repeatedly. The concentration and purity of plasmid DNA obtained by 12 times repeated using glass fiber chromatographic column were determined by spectrophotometry. Moreover, Those plasmid DNA obtained were tested by restriction enzyme and agarose gel electrophoresis, Ligation in vitro and transformation test. RESULTS: 12 times repeated use of glass fiber chromatographic column made no significant difference to the concentration and purity of obtained plasmid DNA (P < 0.05), and plasmid DNA was completely digested by restriction enzyme. The digested fragments were well ligated together by the action of T4 DNA Ligase in ATP ligating buffer in vitro and ligated DNA was well transformed into E. coli. CONCLUSION: Repeated use glass fiber chromatographic column can obtain a lot of highly purified plasmid DNA and cost is low. Digestion, ligation and transformation of those plasmid DNA are not affected. The results may be significant in molecular cloning and study of gene vaccination.

Antigens, Surface↗
PubMed1999

[Preparation, purification and identification of sialic acid from Escherichia coli C-8].

Colominic acid produced from Escherichia coli C-8 was purified by ammonia sulfate precipitation, dialysis and concentration. After hydrolysis of colominic acid at a pH of 2.5, at 70 degrees C for 4 h, sialic acid was obtained, then purified by chromatography on Dowex1-x8. Analysis of thin-layer chromatography and absorption spectrum of sialic acid in the orcinol/Fe3+/HCl and the periodic acid/thiobarbituric acid confirmed that its purity was identical with that of standard sample.

Chromatography, Thin Layer↗
PubMed1999

[Isolated sphenoid sinus disease].

OBJECTIVE: The purpose of this study is to review isolated sphenoid sinus disease, to establish correct diagnosis and to treat it effectively in the future. METHOD: 26 patients underwent endoscopic surgery, in which 20 sphenoid sinus mucocoeles were removed and 6 sphenoid sinuses were explored. 3 sphenoid sinus mucocoeles were removed by external approach, 1 patient underwent skull base surgery and decompression of optic nerve. RESULT: 24 patients were free from disease postoperatively within 0.5-4 years follow-up, 2 patients underwent re-operation because of recurrence, 1 patient was undergoing radiotherapy, 3 patients could not contact. CONCLUSION: This study shows that CT not only makes contribution to establish correct diagnosis but also plays an important role in surgery of isolated sphenoid sinus disease. Endoscopic surgery is valuable in treatment for benign disease of sphenoid sinus.

Adolescent↗
PubMed1999

[Orthogonal experiments on extract-concentrate-spray drier related technological factors for shuguanwenjing granule].

By using orthogonal tests, with the ratio of dry powder abtained from crude drugs and the Icariin content of powder as criteria, the correlation among the extract-concentrate-spray drier technology for Shuguanwenjing Granule and the main technological factors such as time and frequency of decoction, volume of water, relative density of extract, the in-temperature and out-temperature of spray drier, etc. was studied.

Drug Combinations↗
PubMed1999

Differential gene expression in retina of myopic chicken eyes using mRNA differential display.

PURPOSE: To study differentially expressed genes in retina of experimental myopic chicken. METHODS: Experimental myopia in chicken was induced by form-deprivation. The mRNA in chicken retina was analyzed by using differential display. RESULTS: Experimental myopia was successfully induced in chicken through form-deprivation. Differentially expressed gene fragments were detected in retina of chicken with myopic development and recovery as compared with normal controls. CONCLUSION: The differential display of mRNA may be a useful way in cloning myopic-related genes.

Animals↗
PubMed1999

[A preliminary clinical safety evaluation of parvovirus H-1 on cancer therapy].

OBJECTIVE: To make a preliminary evaluation of parvovirus H-1 for its safety in clinical use. METHODS: In this study, clinical safety of H-1 in cancer therapy was examined using the Ames test, the mammalian cell chromosome aberration test, the micronucleus calculation of mouse bone marrow cells, the allergy test and the pyrogenicity test. RESULTS: Negative results were observed in all the tests. The mouse tolerance test showed that the tolerance limit was at least 5 x 10(11) plaque-forming units/kg weight, which was 2500 times higher than the supposed clinical dose. The H-1 host NB-324K cells were also tested using the anchorage-independent assay and the tumour formation in nude mice. Both of the assays gave negative results. CONCLUSION: All these results preliminarily showed that the H-1 was safe in cancer therapy.

Animals↗
PubMed1998

Site-directed mutational analysis for the membrane binding of DnaA protein. Identification of amino acids involved in the functional interaction between DnaA protein and acidic phospholipids.

DnaA protein, the initiator of chromosomal DNA replication in Escherichia coli, interacts with acidic phospholipids, such as cardiolipin, and its activity seems to be regulated by membrane binding in cells. In this study we introduced site-directed mutations at the positions of hydrophobic or basic amino acids which are conserved among various bacteria species and which are located in the putative membrane-binding region of DnaA protein (from Asp357 to Val374). All mutant DnaA proteins showed much the same ATP and ADP binding activity as that of the wild-type protein. The release of ATP bound to the mutant DnaA protein, in which three hydrophobic amino acids were mutated to hydrophilic ones, was stimulated by cardiolipin, as in the case of the wild-type protein. On the other hand, the release of ATP bound to another mutant DnaA protein, in which three basic amino acids were mutated to acidic ones, was not stimulated by cardiolipin. These results suggest not only that the region is a membrane-binding domain of DnaA protein but also that these basic amino acids are important for the binding and the ionic interaction between the basic amino acids and acidic residues of cardiolipin and is involved in the interaction between DnaA protein and cardiolipin.

Adenosine Diphosphate↗
PubMed1998

Lipid A acylation and bacterial resistance against vertebrate antimicrobial peptides.

The Salmonellae PhoP-PhoQ virulence regulators induce resistance to host cationic antimicrobial peptides (CAMP) after infection of vertebrate tissues, and Mg2+ or Ca2+ limitation. The PhoP-PhoQ activated gene, pagP, was identified as important to inducible CAMP resistance and increased acylation of lipid A, the major component of the outer leaflet of the outer membrane. pagP mutants demonstrated increased outer membrane permeability in response to CAMP, supporting the hypothesis that increased lipid A acylation is a CAMP resistance mechanism. Similarly, in response to Mg2+ limited growth, other enteric Gram-negative bacteria demonstrated increased lipid A acylation. Compounds that inhibit the ability to increase lipid A acylation may have utility as new antimicrobial agents.

Acylation↗
PubMed1998

Synthesis and biological activities of potent peptidomimetics selective for somatostatin receptor subtype 2.

A series of nonpeptide somatostatin agonists which bind selectively and with high affinity to somatostatin receptor subtype 2 (sst2) have been synthesized. One of these compounds, L-054,522, binds to human sst2 with an apparent dissociation constant of 0.01 nM and at least 3,000-fold selectivity when evaluated against the other somatostatin receptors. L-054,522 is a full agonist based on its inhibition of forskolin-stimulated adenylate cyclase activity in Chinese hamster ovary-K1 cells stably expressing sst2. L-054,522 has a potent inhibitory effect on growth hormone release from rat primary pituitary cells and glucagon release from isolated mouse pancreatic islets. Intravenous infusion of L-054,522 to rats at 50 microgram/kg per hr causes a rapid and sustained reduction in growth hormone to basal levels. The high potency and selectivity of L-054, 522 for sst2 will make it a useful tool to further characterize the physiological functions of this receptor subtype.

Animals↗
PubMed1998

Expression profiles of multiple genes in single neurons of Alzheimer's disease.

Many changes have been described in the brains of Alzheimer's disease (AD) patients, including loss of neurons and formation of senile plaques and neurofibrillary tangles. The molecular mechanisms underlying these pathologies are unclear. Northern blot, dot-blot, and reverse transcription-coupled PCR analyses have demonstrated altered expression levels of multiple messages in AD brain. Because not all cells are equally affected by the disease, these methods obviously cannot study the changes in relation to disease states of individual cells. We address this problem by using antisense RNA profiling of single cells. We present expression profiles of single neurons at early and late stages of AD and describe statistical tools for data analysis. With multivariate canonical analysis, we were able to distinguish the disease state on the basis of altered expression of multiple messages. To validate this approach, we compared results obtained by this approach with results obtained by in situ hybridization analysis. When the neurofilament medium subunit was used as a marker, our results from an antisense RNA profiling revealed no change in neurofilament medium subunit expression between early- and late-stage AD, consistent with findings obtained with in situ hybridization. However, our results obtained by either analysis at the single-cell level differed from the reported decrease in AD neocortex obtained by Northern blot analysis [Kittur, S., Hoh, J., Endo, H., Tourtellotte, W., Weeks, B. S., Markesbery, W. & Adler, W. (1994) J. Geriatr. Psychiatry Neurol. 7, 153-158]. Thus, the strategy of using the single-cell antisense RNA approach to identify altered gene expression in postmortem AD brain, followed by detailed in situ hybridization studies for genes of interest, is valuable in the study of the molecular mechanisms underlying AD neuropathology.

Aged↗