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Biomedical subjects

W Li

Publications and source records attributed to W Li.

At least 307 records · Page 17Linked to original sources
PubMed2001

[The diagnostic value of platelet glycoprotein-specific autoantibody detection in autoimmune thrombocytopenic purpura].

OBJECTIVE: To evaluate the clinical significance of platelet glycoprotein-specific autoantibody detection and platelet-associated IgG (PAIgG) measurement in the differential diagnosis between autoimmune thrombocytopenia and nonimmune thrombocytopenias. METHODS: Anti- GP II b/III a and anti-GP I b/IX autoantibodies were detected by a modified monoclonal antibody immobilization of platelet antigens assay (modified MAIPA), and PAIgG by competitive ELISA. RESULTS: Comparing with the measurement of PAIgG, the GP-specific autoantibody assay was less sensitive but much more specific for the diagnosis of autoimmune thrombocytopenia. CONCLUSION: The platelet GP-specific autoantibody detection is considerably better than PAIgG measurement in discriminating immune from nonimmune thrombocytopenia.

Adolescent↗
PubMed2001

[Study of enzyme immunosensor immobilized by regenerated silk fibroin].

The author studies the enzyme immunosensor made up of graphite electrode and protein film of regenerated silk fibroin which is employed to immobilized antigen (rabbit IgG). IgG will be recognized and combined by antibody (goat-anti-rabbit IgG-HRP). After enlarging the signal of the combination of antigen and antibody by H2O2, the concentration of IgG is able to be measured by testing the electrode potential directly. The Enzyme Immunosensor is sensitive when measuring IgG and the detection limit of 1.2 x 10(-10) mol/L is found. It shows linear response over the concentration range of 4.1 x 10(-7)-1.2 x 10(-10) mol/L. Electrophoresis cuts down the time of antibody-antigen interaction from 90 min to 30 min. The response time is 15 s. Enzyme immunosensor with better stability and higher sensitivity can be used extensively in clinical diagnosis, medical and environmental studies, HLA molecular diagnosis and so on.

Biosensing Techniques↗
PubMed2001

[Studies on quality specification standards for Saposhnicovia divaricata (Turcz.) Schischk].

OBJECTIVE: To work out a qualitative-quantitative standard for Saposhnikovia divaricata. METHOD: TLC and HPLC were adopted. RESULT: Four chromone compounds were identified by TLC, and the contents of two chromone compounds were determined by HPLC. CONCLUSION: Prim-O-glucosylcimifugin, 4'-O-beta-D-glucosyl-5-O-methylvisamminol, sec-O-glucosylhamaudol and cimifugin should be present simultaneously in S. divaricata. The contents of prim-O-glucosylcimifugin and 4'-O-beta-D-glucosyl-5-O-methylvisamminol in S. divaricata should not be lower than 0.12% respectively.

Apiaceae↗
PubMed2001

[Immune response of mice to replication-defective recombinant adenovirus containing glycoprotein gene of rabies virus 3aG strain].

OBJECTIVE: To evaluate the immune response, of mice immunized with E1, E3 deleted replicative deficient recombinant adenovirus which can express glycoprotein of Chinese 3aG rabies virus. METHODS: Rapid fluorescent focus inhibition test (RFFIT) was used to determine the titer of neutralizing antibodies; specific antigen induced spleen lymphocyte proliferation was determined by in vitro 3H-TdR in-corporation assay, and lethal intracerebral challenge with CVS rabies virus was used to evaluate the protective effectiveness of the recombinant virus as candidate vaccine. RESULTS: Mice immunized by 1 x 10(7) recombinant virus developed high levels of rabies virus neutralizing antibodies (VNA). The spleen lymphocyte of the immunized mice also demonstrated remarkable increased proliferation after stimulation with inactivated rabies virus; 70%-90% of the mice immunized by the recombinant virus were protected from lethal intracerebral challenge with CVS rabies virus. CONCLUSION: E1, E3 deleted replication defective recombinant adenovirus containing 3aG glycoprotein gene may be developed as effective rabies vaccine to control rabies in China.

Animals↗
PubMed2001

[Studies on insulin-like growth factor I receptor in fetal rats with intrauterine growth retardation].

OBJECTIVE: This study was conducted to detect the localization of the insulin-like growth factor I receptor (IGF-I R) in the cells and tissues in the rats with intrauterine growth retardation (IUGR) and normal growth rats. METHODS: 21 pregnant rats were randomly divided into the experimental group (IUGR) (n = 12) and the control group (n = 9). Animal models for IUGR were established by clamping the uterine vasculature of pregnant rats for 20 minutes on day 14 of gestation. The control group rats were subjected to Sham-operation. On day 22 of gestation, fetal rats were delivered by cesarean section. Immunohistochemical assay was performed to detect the IGF-I R expression on liver and lung using specific polyclonal antibodies to rat IGF-I R. RESULTS: In the experimental group, the IUGR rats' body weight, height, and the weight of their liver, lung and the placenta were significantly lower than those in the control group. In the IUGR rats' liver, the area ratio of IGF-I R was increased and the average gray level was decreased, compared with those in the control group. In the IUGR rats' lung, the area ratio of IGF-I R was increased, compared with that in the control group, but no difference of average gray level was observed between the two groups. CONCLUSION: The increased expression of IGF-I R in rats with IUGR, may be due to the decrease of IGF-I and the compensative mechanism of the body.

Animals↗
PubMed2001

[Investigation of the tongue squamous cell carcinoma prognostic factors].

OBJECTIVE: The aim of this study was to investigate the factors which influence the prognosis of the tongue squamous cell carcinoma (TSCC). METHODS: The Cox's proportional hazard model was used to analyze 121 cases of TSCC treated by the affiliated dental hospital of West China University of Medical Sciences in the period from 1990 to 1994. Thirteen parameters (age, sex, occupation, primary tumor site, clinical stage, tumor differentiation, clinical therapy, cervical lymph node metastasis, surgical margin status of the primary tumor, amount of blood transfusion, smoking, drinking, reconstruction during operation) were evaluated. RESULTS: The monofactor analysis showed that factors influencing the postoperative survival of TSCC included primary tumor site, the surgical margin status of the primary tumor and the cervical lymph node metastasis (P < 0.05). Multifactor analysis demonstrated that two of these thirteen relevant factors influenced the postoperative survival of TSCC independently. They are successively the surgical margin status of the primary tumor and the cervical lymph node metastasis (P < 0.05). CONCLUSION: This study suggests that it is critical for surgeons to resect the primary tumor and the metastatic cervical lymph nodes thoroughly to improve the survival rate of TSCC patients.

Adult↗
PubMed2001

[Diagnosis and surgical treatment of carotid body tumor].

OBJECTIVE: To promote the rate of diagnosis and successful rate of operation for carotid body tumor. METHOD: 26 cases of the 30 patients with carotid body tumor were performed by DSA and 5 cases of them, feeding arteries of tumor were embolized with gelfoam through superlective catheterization, preoperativelly. The tumor was resected under carotid adventitial plane in 12 cases, with extracervical artery in 8 cases and with tumor-carotid segment block in 10 cases. RESULT: Of the 30 cases, no one died from operation or cerebral vascular complications. DSA plays a significant role in diagnosis of the tumor. Intraoperative bleeding can be remarkably reduced if feeding arteries were embolized preoperativelly. The tumor fixed to segment of the carotid arteries block was resected and the reconstruction of vasculature was unnecessary as soon as candidates were certified to be qualified by carotid training and DSA or/and TCD tests. Follow up of these 30 patients revealed that 25 of them survived free from cerebrovascular complications and tumor recurrence for 5 months-10 years. 1 of them died from traffic accident 2 year after operation, 4 of them had lost communication. CONCLUSION: DSA is a most authritative approach for diagnosis of carotid body tumor, DSA and TCD tests play a key role to resect carotid artery without reconstruction. Successful operation based on a precise preoperative evaluation, choice of operative ways and proper procedure.

Adult↗
PubMed2001

[Study on the application of quantitative analysis of cell-wall amino acids in actinomycetes classification].

This paper has collected 70 recognized type strains of actinomycete from home and abroad Microbiological culture collection centers. Adopting thin-layer chromatography and thin-layer chromatogram scanner methods to quantitatively analyze the composition of cell-wall amino acids in actinomycete. It has made comparison between quantitative results and qualitative ones. After a thorough discussion, a revision is made on the standard of dividing cell-wall types in actinomycete chemical classification, which has provided some original suggestion in hope of improving the research of actinomycete chemical classification.

Actinobacteria↗
PubMed2001

[Production and some properties of a beta-glucanase from Trichoderma sp. GXC].

The factors affecting Trichoderma sp. GXC for beta-glucanase (1,3-1,4-beta-D-glucan 4-glucanohydrolase, EC 3.2.1.73) production have been investigated, the optimal conditions were that carbon and nitrogen sources were bran and ammonium sulfate, respectively, initial pH 4.0-5.0, shaken at 30 degrees C for 44 h. beta-glucanase was purified to electrophoretic homogeneity by using ammonium sulfate precipitation, Sephadex G-100 and DEAE-Sephadex A-50 chromatography. It's molecular weight was 35 kD by SDS-PAGE, and the enzyme functioned optimally at pH6.0 and 50 degrees C, respectively. In addition, the enzyme was stable at pH 4.0-5.0 and below 40 degrees C. The beta-glucanase activity was significantly inhibited by Fe3+ and stimulated by Co2+, respectively.

Enzyme Stability↗
PubMed2001

[The relationships of the serum concentrations of insulin-like growth factors in fetal rats with intrauterine growth retardation].

OBJECTIVE: To observe the alterations of serum insulin-like growth factor-I,-II (IGF-I, IGF-II) in rat fetus and to investigate the relationship of serum IGFs with intrauterine growth retardation (IUGR). METHODS: 21 pregnant SD rats were randomly divided into control group (n = 9) and experimental group (IUGR group, n = 12). On day 14 of gestation, the bilateral uterine arteries and veins of experimental group were clamped for 20 minutes to build the rat IUGR models and sham surgeries were performed on control group. Fetal serum concentrations of IGFs, birth weight, the length and weight of fetal liver, lung, brain and placenta of all rats in the two groups were measured and compared. RESULTS: The serum concentrations of IGF-I,-II of IUGR group were 117.92 +/- 26.58 ng/ml and 223.19 +/- 33.35 ng/ml, respectively, which were significantly lower than those of control group (234.43 +/- 70.65 ng/ml and 397.74 +/- 23.69 ng/ml, respectively, P < 0.01). Likewise, birth weight, the length and weight of liver, lung, brain and placenta in IUGR group were significantly lower than those in control group (P < 0.05). CONCLUSION: The decrease of fetal serum concentrations of IGF-I,-II may be one of the internal factors contributing to fetal IUGR, and IGFs may play an important role in fetal growth.

Animals↗
PubMed2001

[The reconstruction of laryngeal function in subtotal laryngectomy by pedicled flaps].

OBJECTIVE: To explore the possibility of subtotal laryngectomy in the treatment of advanced laryngeal cancer and selection of reconstruction. METHODS: Forty patients were treated surgically by subtotal laryngectomy with preservation of arytenoid cartilage and perichondrium. The pedicled flaps between cricoid cartilage and arytenoid cartilage were sewed up. The new larynx was reconstructed by suturing the cricoid or trachea to the hyoid bone or the tongue base. RESULTS: The 3 and 5 year survival rates were 85.0% and 76.2% respectively. Decannulation rate was 92.5%. CONCLUSION: The reconstruction of laryngeal function in subtotal laryngectomy by pedicled flaps not only is safe and beneficial to the patients with the cancers above the cricoid, but also improves the quality of patient's life.

Adult↗
PubMed2001

[Structure determination of the constituents from Citrus grandis Osbeck].

OBJECTIVE: To isolate the chemical constituents of the peelings of Citrus grandis and determine their structure. METHOD: Column chromatography and PTLC were applied to isolating and purifying the chemical constituents, and 1H NMR and 13C NMR were used to elucidate their structure. RESULT: 4 compounds were isolated as meranzin hydrate(1), roseoside(2), 8-(3-beta-D-syl-2-hydrox-3-methylbutyl)-7-methoxycoumarin(3) and glucose(4). CONCLUSION: Compound 2 was isolated as a carotenoid from this genus for the first time.

Citrus↗
PubMed2001

Surgical treatment of malignant esophageal tumors in PUMC Hospital.

To study how to prolong the postoperative survival time of the patients with malignant esophageal tumors. The clinical data of 1098 patients with malignant esophageal tumors from 1961 to 1992 were retrospectively analyzed. The deletion of fragile histamine triplet (FHIT) gene (a tumor suppressor gene) in 30 fresh esophageal samples obtained in 1996 was detected with PCR and RT-PCR method. The resectability was raised gradually and the operative morbidity and mortality decreased year by year, but there was no significant improvement on the postoperative 5-year survival rate. Delayed diagnosis and irradical resection influenced the long-term survival. The deletion of cDNA of FHIT gene was 64. 2% in esophageal cancer and 20% in the resected margin of the cancer. We believe that high-grade atypical hyperplasia in esophageal epithelium and deletion of FHIT gene in esophageal cancer and its resected margin are pathological and molecular markers for early diagnosis of esophageal cancer respectively, and the latter may be one of the molecular markers for the resection. Early diagnosis and treatment, radical, resection, and postoperative nutritional support are very important for the improvement of the postoperative survival time of the patients.

Acid Anhydride Hydrolases↗
PubMed2001

[Molecular orientation of copper phthalocyanine derivative in copper phthalocyanine-Fe2O3 nanoparticles alternating LB films].

Copper phthalocyanine-Fe2O3 nanoparticles alternating thin films were fabricated by Langmuir-Blodgett technique. Molecular orientation of [4-(4'-benzyloxy phenyl sulfonyl)phenoxy]-tris-4-(2,4-di-t-phenoxy) phthalocyanine copper (II) in its alternating LB films, deposited at different conditions, was studied by polarized UV-Vis spectra. The tilt extent of the copper phthalocyanine molecule on its LB films increases with the surface pressure of the subphase increasing on the same subphase, or with Fe2O3 concentration decreasing at the same pressure. The orientation of the copper phthalocyanine derivative is important for the gas-sensing properties. The bigger the tilt extent of the phthalocyanine molecule is, the greater the sensitivity of the film is.

Ferrous Compounds↗
PubMed2001

[Fine structure branching ratio for K-Ar optical collision].

An optically thin gaseous mixture of K and low-density Ar is excited by the fixed frequency line 514.5 nm of the argon ion laser. The excited KAr molecule is dissociated into the K 4P1/2 or K 4P3/2. The branching ratio is defined as I(D1)/I(D2) where I(D1) and I(D2) are measured intensities of the atomic K D1 and D2 lines. The branching is determined in the Ar density range between 2 and 8 x 10(17) cm-3. The ratio of the dissociation rates and the fine structure changing cross section are obtained.

Argon↗
PubMed2001

[Studies on extraction process of Phyllanthus urinaria].

OBJECTIVE: To optimize the extraction process of Phyllanthus urinaria L. METHOD: The optimum extraction condition was investigated by the orthogonal design in flavonoids content as index. RESULTS: The factors influencing extraction efficiency were as follows: D > A > B> C (A: Concentration of ethanol, B: The amount of ethanol added, C: Time of extraction, D: Times of extraction). The optimum extraction condition was: extracting the drug for 3 times, every time for 2 hour, after adding 8 fold of ethanol, utilizing concentration of ethanol for 70%. CONCLUSION: The optimized process is stable and high efficient.

Chemistry, Pharmaceutical↗
PubMed2001

[The cytotoxic effect of a low density lipoprotein delivered aclarubicin on leukemia cells].

OBJECTIVE: To investigate the feasibility and effectiveness of low density lipoprotein (LDL) particles as a carrier of a lipophilic anthracycline drug aclarubicin (ACR) for targeting delivery to an acute monocytic leukemia cell line THP-1. METHODS: LDL-ACR complex was prepared by incubating LDL with ACR. The intracellular ACR content was assayed fluorometrically. Cytotoxicity was studied by cell protein measurement and 3H-TdR incorporation test. RESULTS: Intracellular accumulation of LDL-ACR was reduced when THP-1 cells were incubated in the presence of native LDL, but methylated LDL had no effect on the cellular LDL-ACR accumulation. The LDL-ACR complex caused a greater inhibition of the growth of THP-1 cells than that of normal bone marrow nucleated cells. The cellular accumulation of LDL-ACR complex was much more than that of free ACR. The 3H-TdR incorporation test showed that the complex was more effective in the inhibition of DNA synthesis than that of the free drug. CONCLUSION: The potency of ACR to tumor cells increased and its toxicity to normal cells decreased when LDL was used as a carrier.

Aclarubicin↗