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Biomedical subjects

L Xu

Publications and source records attributed to L Xu.

At least 469 records · Page 26Linked to original sources
PubMed1998

[Influence of pravastatin therapy on expression of P-selectin].

OBJECTIVE: To study the mechanism of pravastatin enhancing atherosclerosis regression. METHODS: Patients with hypercholesterolemia were treated with pravastatin 10-20 mg/d for 4 and 8 weeks. The changes of blood cholesterol and platelet functions were examined. RESULTS: After 4 weeks and 8 weeks treatment, the expression of platelet membrane P-selectin was decreased from 748 +/- 154 molecular number(MN)/platelet to 478 +/- 110 MN/platelet and 378 +/- 119 MN/platelet, respectively, plasma P-selectin was decreased from 24.3 +/- 9.9 micrograms/L to 16.8 +/- 4.5 and 16.1 +/- 4.0 micrograms/L, respectively, correlative with the lowering of blood cholesterol. Platelet P-selectin was positively correlated with plasma P-selectin(r = 0.8722). CONCLUSION: The early benefit of pravastatin in enhancing atherosclerosis regression was partly due to the improvement of platelet function.

Female↗
PubMed1998

[Studies on the committed differentiation of CD34+ hematopoietic progenitor cells].

OBJECTIVE: To elucidate the capacity of different hematopoietic growth factors (HGFs) combinations for inducing CD34+ cells to proliferate and differentiate committedly to granulocytes, erythrocytes, megakaryocytes and dendritic cells (DC). METHODS: CD34+ cells were isolated from umbilical cord blood by using a high-gradient magnetic cell sorting system (MACS), and expanded with HGFs in a liquid culture system. Colony forming cells and antigen expression were studied by colony forming assays and FACS. RESULTS: Different combinations of HGFs, including SCF, IL-3, IL-6, GM-CSF, Epo and Tpo increased BFU-E, CFU-GM, CFU-MK and CD41a+ cells by 14.97 +/- 2.89 fold, 14.46 +/- 3.19 fold, 34.67 +/- 4.62 fold and 17.29 +/- 2.34 fold, respectively. Combination of HGFs allowed generation of a large number of DCs. Cultures of CD34+ cells with the combination of FLT-3 ligand + GM-CSF + IL-4 + TNF-alpha yielded 24.28% +/- 2.14% CD1a+ cells, while the control cultures did not. CONCLUSION: It is possible to induce CD34+ cells to proliferate and differentiate committedly to different lineage of hematopoietic cells and DC.

Antigens, CD34↗
PubMed1998

[Resources investigation of Actinidia in Hunan Province].

Based on the resources investigation and taxonomic research on the plants of Actinidia in Hunan Province, 15 species and 5 varieties together with their distribution and utilization are reported. A key is set forth according to the differences among the above species and varieties.

China↗
PubMed1998

[Construction and secretory expression of single-chain Fv fragment M97 with therapeutic potential against tumor invasion and metastasis].

OBJECTIVE: To manufacture single chain Fv antibody fragment for cancer targeting therapy. METHODS: Based on recombinant phage display techniques, the construction, screening and expression of functional single-chain Fv fragment (scFv) from murine hybridoma C2H5 which secretes antibody specifically binding to (92 kD) type IV collagenase were performed. By RT-PCR for VH and VL genes, assembly of scFv genes and cloning into phagemid pCANTAB5E, transformation of TG1 cells and M13KO7 helper phage rescue, a recombinant phage scFv library with titre of 5 x 10(9) pfu/ml was established. Panning against immobilized type IV collagenase (92 kD) was performed by one round. Finally, 30 antigen-positive recombinant phage clones were isolated and identified by ELISA. RESULTS: DNA sequencing result showed that the entire gene of scFv against type IV collagenase (92 kD) designated as scFv-M97 is 732 bp, consisting of the 351 bp VH gene encoding 117 amino acids, the 336 bp VL gene encoding 112 amino acids and a 45 bp linker encoding (Gly4Ser)3. The antigen-positive phage with titre of 10(10) pfu/ml was used to infect HB2151 cells in which soluble scFv was expressed. After induction of Lac promotor by 1 mM IPTG for 20 h, the scFv-M97 yield of HB2151 in SBA medium is about 2 micrograms/ml. Immuno-blot indicated that the 27 kD scFv-M97 retained the affinity and specificity of the original intact antibody to type IV collagenase (92 kD). CONCLUSIONS: Single chain antibody scFv-M97 expressed by secretion was successfuly produced. As type IV collagenase plays an important role in tumor invasion and metastasis by the mechanism of proteolytic degradation of type IV collagen in the basement membrane, scFv-M97 may have therapeutic potential against tumor invasion and metastasis.

Amino Acid Sequence↗
PubMed1998

[Chemical constituents of Rheum wittrochii Lundstr(II)].

OBJECTIVE: To study the chemical constituents in the root of Rheum wittrochii. METHOD: Chromatography and spectroscopic analysis to isolate and elucidate the chemical constituents in the plant. RESULT: Six compounds, namely 3, 5-dihydroxy-4'-methoxystilbene; 3, 5, 4'-tridroxystilbene; piceatannol; desoxyrhaponticin; piceatannol-4'-O-beta-D-glucopyranoside; 2, 5-dimethyl-7-hydroxychromone, have been isolated from ethyl ether and ethyl acetate fractions. CONCLUSION: These compounds were isolated from the title plant for the first time.

Drugs, Chinese Herbal↗
PubMed1998

[Chemical constituents of Conyza blinii Lévl].

OBJECTIVE: To study the chemical constituents in the air-dried part of Conyza blinii. METHOD: The constituent isolation was done by solvent-extraction together with column chromatography. Several methods, such as IR, 1HNMR, 13CNMR and MS, were used to determine the structures of the isolated constituents. RESULT: Three compounds were isolated from the air-dried part of Conyza blinii and identified as friedelinol, n-triacontanol and daucosterol on the basis of physical and chemical properties and spectroscopic analysis. CONCLUSION: These compounds have not been discovered previously in this plant.

Asteraceae↗
PubMed1998

[Identification of 12 species of hailong and haima by HPCE].

Twelve species of Hailong and Haima were analyzed by HPCE(high performance capillary electrophoresis) and significant differences among the species were found. The method is rapid, highly efficient and reproducible, thus providing experimental criteria for the qualitative identification of these two crude drugs.

Animals↗
PubMed1998

[Chemical constituents of Conyza blinii Lévl].

Five compounds were isolated from the aerial part of Conyza blinii. On the basis of physicochemical properties and spectroscopic analysis, they were identified as alpha-spinasterol, 5, 8-dihydroxy-7, 3', 4'-trimethoxyflavone, caffeic acid, quercetin and syringic acid. All these compounds were isolated from the plant of C. blinii for the first time.

Asteraceae↗
PubMed1998

[Identification of commercial Chinese medicine ziwan].

OBJECTIVE: Commercial samples of Ziwan have been investigated and identified to find out the original species in circulation. METHOD: Comparative histological and morphological identification. RESULT: The main original plant species are Aster tataricus, Ligularia fischeri, L. hodgsonii, L. intermedia, L. wilsoniana, L. sibirica var. araneosa, L. veitchiana and L. caloxantha. CONCLUSION: The root and rhizome of A. tataricus are used as Ziwan in most areas of China; but those of Ligularia species are used as Ziwan(named Shanziwan) in southwest, and part of northwest and northeast areas of China.

Asteraceae↗
PubMed1998

[Chemical constituents of Rheum wittrochii Lundstr(I)].

OBJECTIVE: To study the chemical constituents in the root of Rheum wittrochii. METHOD: Chromatography and spectroscopic analysis were used to isolate and elucidate the chemical constituents in the plant. RESULT: Six compounds, namely chrysophanol, physcion, emodin, chrysophanol-8-O-beta-D-glucopyranoside, physcion-8-O-beta-D-glucopyranoside and beta-sitosterol, have been isolated from petroleum ether and ethyl acetate fractions. CONCLUSION: All the above-cited compounds were isolated from the title plant for the first time, and anthraquinone compounds are some of the major constituents of R. wittrochii.

Anthraquinones↗
PubMed1998

[Cleft palate with problems of middle ears].

OBJECTIVE: To gain a clear idea of the function of middle ears and hearing loss in cleft palate. METHODS: 59 cleft palate cases, including 117 ears are investigated by tympanogram and hearing threshold. RESULTS: In 80.4% of patients the function of middle ears are abnormal. 59.4% ears are conductive hearing loss in various degrees. CONCLUSION: Function of middle ears in cleft palate should be regularly examined as early as possible. If it is secretory otitis media, the tympanostomy pressure equalization tubes should be inserted to compensate inadequate function of the eustachian tube so as to avoid adhesive otitis media. The methods for the prevention and reduction of the middle ear problems with cleft palate are also suggested.

Adolescent↗
PubMed1998

[Effects of acetylsalvianolic acid A on arachidonic acid metabolism in platelets].

Acetylsalvianolic acid A (ASAA) has been shown to be an antiplatelet compound. Our studies with RIA showed that: at the dosage of inhibiting platelet aggregation, ASAA was found to inhibit the formation of cyclooxygenase pathway metabolites TXB2 in platelets. In addition, ASAA was also shown to promote the formation of 6-keto-PGF1 alpha in rabbit aortic rings in vitro. The above results suggest that ASAA may inhibit the proaggregator TXA2 formation, promote mildly the antiaggregator PGI2 generation and probably, whereby, exert its antiplatelet activity.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

[Molecular genetic marker identification of traditional Chinese drug hippocampus].

Ancient DNA technique was used to extract DNA from 5 species of Chinese traditional drugs Hippocampus. The 12S rRNA gene fragment and cytochrome b gene fragment were amplified from DNA extract using Polymerase Chain Reaction (PCR) method. Restriction Fragment Length Polymorphism (RFLP) analysis and DNA sequence analysis were performed. The RFLP analysis method can identify 2 species of Hippocampus. The molecular genetic markers produced by DNA sequence method can identify all 5 species of Hippocampus. This method will be valuable for the identification of other animal drugs.

Cytochrome b Group↗
PubMed1998

[Molecular identification of the Chinese drug turtle shells].

This paper reports a new method to identify the Chinese drug turtle shells using PCR product direct sequencing method. DNA was extracted from tissues of the Chinese three-keeled pond turtle Chinemys reevesii and 20 other species of turtles occurring in China and Southeast Asian countries. One hundred and ten base pairs of mitochondrial 12S rRNA gene fragment were amplified from the extract using PCR technique and obtained sequences. These sequences were used to construct 12S rRNA gene fragment sequence database for the 21 turtle species. Comparison of these sequences indicated that the sequence from the Chinese three-keeled pond turtle is different from that of all the other 20 turtle species. The sequence divergence is 3.7-15.7%. DNA was extracted from 0.1-0.5 g of shell from 19 turtle shells provided by the Jiangsu Institute for Drug Control and 12S rRNA gene fragment was amplified and sequenced. Comparison of the sequences from the 19 turtle shells and 12S rRNA gene fragment sequence database indicated that only 3 samples are shells of the Chinese three-keeled pond turtle specified in the Phamacopoeia of the People's Republic of China and the others are substitutes. The technique used in the present paper was found to be effective and reliable for the identification of turtle shells.

Animals↗
PubMed1998

[Sequencing of Cyt b gene fragments and PCR identification of "jinqian baihuashe" (Bungarus parvus) and its adulterants].

DNAs extracted from both "Jinqian Baihuashe" (Bungarus parvus) and its adulterants and original animals of the crude snake drugs were used as templates for Cyt b gene fragment amplification. The sequence data of the fragments showed that the differences of the sequence between Bungarus parvus and its adulterants were far greater than that between intraspecific variations of Bungarus parvus. Therefore, the Cyt b gene fragment was a good molecular genetic marker for the authentication of Bungarus parvus. On the basis of the sequence data, a pair of specialized primers, BuL-1 and BuH-1 was designed for the PCR identification of Bungarus parvus. The effectiveness of the primers were examined at a series of anneal temperatures. The results showed that Bungarus parvus samples could be absolutely distinguished when the anneal temperatures were 60 degrees C-65 degrees C, whereas no incorrect or missing discrimination was found at these temperatures. The results also showed that the powder of Bungarus parvus which was mixed with powders of three other crude snake drugs may be detected by the PCR identification. This indicates that PCR identification may be a new method for examining the compositions of Chinese patent medicine.

Animals↗
PubMed1998

[Scanning electron microscope observation and image quantitative analysis of Hippocampi].

The "scale-like projects" on the derma of 3 species of Hippocampi, H. kuda Bleerer, H. trimaculatus Leach and H. japonicus Kaup were observed by scanning electron microscope (SEM). Results showed that some characteristics such us size, shape and type of arrangement of the "scale-like projects" can be considered as the evidence for microanalysis. Image quantitative analysis of the "scale-like project" was carried out on 45 pieces of photograph using area, long diameter, short diameter and shape factor as parameters. No difference among the different parts of the same species was observed, but significant differences were found among the above 3 species.

Animals↗