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Biomedical subjects

S Xu

Publications and source records attributed to S Xu.

At least 199 records · Page 11Linked to original sources
PubMed2000

[Improving memory effects of eel oil capsule on memory obstruction of mice hurt by anisodine].

The effects of eel oil capsule on memory obstruction of mice were observed in step-down test, step-through test, Y-maze test and Japanese labyrinth test. The results indicated that the eel oil capsule treating group with dosages of 0.234, 0.702 and 2.106 g/kg markedly enhance the acquirement, strengthing and reappearance of memory, having the functions of improving brain memory hurt by Anisodine.

Animals↗
PubMed2000

[Protective effect of total paeony glycoside against cerebral ischemia-reperfusion injury in mice].

OBJECTIVE: To investigate actions of Total Paeony Glycoside (TPG) on cerebral ischemia-reperfusion model in mice. METHODS: The cerebral ischemia-reperfusion models induced by lagation of bilateral common carotid arteries incompletely were used. RESULTS: It was found that TPG could improve the learning and memory capacity of model mice in step down test. TPG significantly reduced the decrease of superoxide dismutase(SOD), inhibited the increase of nitric oxide(NO) and lessened the level of malondialdehyde(MDA) in model mice. 75 mg.kg-1 TPG also reduced the decrease of lactate dehydrogenase (LDH) in cerebrum remarkedly. CONCLUSION: It is suggested that TPG possess obvious protective effects against cerebral ischemia-reperfusion mice.

Animals↗
PubMed2000

[Preparation of tea polyphenols sustained-release microcapsule].

With ethycellulose (EC) as matrix tea polyphenols (TP) microcapsule was prepared by using emulsion solvent evaporation technique. Effect of preparation condition on size and drug entrapment efficiency of microcapsule was investigated. We also investigated the drug entrapment effect of microcapsule. The result showed that the tawny microcapsule with highly porous surface was obtained by using polyvinyl alcohol (PVA) and sodium dodccyl sulate (SDS) as dispersant. The stirring rate, polymer concentration and drug payload affected the size and drug entrapment efficiency of microcapsule. The matrix and preparation method do not damage the ingredient of TP. The microcapsule can improve the stability of TP and sustain TP released.

Capsules↗
PubMed2000

[Effect of xanthone from Canscora lucidissima on cultured myocytes anoxia-reoxygenation injuries].

The anoxia/reoxygenation model of cultured neonatal rats myocardial cells were developed, according to Laarse's method: anoxia and glucose deficiency for 60 min followed by reoxygenation and re-exposure to glucose for 30 min. The results showed that the survival rate of myocardial cells in the anoxia group was significantly decreased, release of lactate dehydrogenase (LDH) from myocytes was increased and membrane fluidity was decreased, all the changes were much more severe in the reoxygenation group. 30 min before anoxia, addition of xanthones: 1,8-dihydroxy-3, 5-dimethoxyxanthone, 1-hydroxy-3,5-dimethoxyanthone and 1-hydroxy-3,7,8-trithoxyxanthone, isolated from Canscora lucidissima increased the rate of myocardial cells and membrane fluidity, decreased the release of LDH. These results suggested that xanthone may provide some protective effects on the anoxia/reoxygenation damages on myocardium.

Animals↗
PubMed2000

[Isolation and identification of a new long-chain tetrahydroxyamide].

A novel long chain tetrahydroxyamide compound (C42H85NO5, mp 178-180 degrees C) has been isolated from Polymastia sobustia collected from the South China Sea. On the basic of the spectral data of IR, MS, 1H NMR, 13C NMR, DEPT and chemical way, the compound was identified as N-(1-hydroxymethyl-2,6-dihydroxyl) heptadecyl-5-hydroxyltetracosanamide, sobustiamide.

Amides↗
PubMed2000

[Effects of oxidized LDL, hypoxia, and 5-hydroxytryptamine on 5-HT2A receptor and intracellular free Ca2+ in cultured vascular smooth muscle cells].

OBJECTIVE: To investigate the mechanisms of this hyperreactivity, the effects of oxLDL, hypoxia, and 5-HT (the relative factors inducing arteriosclerosis) on 5-HT2A receptor, receptor gene expression and intracellular free Ca2+ were observed in cultured rat aortic smooth muscle cells (ASMC). METHODS: ASMC underwent 50 micrograms/ml oxLDL 8 hours, 2% hypoxia 24 and 48 hours, 10 mumol/L 5-HT 30 min. 5-HT2A receptor, 5-HT2A receptor mRNA and [Ca2+]i of ASMC were estimated by radiobinding assay, RT-PCR and Southern blot method, and confocal laser scanning mode separately. RESULTS: After oxLDL, hypoxia, 5-HT pretreatment, 5-HT2A receptor of ASMC showed significant up-regulation. Both 5-HT2A receptor mRNA expression and 5-HT-induced [Ca2+]i of ASMC increased markedly after oxLDL, hypoxia pretreatment. CONCLUSIONS: 5-HT2A receptor up-regulation and cell [Ca2+]i increase of ASMC induced by oxLDL, hypoxia, and 5-HT may play a role in vascular hyperreactivity induced by 5-HT in atherosclerosis arteries.

Animals↗
PubMed2000

[Determination of trace amounts of copper by flow injection vapor generation AAS].

A method for the determination of copper by FI-VGAAS (flow injection vapor generation atomic absorption spectrometry) was developed. The sample solution containing trace amounts of o-phenanthroline and 0.1 mol.L-1 HNO3 was carried out by carrier of 0.1 mol.L-1 HNO3 and merged with sodium tetrahydroborate solution to produce the vapor species of copper, which got separation in gas-liquid separator and was detected in a quartz tube atomizer at 1000 degrees C. A detection limit of 1.8 micrograms.L-1 (3 sigma) of copper was obtained with a sampling frequency of 144/h using a sample volume of 500 microL. The precision RSD was 2.6% (n = 11) at the 100 micrograms.L-1 copper. The method was applied to the analysis of human hair and rice standard reference samples, the results were in good agreement with certified values.

Borohydrides↗
PubMed2000

[Sequential injection vapor generation atomic absorption spectrometric determination of mercury and arsenic].

A sequential injection vapor generation atomic absorption spectrometric (SI-VGAAS) method for the determination of mercury and arsenic was developed, characterized by reagent merging using a double-syringe pump and a multi-position selector valve. A sample throughput of 120 h-1 was achieved with 500 microL sample with a precision of 2.2% for mercury at 8.0 micrograms.L-1 (n = 11) and 1.4% for arsenic at 6.0 micrograms.L-1 (n = 11) levels and a detection limit of 0.15 microgram.L-1 for mercury and 0.07 microgram.L-1 for arsenic. The method was applied to the analysis of geochemical standard reference material GSS-5, and good agreement with the certified values were obtained.

Arsenic↗
PubMed2000

[Study on the IR and UV dual-spectrum radiation].

The article gives a method to produce dual spectrum radiation in IR and UV. Relying on theoretical analysis, the relative data are computed, some atomic materials are selected and added to a double-base propellants. When the UV pyrotechnics is ignited together with traditional IR pyrotechnics, the spectrum of IR and UV is emitted at the same time. The final measuring curves show that all results are satisfying.

English Abstract↗
PubMed2000

[Study on the photoinduced-color changing about novel azobenzocrown ether derivatives 16ABC-OH and 16ABC-NH2 in water solution and Langmuir-Blodgett film].

Two kinds of azobenzocrown ether derivation 16ABC-OH and 16ABC-NH2 have been synthesized, and their photoinduced color changing phenomena has been investigated in water solution, the reaction of 16ABC-OH is the photochemical Cis-trans-isomerization, and it is a first-order reaction, but the reaction of 16ABC-NH2 photochemical Cis-trans-isomeriation is very complex; and it is not a first-order reaction. In Langmuir-Blodgett film of 16ABC-OH, there is not molecular self-assembly phenomenon, the part of Cis-16ABC-OH become to iso-16ABC-NH2, but in the film, 16ABC-NH2 form H-Polymer by self-assembly, and the photochromic Cis-trans-isomerization is forbidded.

English Abstract↗
PubMed1999

PHR1 encodes an abundant, pleckstrin homology domain-containing integral membrane protein in the photoreceptor outer segments.

We cloned human and murine cDNAs of a gene (designated PHR1), expressed preferentially in retina and brain. In both species, PHR1 utilizes two promoters and alternative splicing to produce four PHR1 transcripts, encoding isoforms of 243, 224, 208, and 189 amino acids, each with a pleckstrin homology domain at their N terminus and a transmembrane domain at their C terminus. Transcript 1 originates from a 5'-photoreceptor-specific promoter with at least three Crx elements ((C/T)TAATCC). Transcript 2 originates from the same promoter but lacks exon 7, which encodes 35 amino acids immediately C-terminal to the pleckstrin homology domain. Transcripts 3 and 4 originate from an internal promoter in intron 2 and either include or lack exon 7, respectively. In situ hybridization shows that PHR1 is highly expressed in photoreceptors, with lower expression in retinal ganglion cells. Immunohistochemistry localizes the PHR1 protein to photoreceptor outer segments where chemical extraction studies confirm it is an integral membrane protein. Using a series of PHR1 glutathione S-transferase fusion proteins to perform in vitro binding assays, we found PHR1 binds transducin betagamma subunits but not inositol phosphates. This activity and subcellular location suggests that PHR1 may function as a previously unrecognized modulator of the phototransduction pathway.

Alternative Splicing↗
PubMed1999

Calcium signaling induces acquisition of dendritic cell characteristics in chronic myelogenous leukemia myeloid progenitor cells.

Effective host T lymphocyte sensitization to malignant cells depends on successful antigen presentation. In this study, we examined the capacity of malignant myeloid progenitor cells of patients in the chronic phase of chronic myelogenous leukemia (CML) to acquire characteristics of activated dendritic cells (DCs) after intracellular calcium mobilization, thereby bypassing a need for third-party antigen-presenting cells. Treatment of purified CD33(+) CML cells from 15 patients with calcium ionophore (CI) consistently resulted in de novo expression of the costimulatory molecules CD80 (B7.1) and CD86 (B7.2), CD40 and the DC-specific activation marker CD83, as well as marked up-regulation of MHC class I and II molecules and the adhesion molecule CD54. Most of these changes occurred within 24 hr of treatment. Morphologically, CI-treated CML cells developed long dendritic projections similar to those seen in mature DCs. Functionally, CI-treated CML cells provided stimulation of allogeneic T lymphocytes 10- to 20-fold that of untreated CML cells or untreated monocytes. Fluorescent in situ hybridization of CI-activated CML cells confirmed their leukemic origin by displaying the typical bcr/abl fusion signal. No difference in bcr/abl translocation percentages between untreated and CI-treated CML nuclei was observed. These observations indicate that calcium mobilization may constitute a valuable approach for rapidly and reliably generating CML-derived DCs for immunotherapy of CML.

Antigens, CD↗
PubMed1999

Effect of steroidal saponins of Anemarrhenae rhizoma on superoxide generation in human neutrophils.

Effect of six steroidal saponins isolated from Anemarrhenae rhizoma on superoxide generation in human neutrophils was investigated. The steroidal saponins examined were anemarrhenasaponin-I (An-I), anemarrhenasaponin-Ia (An-Ia), timosaponin B-I (TB-I), timosaponin B-II (TB-II), timosaponin B-III (TB-III) and timosaponin A-III (TA-III). An-I, An-Ia, and TB-III suppressed the superoxide generations induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) and arachidonic acid (AA) in a concentration-dependent manner, but enhanced that induced by phorbol 12-myristate 13-acetate (PMA). While TB-II also suppressed and enhanced the superoxide generations induced by fMLP and PMA, respectively, the compound significantly enhanced the AA-induced superoxide generation. TB-I enhanced the fMLP-induced superoxide generation in a low concentration range (peak at 40 microM), gave no effect on the PMA-induced superoxide generation and weakly enhanced the AA-induced superoxide generation. TA-III enhanced the fMLP-induced superoxide generation more than twice as much as that by TB-I in the same concentration range. However, TA-III enhanced the PMA-induced superoxide generation and most significantly suppressed the AA-induced superoxide generation.

Arachidonic Acid↗