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Biomedical subjects

Z L Chen

Publications and source records attributed to Z L Chen.

At least 55 records · Page 3Linked to original sources
PubMed2000

Protective effects of bilobalide on amyloid beta-peptide 25-35-induced PC12 cell cytotoxicity.

AIM: To study the effect of bilobalide, a terpene extracted from the leaves of Ginkgo biloba, on beta-amyloid peptide fragment 25-35 (A beta 25-35)-induced PC12 cell cytotoxicity. METHODS: 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assay were used to measure the viability of PC12 cells. Thiobarbituric acid-reactive substances were measured to determine lipid peroxidation of cells. Antioxidant enzymes in PC12 cells were detected. RESULTS: Treatment of PC12 cells with A beta 25-35 (100 mumol.L-1) for 24 h caused a great decrease in cell viability (P < 0.01 compared with control). Bilobalide 25-100 mumol.L-1 dose-dependently attenuated the cytotoxic effect of A beta 25-35. Bilobalide also inhibited A beta 25-35 (100 mumol.L-1)-induced elevation of lipid peroxidation and decline of antioxidant enzyme activities. CONCLUSION: Bilobalide protected PC12 cells from A beta 25-35-induced cytotoxicity.

Amyloid beta-Peptides↗
PubMed2000

Bilobalide promotes expression of glial cell line-derived neurotrophic factor and vascular endothelial growth factor in rat astrocytes.

AIM: To study the effects of bilobalide on the expression of glial cell line-derived neurotrophic factor (GDNF) and vascular endothelial growth factor (VEGF) in rat astrocytes in vitro. METHODS: Semiquantification polymerase chain reaction (SQ-PCR) was used to investigate GDNF and VEGF mRNA expression in the astrocytes after bilobalide (5, 15, 50, 100 mumol.L-1) treatment. Immunohistochemistry method was used to detect GDNF and VEGF protein expression in cells treated with bilobalide 50 mumol.L-1 for 24 h. RESULTS: GDNF and VEGF mRNA increased markedly after astrocytes were treated with bilobalide 50 mumol.L-1 for 12 h. GDNF and VEGF protein were detected in the cytoplasm of astrocytes after the cells were treated with bilobalide 50 mumol.L-1 for 24 h. CONCLUSION: Bilobalide induced GDNF and VEGF expression in the cultured astrocytes.

Animals↗
PubMed2000

Protective effect of bilobalide against nitric oxide-induced neurotoxicity in PC12 cells.

AIM: To examine the effects of bilobalide on nitric oxide-induced neurotoxicity in pheochromocytoma-derived PC12 cells (PC12 cells). METHODS: PC12 cell survival was monitored by LDH release and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assays. Superoxide dismutases (SOD) and catalase (CAT) activities were measured based on their abilities to inhibit the oxidation of epinephrine by the xanthine-xanthine oxidase system or to decompose H2O2 respectively. The content of malondialdehyde (MDA) was measured by a fluorometric assay to indicate the lipid peroxidation. RESULTS: 3-Morpholinosydnonimine (SIN-1, 50-300 mumol.L-1) induced PC12 cell damage. After the cells had been pretreated with 10 mumol.L-1 bilobalide for 24 h, the cell viability was increased to 91% +/- 30% from 52% +/- 14% in SIN-1 alone group. Moreover, the activities of SOD and CAT were increased after cells were treated with bilobalide. CONCLUSION: The NO-induced neurotoxicity can be protected by bilobalide in PC12 cells. The bilobalide-induced increase in SOD and CAT activities may serve as one of the mechanisms underlying the neuroprotective effect of bilobalide.

Animals↗
PubMed2000

[Studies on the flavonol glycosides from the seeds of Vaccaria segetalis].

OBJECTIVE: To study the chemical constituents of the seeds of Vaccaria segetalis. METHOD: Chromatography and spectral analysis were used to isolate the constituents and elucidate their structure. RESULT: Three compounds were isolated from alcohol extract of the seeds of V. segetalis, and identified as apigenin-6-C-arabinosylglucoside(1), apigenin-6-C-glucosylglucoside(2), vaccarin(3). CONCLUSION: Compound 1 and 2 were isolated from the seeds of this plant for the first time.

Apigenin↗
PubMed2000

[Studies on chemical constitutents in seeds of Allium tuberosum Rottl].

OBJECTIVE: To study the chemical constituents in the seed of Allium tuberosum. METHOD: Chromatography and spectral analysis were used to isolate the constituents and elucidate their structures. RESULT: Five compounds were isolated from the alcohol extracts of the seeds and identified as nicotianoside C, (22S)-cholest-5-ene-1 beta, 3 beta, 16 beta, 22-tetrol-1-O-alpha-L-rhamnopyranosyl-16-O-beta-D-glucopyranoside, daucosterol, adenosine and thymidine. CONCLUSION: All the compounds were isolated from the seed of this plant for the first time.

Adenosine↗
PubMed2000

[Detection of EBV-DNA, EBNA2 and LMP-1 in tumor tissues of han and uygur patients with nasopharyngeal carcinoma in Xinjiang].

OBJECTIVE: To investigate the possible differences of human nasopharyngeal carcinogenesis between Han and Uygur patients in xinjiang. METHOD: Detection of EBV-DNA, EBNA2 and LMP-1 in tumor tissues of 73 patients (Han 41, uygur 32) with nasopharyngeal carcinoma (NPC) were performed by PCR and immunohistochemistry. RESULT: Tho positive rate of EBV-DNA, EBNA2 expression was 48.2%(20/41), 43.9% (18/41) in Han and 59.3%(19/32), 43.7%(14/32) in Uygur respectively, no significant difference was found (P > 0.05). Expression of LMP-1 in NPC, in both positive and negative EBV-DNA specimens, was higher in Uygur (78.9%) than that in Han (40%) (P < 0.05), CONCLUSION: The EBV infection may involve in nasopharyngeal carcinogenesis in xinjiang; the LMP-1 of EBV could be a more critical factor in malignant transformation of normal nasopharyngeal epithelium in uygur people than in han Chinese.

Adolescent↗
PubMed1999

Neuronal death and blood-brain barrier breakdown after excitotoxic injury are independent processes.

Neuronal damage in the CNS after excitotoxic injury is correlated with blood-brain barrier (BBB) breakdown. We have used a glutamate analog injection model and genetically altered mice to investigate the relationship between these two processes in the hippocampus. Our results show that BBB dysfunction occurs too late to initiate neurodegeneration. In addition, plasma infused directly into the hippocampus is not toxic and does not affect excitotoxin-induced neuronal death. To test plasma protein recruitment in neuronal degeneration, we used plasminogen-deficient (plg(-/-)) mice, which are resistant to excitotoxin-induced degeneration. Plasminogen is produced in the hippocampus and is also present at high levels in plasma, allowing us to determine the contribution of each source to cell death. Intrahippocampal delivery of plasminogen to plg(-/-) mice restored degeneration to wild-type levels, but intravenous delivery of plasminogen did not. Finally, although the neurons in plg(-/-) mice do not die after excitotoxin injection, BBB breakdown occurs to a similar extent as in wild-type mice, indicating that neuronal death is not necessary for BBB breakdown. These results indicate that excitotoxin-induced neuronal death and BBB breakdown are separable events in the hippocampus.

Animals↗
PubMed1999

Effect of 12-O-tetradecanoyl-phorbol ester and incisional wounding on neuropsin mRNA and its protein expression in murine skin.

The expression of neuropsin mRNA in vivo in mouse skin was examined by in situ hybridization and Northern blotting under stimulated conditions. Two kinds of epidermal stimuli, a topical application of a chemical tumor promoter and incisional wounding, were used. A single topical application of 12-O-tetradecanoyl-phorbol 13-acetate induced epidermal hyperplasia and simultaneously induced an extensive increase in neuropsin mRNA in the suprabasal cells. A full-thickness skin incision also induced a profound increase in neuropsin mRNA in the suprabasal cells surrounding the wound but not in actively proliferating basal cells. The increases in neuropsin mRNA occurred rather late and were limited to the site of drug application or around the incision. Interestingly, neuropsin mRNA was not expressed in the epithelial tongue migrating toward the wound during re-epithelialization. Thus, neuropsin might participate in accelerated epidermal differentiation rather than in the proliferation or migration of keratinocytes in the wound.

Animals↗
PubMed1999

Three new diterpenoids from Mallotus apelta Muell.Arg.

Three new diterpenoids, 10-hydroxy-cembrene-5-one, 6-hydroxy-cembrene-5,10-dione and 2alpha,4beta,15,16-tetrahydroxyl-dolabradane were isolated from the petroleum ether fraction of the alcoholic extract of Mallotus apelta Muell.Arg. Their structures were determined by spectral methods.

Diterpenes↗
PubMed1999

Open-heart surgery in 48 patients via a small right anterolateral thoracotomy.

To limit the trauma to the chest and to achieve a pleasing cosmetic result, we used 2 types of right anterolateral thoracotomy in 48 patients who required open-heart surgery: 1 was a curved incision along the lower edge of the right breast in women with developed breasts; the other was a slanted incision for men and children. These surgical procedures took place between July 1996 and November 1997. Intraoperatively, a right atriotomy was used to repair 11 atrial septal defects and 11 ventricular septal defects, 2 combined atrial and ventricular septal defects, 1 case of a single atrium, and 1 partial atrioventricular canal. A right ventricular outflow tract incision was used to repair 7 ventricular septal defects and 7 ruptured aortic sinus aneurysm. A combination of a right atriotomy and right ventricular outflow tract incision was used for 2 repairs of combined atrial and ventricular septal defects, 3 radical corrections of tetralogy of Fallot, and 2 radical corrections of trilogy of Fallot. A combined right and interatrial septal incision was used for 6 mitral valve replacements and 1 mitral valvuloplasty. Smooth bypass cannulation and satisfactory intracardiac exposure were achieved with the right anterolateral thoracotomy. There was no complication or mortality directly related to the incision. We believe that the right anterolateral thoracotomy is safer and more effective than the median sternotomy for many common congenital and acquired heart diseases. The thoracotomy causes less trauma and results in a cosmetic appearance that is more acceptable to the patient.

Adolescent↗
PubMed1998

A 3D-QSAR study on ginkgolides and their analogues with comparative molecular field analysis.

Comparative molecular field analysis (CoMFA), a three-dimensional quantitative structure-activity relationship (3D-QSAR) paradigm was used to study the correlation between the physicochemical properties and the in vitro bioactivities of ginkgolide analogues. The correlation derived from CoMFA analysis has a good predictive capability. Based on the result of CoMFA analysis, we designed some compounds. Pharmacological assay indicated that three of these new designed compounds are 2 and 4 times more potent than that of ginkgolides.

Diterpenes↗
PubMed1998

The 42K protein of rice dwarf virus is a post-translational cleavage product of the 46K outer capsid protein.

The outer capsid protein (P8) heterogeneity of rice dwarf virus (RDV) exists not only in purified virus particles, but also in RDV-infected rice, transgenic rice expressing P8, E. coli expression of P8 product and the in vitro translation products of S8. N-terminal amino acid sequencing revealed that P8 is a cleavage product of P8'. The cleavage occurs specifically at the residues of Asp362 and Pro363. The function of the proteolytic processing is unknown.

Capsid↗
PubMed1998

5-Lipoxygenase and cyclooxygenase-1 inhibitory active compounds from Atractylodes lancea.

Lipophilic extracts of Atractylodes lancea rhizomes exhibited potent inhibitory activities in 5-lipoxygenase [IC50 (5-LOX) = 2.9 micrograms/mL (n-hexane extract)] and cyclooxygenase-1 [IC50 (COX-1) = 30.5 micrograms/mL (n-hexane extract)] enzymatic assays. Bioactivity-guided fractionation of the n-hexane extract led to the isolation of a new compound atractylochromene (1), a potent inhibitor in both test systems [IC50 (5-LOX) = 0.6 microM, IC50 (COX-1) = 3.3 microM]. Also obtained was 2-[(2E)-3,7-dimethyl-2,6-octadienyl]-6-methyl-2,5-cyclohexadiene-1 ,4-dione (2), which showed a selective inhibitory activity against 5-LOX [IC50 (5-LOX) 0.2 microM, IC50 (COX-1) 64.3 microM]. The sesquiterpene atractylon (3) and the coumarin osthol (4) turned out to be moderate but selective 5-lipoxygenase inhibitors. Atractylenolides I (5), II (6), and III (7) showed no significant inhibitory effects for either enzyme. Structures were established by spectral data interpretation.

Animals↗
PubMed1998

Expression of neuropsin mRNA in the mouse embryo and the pregnant uterus.

Neuropsin is a novel serine protease whose mRNA is expressed in the mouse central nervous system. We examined the expression of neuropsin mRNA during embryonic development using Northern and in situ hybridization in non-neural tissues. The pregnant uterus showed strong expression of neuropsin mRNA, whereas the nonpregnant uterus did not express this mRNA. Expression was first detected in the primary decidual zone at 5.5 days post coitum and was maximized at 10 days post coitum, decreasing remarkably thereafter. During mouse organogenesis, neuropsin expression was observed in the developing heart, lung, thymus, pituitary, choroid plexus, and epithelial linings of the skin, oral cavity, tongue, esophagus, and forestomach. In adult mouse organs, neuropsin mRNA was expressed in epithelial tissues covered by keratinocytes with moderate density, whereas low expression was observed in lung, thymus, and spleen. Neuropsin mRNA expression in developing organs and adult keratinocytes suggests that neuropsin is associated with extracellular matrix modifications and cell migrations.

Animals↗
PubMed1998

Effects of ciclosporin on whole blood chemiluminescence of renal transplant patients.

AIM: To examine the possible inhibitory role of ciclosporin (Cic) on luminol-dependent chemiluminescence (CL) of whole blood in renal transplant patients. METHODS: Luminol-dependent CL was used to measure active oxygen species generation in respiratory burst of whole blood stimulated by zymosan A. Fluorescence polarization immunoassay was used to monitor the blood concentration of Cic. RESULTS: CL values of Cic group (n = 50) decreased in comparison with those of normal group (n = 10) (P < 0.01). The blood concentration of Cic was negatively related to CL value (P < 0.01). The serum of renal transplant patients directly inhibited respiratory burst of peritoneal macrophages of rats in a concentration-dependent manner. CONCLUSION: Cic inhibits the phagocytic activity of neutrophils in renal transplant patients.

Adult↗
PubMed1998

[Effects of O-(4-ethoxyl-butyl)-berbamine on isolated frog hearts].

AIM: To study the effects of O-(4-ethoxyl-butyl)-berbamine (EBB) on isolated frog heart. METHODS: The isolated frog hearts were prepared with Straub's method; heart contractions were recorded using LMS-2A recorder by tonotransducer. RESULTS: EBB 1-100 mumol.L-1 caused concentration-dependent increase in systolic and diastolic activities, but did not alter the heart rate. EBB 250-500 mumol.L-1 slowed the heart beats and caused ventricular asystole. Cimetidine 10 mumol.L-1 or prazosin 100 mumol.L-1 did not inhibit the positive inotropic action of EBB. Whereas verapamil 0.01 mumol.L-1 antagonized the positive inotropic action of EBB. EBB enhanced positive inotropic action of CaCl2. The action of EBB was slower but longer than caffeine or isoproterenol. At room temperature (21.0 +/- 0.5) degree C, however, the onset of oubain was slower, but the duration of its peak action was longer, than EBB. CONCLUSION: The positive inotropic action of EBB was, at least partially, via promoting the inward current of [Ca2+]o, rather than increasing the intracellular Ca2+ release.

Alkaloids↗