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Biomedical subjects

F Chen

Publications and source records attributed to F Chen.

At least 127 records · Page 7Linked to original sources
PubMed2001

[Effect of estrogen on hemodynamics and vascular remodeling with Takayasu arteritis].

This study utilized Takayasu arteritis (TA) model to do the experiment in order to observe the remodeling of arterial geometry. Plasma estrogen, progesterone and products of nitrous oxide (NO2- and NO3-) were examined. Qualitative analyses of maximum (MAX), minimum (MIN) and mean (MEAN) velocity of blood flow, resistant index (PI), pulsatile index (PI), and shear stress (SS) of abdominal aorta were performed. The results showed that plasma estrogen, progesterone and products of nitrous oxide were respectively 1137.80 +/- 189.30 pg.ml-1, 14.10 +/- 1.61 micrograms.ml-1 and 195.78 +/- 53.01 mumol.L-1 in experiment group, whereas in control group, they were 34.74 +/- 10.20 pg.ml-1, 2.60 +/- 1.83 micrograms.ml-1 and 12.16 +/- 3.28 mumol.L-1 respectively, P < 0.01. In comparison of hemodynamic parameters of abdominal aorta, the MAX and MIN of experiment group were profoundly higher than those of control group. SS increased markedly in experiment group. The observation of arterial remodeling in vitro found wall thickening. The thickness of abdominal aortic wall and inside diameter of vessel cavity ratio (h/Di) was 0.6145 +/- 0.1654 in experiment group and 0.2151 +/- 0.0266 in control group, P < 0.01. The arterial collagen content in experimental group was significantly higher than that in control group. Hyperestrinemia gives rise to a series of hemodynamic alterations, influences vessel remodeling along with TA, and finally results in arterial stenosis, occlusion or aneurysms due to the constitutional composition of vascular wall reforming.

Animals↗
PubMed2001

[Determination of protocatechualdehyde in yu xue bi granula].

The content of Protocatechualdehyde in YuXueBi granula was determined by HPLC. The chromatographic column was packed with ODS-2 (particle size 5 microns). The mobile phase was MeOH-H2O-H3PO4(17:83:0.003) adjusted to pH 3 with N(C2H5)3. The detection wavelength was 280 nm. The velocity of flow was 1.0 ml/min. The average recovery rate was 96.14%, RSD was 1.16%. The method was simple and stable.

Benzaldehydes↗
PubMed2001

Smoking and bony union after ulna-shortening osteotomy.

We examined the relation between cigarette use and occurrence of delayed union and nonunion after ulna-shortening osteotomy for ulnar impaction syndrome. After obtaining the smoking history of 39 patients (40 wrists), we found that, compared with nonsmokers, smokers experienced longer healing times and more of them experienced healing delay and nonunion. Mean union rates were 7.1 months in smokers and 4.1 months in nonsmokers. Six smokers (30%) and no nonsmokers experienced delayed union or nonunion. Given the adverse effects of smoking on bony union, we recommend that smoking history be considered when selecting patients for ulna-shortening procedures.

Adult↗
PubMed2001

Reactive oxygen species and molecular mechanism of silica-induced lung injury.

Silica particles are considered to be fibrogenic and carcinogenic agents, but the mechanisms of disease initiation and progression are not fully understood. This article summarizes the literature on the generation of reactive oxygen species (ROS) directly from interaction of silica with aqueous medium and from silica-stimulated cells. This article also discusses the role of ROS in silica-induced lung injury, with particular focus on the silica-induced NF-kappaB activation, including the molecular mechanisms of its regulation, its possible attenuation, and its relationship to silica-induced generation of cyclooxygenase II and TNF-alpha.

Air Pollutants, Occupational↗
PubMed2001

Carcinogenic metals and NF-kappaB activation.

Epidemiological and animal studies suggest that several metals and metal-containing compounds are potent mutagens and carcinogens. These metals include chromium, arsenic, vanadium, and nickel. During the last two decades, chemical and cellular studies have contributed enormously to our understanding of the mechanisms of metal-induced pathophysiological processes. Although each of these metals is unique in its mechanism of action, some common signaling molecules, such as reactive oxygen species (ROS), may be shared by many of these carcinogenic metals. New techniques are now available to reveal the mechanisms of carcinogenesis in precise molecular terms. In this review, we focused our attentions on metal-induced signal transduction pathways leading to the activation of NF-kappaB, a transcription factor governing the expression of most early response genes involved in a number of human diseases.

Animals↗
PubMed2001

Cell apoptosis induced by carcinogenic metals.

Well-documented evidence suggests that environmental and occupational exposure of toxic metals or metal-containing compounds can cause a number of human diseases, including inflammation and cancer, through DNA damage, protein modifications, or lipid peroxidation. This mini-review addresses the mechanisms of cell death induced by some carcinogenic metals, including arsenic (III), chromium (VI) and vanadium (V). A possible contribution of reactive oxygen species to metal-induced cell death is also discussed.

Animals↗
PubMed2001

Cr (VI) increases tyrosine phosphorylation through reactive oxygen species-mediated reactions.

While Cr (VI)-containing compounds are well established carcinogens, the mechanisms of their action remain to be investigated. In this study we show that Cr (VI) causes increased tyrosine phosphorylation in human lung epithelial A549 cells in a time-dependent manner. N-acetyl-cysteine (NAC), a general antioxidant, inhibited Cr (VI)-induced tyrosine phosphorylation. Catalase, a scavenger of H2O2, sodium formate and aspirin, scavengers of hydroxyl radical (*OH), also inhibited the increased tyrosine phosphorylation induced by Cr (VI). SOD, an inhibitor of superoxide radical (O2*-), caused less inhibition. ESR study shows that incubation of Cr (VI) with the A549 cells generates *OH radical. The generation of radical was decreased by addition of catalase and sodium formate, while SOD did not have any inhibitory effect. Oxygen consumption measurements show that addition of Cr (VI) to A549 cells resulted in enhanced molecular oxygen consumption. These results indicate that Cr (VI) can induce an increase in tyrosine phosphorylation. H2O2 and *OH radicals generated during the process are responsible for the increased tyrosine phosphorylation induced by Cr (VI).

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

On the mechanism of Cr (VI)-induced carcinogenesis: dose dependence of uptake and cellular responses.

Cr (VI) compounds are widely used industrial chemicals and are recognized human carcinogens. The mechanisms of carcinogenesis associated with these compounds remain to be investigated. The present study focused on dose-dependence of Cr (VI)-induced uptake and cellular responses. The results show that Cr (VI) is able to enter the cells (human lung epithelial cell line A549) at low concentration (< 10 microM) and that the Cr (VI) uptake appears to be a combination of saturable transport and passive diffusion. Electron spin resonance (ESR) trapping measurements showed that upon stimulation with Cr (VI), A549 cells were able to generate reactive oxygen species (ROS). The amount of ROS generated depended on the Cr (VI) concentration. ROS generation involved NADPH-dependent flavoenzymes. Cr (VI) affected the following cellular parameters in a dose-dependent manner, (a) activation of nuclear transcription factors NF-kappaB, and p53, (b) DNA damage, (c) induction of cell apoptosis, and (d) inhibition of cell proliferation. The activation of transcription factors was assessed by electrophoretic mobility shift assay and western blot analysis, DNA damage by single cell gel electrophoresis assay, cell apoptosis by DNA fragmentation assay, and cell proliferation by a non-radioactive ELISA kit. At the concentration range used in the present study, no thresholds were found in all of these cell responses to Cr (VI). The results may guide further research to better understand and evaluate the risk of Cr (VI)-induced carcinogenesis at low levels of exposure.

Antioxidants↗
PubMed2001

Two tomato expansin genes show divergent expression and localization in embryos during seed development and germination.

Expansins are plant proteins that can induce extension of isolated cell walls and are proposed to mediate cell expansion. Three expansin genes were expressed in germinating tomato (Lycopersicon esculentum Mill.) seeds, one of which (LeEXP4) was expressed specifically in the endosperm cap tissue enclosing the radicle tip. The other two genes (LeEXP8 and LeEXP10) were expressed in the embryo and are further characterized here. LeEXP8 mRNA was not detected in developing or mature seeds but accumulated specifically in the radicle cortex during and after germination. In contrast, LeEXP10 mRNA was abundant at an early stage of seed development corresponding to the period of rapid embryo expansion; it then decreased during seed maturation and increased again during germination. When gibberellin-deficient (gib-1) mutant seeds were imbibed in water, LeEXP8 mRNA was not detected, but a low level of LeEXP10 mRNA was present. Expression of both genes increased when gib-1 seeds were imbibed in gibberellin. Abscisic acid did not prevent the initial expression of LeEXP8 and LeEXP10, but mRNA abundance of both genes subsequently decreased during extended incubation. The initial increase in LeEXP8, but not LeEXP10, mRNA accumulation was blocked by low water potential, but LeEXP10 mRNA amounts fell after longer incubation. When seeds were transferred from abscisic acid or low water potential solutions to water, abundance of both LeEXP8 and LeEXP10 mRNAs increased in association with germination. The tissue localization and expression patterns of both LeEXP8 and LeEXP10 suggest developmentally specific roles during embryo and seedling growth.

Cell Wall↗
PubMed2001

[The role of exogenous hRAR beta gene on the growth inhibition and differentiation induction of HL-60R Cells].

OBJECTIVE: To investigate the role of hRAR beta gene in HL-60R cells and in their response to retinoids. METHODS: By electroporation, the recombinant pcDNA3-hRAR beta plasmid was transfected into the hRNA beta gene not expressed human myleocytic leukemic cell line HL-60R. In the presence of RAR-selected agonist Ch55, the effect of RAR beta gene on HL-60R was studied by the efficiency of colony formation in soft agar, cell morphology NBT reduction assay and flow cytometry. RESULTS: The HL60R-hRAR beta cells with stable hRAR beta gene expression were obtained. The growth and colony formation in soft agar of HL60R-hRAR beta cells were remarkably reduced as compared with that of their parent cells, and the cells were induced into granulocytic differentiation by Ch55 treatment at 10(-7). CONCLUSION: The expression of exogenous hRAR beta gene in HL-60R cells could resume their sensitivity to retionoids in inhibiting cell proliferation and inducing granulocytic differentiation.

Cell Differentiation↗
PubMed2001

Chimera formation of platelet GP II b Bak a/b by intrauterine transplantation of fetal liver stem cells.

OBJECTIVE: To investigate whether artificial heterozygous chimeras of platelets can be established by intrauterine transplantation of fetal liver stem cells and evaluate its potential use for the treatment of Glanzmann thrombasthenia. METHODS: Platelet glycoprotein (GP) II b Bak a/b (or GP II b I le843Ser) was used as a genetic marker. A homozygous 16-week-old Bak a/a fetus (as donor) and a homozygous 16.5-week-old Bak b/b fetus (as recipient) were screened from 42 pregnant women hospitalized for abortion. PCR with allele specific primers and FOK I digestion based on PCR products were used. Aborted donor fetal liver cell suspensions were prepared and intrauterine transplantation was carried out by infusion of 4 ml fetal liver cells (22 x 10(5)) into the recipient umbilical vein under ultrasonic visualization. RESULTS: At gestation termination (abortion), 21 days after transplantation, chimera GP II b Bak a/b of the recipient were detected by FOK 1 digestion based on PCR from DNA and RT-PCR from platelet RNA. CONCLUSION: Intrauterine transplantation of fetal liver cell may provide an effective way for curing GT or other inherited diseases.

Adult↗
PubMed2001

Histochemical study of transmyocardial laser channels in dogs.

OBJECTIVE: Laser-induced myocardial injury was investigated in a canine transmyocardial laser revascularization model. METHODS: A total of 23 channels were created in the left ventricles of 5 animals with a CO2 laser. Four animals were sacrificed immediately and one at week 2. Lactate dehydrogenase and succinate dehydrogenase in channel regions were examined with a Nitro-BT method staining. RESULTS: Immediately after the procedure, laser channels and surrounding injured myocardium could be stratified from the center to the border into 5 concentric zones, i.e., vaporized zone, carbonized zone, enzyme-disappeared zone, enzyme-decreased zone and enzyme-concentrated zone. Two weeks later, the phenomenon disappeared. CONCLUSIONS: Immediately after transmyocardial revascularization, there is a ring of enzyme-concentrated zone at the outermost region of injured myocardium. Two weeks later, enzyme activities of reversibly injured myocytes appear to have recovered.

Animals↗
PubMed2001

[Subcellular distribution of daunorubicin in the P-glycoprotein-mediated multidrug-resistant cell line K562/ADR].

OBJECTIVE: To examine subcellular distribution of daunorubicin (DNR) in P-glycoprotein-mediated multidrug-resistant cell line K562/ADR and its relation to multidrug resistance. METHODS: The subcellular distribution of DNR in K562/ADR was studied by confocal scanning laser microscopy (CSLM), fluorometry, RT-PCR. Rhodamine 123, NBD-ceramide and neutral red as fluorescent probes to stain the mitochondria, Golgi apparatus and lysosomes respectively were used to identify the subcellular compartments wherein DNR was sequestered. Effect of verapamil, chloroquine and brefeldin A on DNR distribution and accumulation was examined. RESULTS: Compared with the drug-sensitive cell K562/S in which DNR fluorescence diffusely appeared in the nucleus and cytoplasm, DNR in K562/ADR cells was distributed to the perinuclear region and peripheral cytoplasm, It was scenty in the nucleus and other cytoplasmic regions, as suggested by the distribution of Rhodamine123. Only verapamil, but not chloroquine and brefeldin A, could markedly restore diffuse cytoplasmic and nuclear fluorescence distribution in the resistant cell line. CONCLUSION: Altered subcellular distribution of DNR in drug resistant cell line may participate in the generation of multidrug resistance in which P-glycoprotein plays an important role.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

[A study of injectable autologous tissue engineering cartilage].

OBJECTIVE: To study the regeneration of injectable autologous cartilage in New Zealand rabbits model. METHODS: Chondrocytes were harvested from auricle of New Zealand rabbits. The cells were mixed with sodium alginate (SA) and temperature dependent synthetic hydrogel (TDSH) to generate final cellular density of 50 x 10(9)/L, and then the chondrocytes-SA and chondrocytes-TDSH composites were injected into the dorsal subcutaneous tissue of New Zealand rabbits with form of autologous cells grafts respectively. The specimen and histology were observed in the process of cartilage fabrication in 4, 8, 12 weeks. RESULTS: Four weeks after injection, the hard knobbles were formed subcutaneously. Eight and twelve weeks after injection, the knobbles was much harder and showed the appearance of cartilage. In histological analysis, the immature cartilage can be observed after 4 weeks. In the eight and twelve weeks, the mature cartilage was formed and showed strong GAG positive expressed by safranine-O. CONCLUSIONS: Neocartilage could be regenerated through injection of alginate and synthetic hydrogel mixed with chondrocytes. Using tissue-engineering methods, Injectable cartilage may have great potential of clinical use in the future.

Animals↗
PubMed2001

[Human cytomegalovirus inhibits the proliferation of CFU-MK in vitro].

OBJECTIVE: To investigate the effect of human cytomegalovirus (HCMV) on the proliferation of colony forming unit-megakaryocyte (CFU-MK). METHODS: Semi-solid CFU-MK culture system was used to observe the effect of HCMV AD169 strain on CFU-MK growth of 20 cord blood samples. HCMV DNA and immediate early antigen (IEA) mRNA in CFU-MK were detected by in situ-polymerase chain reaction (IS-PCR) and reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: HCMV AD169 suppressed the differentiation and proliferation of CFU-MK in vitro significantly. The suppression was in a dose-dependent fashion. HCMV DNA was successfully detected in colony cells from viral infection group, and did the expression of HCMV IEA mRNA. CONCLUSION: HCMV AD169 can directly infect megakaryocyte progenitor and suppress their proliferation and differentiation.

Cell Proliferation↗