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Biomedical subjects

Feng Zhao

Publications and source records attributed to Feng Zhao.

59 records · Page 4Linked to original sources
PubMed2002

[Studies of influential factors in determination of Ca2+ by combination of FAAS with micro-column enrichment].

It have been studied that the influential factors in determination of calcium by combination of FAAS with micro-cell preconcentration. In order to the preconcentration, the ions can be adsorbed by the self-made electrochemical preconcentration micro-cell. Then the adsorbed ions instantly return into solution which is small in size and directly into FAAS. This method can greatly improve determination sensitiveness. The characteristic concentration and detection limit for the determination of Ca2+ can be improved with 1-2 order of magnitude, the characteristic concentration about 163 times. The results are satisfactory.

Adsorption↗
PubMed2000

Inhibitory Effects of Antioxidants on NF-KappaB Activation in Bovine Carotid Artery Endothelial Cells.

NF-Kappa B is one of important transcription factor, which plays an important role in many immune and inflammatory responses. A large variety of stimulus can induce the degradation of IKappa B-alpha, an inhibitor of NF-KappaB, leading to the activation and translocation of NF-KappaB into nuclei. In the present study, the effects of antioxidants on TNF-alpha-induced NF-KappaB activation were tested by using cultured bovine carotid artery endothelial cells. The degradation of IKappaB-alpha were checked by Western blot, and the nuclear translocation of NF-KappaB were tested by immunofluorescence. Our results showed that pyrrolidine dithio-carbamate (PDTC) completely inhibited IKappaB-alpha degradation and nuclear translocation of NF-KappaB induced by TNF-alpha, and other antioxidants also exhibited inhibitory activities on TNF-alpha-induced I B-alpha degradation.

Journal Article↗
PubMedDate not supplied

Effects of oxygen transport on 3-d human mesenchymal stem cell metabolic activity in perfusion and static cultures: experiments and mathematical model.

Human mesenchymal stem cells (hMSCs) have unique potential to develop into functional tissue constructs to replace a wide range of tissues damaged by disease or injury. While recent studies have highlighted the necessity for 3-D culture systems to facilitate the proper biological, physiological, and developmental processes of the cells, the effects of the physiological environment on the intrinsic tissue development characteristics in the 3-D scaffolds have not been fully investigated. In this study, experimental results from a 3-D perfusion bioreactor system and the static culture are combined with a mathematical model to assess the effects of oxygen transport on hMSC metabolism and proliferation in 3-D constructs grown in static and perfusion conditions. Cells grown in the perfusion culture had order of magnitude higher metabolic rates, and the perfusion culture supports higher cell density at the end of cultivation. The specific oxygen consumption rate for the constructs in the perfusion bioreactor was found to decrease from 0.012 to 0.0017 micromol/10(6) cells/h as cell density increases, suggesting intrinsic physiological change at high cell density. BrdU staining revealed the noneven spatial distribution of the proliferating cells in the constructs grown under static culture conditions compared to the cells that were grown in the perfusion system. The hypothesis that the constructs in static culture grow under oxygen limitation is supported by higher Y(L/G) in static culture. Modeling results show that the oxygen tension in the static culture is lower than that of the perfusion unit, where the cell density was 4 times higher. The experimental and modeling results show the dependence of cell metabolism and spatial growth patterns on the culture environment and highlight the need to optimize the culture parameters in hMSC tissue engineering.

Biological Transport↗
PubMedDate not supplied

Low-dosage adrenaline induces transient marked decrease of blood pressure during functional endoscopic sinus surgery.

BACKGROUND: Low-dosage adrenaline contained in local anesthetics is commonly used for hemostasis during functional endoscopic sinus surgery (FESS), but often causes significant hemodynamic side effects that might be neglected. A randomized, controlled, prospective clinical trial was designed to find out these effects after local infiltration of different concentrations and/or different dosages of adrenaline during FESS under general anesthesia. METHODS: One hundred eight adult patients were randomized into one of four groups to receive 2 mL of 2% lidocaine and adrenaline 1:200,000 (group I), 4 mL of 1% lidocaine and adrenaline 1:400,000 (group II), 4 mL of 1% lidocaine and adrenaline 1:200,000 (group III), or 4 mL of 1% lidocaine (group IV) for local infiltration, respectively. Heart rate, systolic blood pressure (BP), diastolic BP, and mean arterial pressure were monitored continuously in radial artery. RESULTS: Significant hemodynamic changes, particularly decrease of BP (p < 0.001) with slightly increased heart rate (p < 0.001) approximately 1.5 minutes after local infiltration, were observed in group I, group II, and group III compared with the baseline, but not in group IV. However, no significant hemodynamic changes were observed between group I, group II, and group III at the same time points (p > 0.05). CONCLUSIONS: Local infiltration of low-dosage adrenaline causes temporary significant hemodynamic changes, particularly marked decrease of BP during FESS, and there were no significant hemodynamic changes between adrenaline 1:200,000 and 1:400,000.

Adolescent↗