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Biomedical subjects

Y Feng

Publications and source records attributed to Y Feng.

At least 199 records · Page 11Linked to original sources
PubMed1999

[The expression of MTS1 gene product in transitional mucosa adjacent to rectal carcinomas and its clinical significance].

OBJECTIVE: To study the property of transitional mucosa (TM) adjacent to rectal carcinoma and the clinical significance of MTS1 gene deficit. METHODS: We used the immunohistochemical methods to observe the range of TM adjacent to rectal carcinoma, and the immunohistochemical method to observe the expression of MTS1 gene product on TM, using normal mucosa and carcinoma tissue as control. RESULTS: The positive expression level of MTS1 gene product was the highest in the normal rectal mucosa, gradually defective in TM and carcinoma tissue (P < 0.05). The range of TM with MTS1 negative cases was prominently larger than that with MTS1 positive cases (P < 0.05). CONCLUSIONS: The inactivation of MTS1 gene is relative to the occurrence of rectal carcinoma, suggesting that the TM adjacent to rectal carcinoma possess as certain potential malignancy. TM is related to MTS1 gene expression deficit of rectal carcinoma, showing that MTS1 gene expression deficit or mutation may be a factor inducing transitional change adjacent to carcinoma.

Adult↗
PubMed1999

[Effects of yi qi tong mai oral liquid on acute myocardial ischemia in dogs].

The objective of this study was to assess the prophylactic and therapeutic effects of Yi Qi Tong Mai Oral Liquid (YQTMOL) on acute myocardial ischemia. The models of ischemia were made, in which the anterior coronary arteries of anesthetized dogs were ligated. Four groups of dogs were examined and compared. We determined the extent of their myocardial ischemia and infarction by means of epicardial mapping and N-BT staining. The results showed that in the treatment groups, the increase of sigma-ST was inhibited 30-180 minutes after the oral administration of YQTMOL(compared with control group, P < 0.01), and the sigma-ST was decreased (P < 0.05). Furthermore, in the group dosed with YQTMOL (10 g/kg), the ratios of "area of infarction/heart weight" and "area of infarction/ventricle weight" both decreased (compared with control group, P < 0.05). These findings indicated that YQTMOL reduced the area of myocardial ischemia and the degree of myocardial infarction in dogs, so it could be effective for the prevention and treatment of acute myocardial ischemia.

Animals↗
PubMed1999

[Clinical usefulness of serum IFN-gamma level in patients with chronic obstructive pulmonary disease].

The objective of this study was to gain a clear idea of rule of change in serum IFN-gamma level in patients with chronic obstructive pulmonary disease and to evaluate the clinical usefulness of IFN-gamma as a marker of immune condition. The serum IFN-gamma levels of 15 patients with chronic bronchitis, 15 patients with cor pulmonale, 15 patients with acute bronchitis, and 15 normal subjects were measured by radio-immuno-assay. Differences between the four groups were tested, and in the chronic bronchitis group, the serum IFN-gamma levels, before and after treatment were compared. The results showed that compared with the normal group (0.8 +/- 0.17 IU/ml), the serum level changed little in the cor pulmonale group (0.93 +/- 0.25 IU/ml); it was not higher in the chronic bronchitis group (1.23 +/- 0.39 IU/ml, P > 0.05), but it went up significantly after treatment for 7 days (1.84 +/- 0.51 IU/ml, P < 0.05). The highest level of IFN-gamma was noted in the acute bronchitis group (2.24 +/- 0.71 IU/ml, P < 0.01). There was a significant difference compared with other groups (P < 0.01). These results suggest that relative deficiency of serum IFN-gamma may be a factor inducing repeated respiratory infection, and the serum level of IFN-gamma can be used as an index to assess the immune condition of patients with chronic obstructive pulmonary disease.

Biomarkers↗
PubMed1999

[Research on inhibition of areca nut extract on human buccal keratinocytes].

OBJECTIVE: To culture human oral mucosa epithelial cells in vitro and study the mechanism of changes in the epithelia of oral submucous fibrosis (OSF). METHODS: The keratinocytes were obtained from normal buccal mucosa (NM-KC) and OSF buccal mucosa (OSF-KC) with dispase trypsine and cultured in vitro. Then the cell proliferation of keratinocytes incubated with or without areca nut extract in the presence of 10% fetal calf serum for 48 hours at 37 degrees C in 5% CO2 and air were monitored by use of thiazolyl blue (MTT) assay. RESULTS: Primary culture grew in small islands that coalesced at confluency. Ultrastructurally the cells contained a large of tonofilament and microvilli. Immunohistochemistry demonstrated uniform staining of the cells with antibodies to keratins. There was no difference in cell proliferation between OSF-KC and NM-KC, and areca nut extract inhibited keratinocyte proliferation in a concentration-dependent manner. CONCLUSION: The results suggested that utilizing dispase II can establish fibroblast-free culture for growing of human oral mucosa keratinocytes and areca nut extract is a cytotoxic agent to human buccal keratinocytes.

Areca↗
PubMed1999

[Evaluation of N staging of cervical lymph nodes with positive palpation in laryngeal carcinoma].

OBJECTIVE: To evaluate N staging of cervical lymph nodes with positive palpation objectively. METHOD: Serial sections of lymph nodes of neck dissections with transparent methods were observed under light microscope. RESULT: 81 lymph nodes with pathological metastases were verified in 100 patients with 114 palpation positive lymph nodes. The correspondent rate was 71.1%. The correspondent rate of clinical N via pathological N staging was N1 35.6%, N2a 25.0%, N2b 58.3%, N2c 75.0%, N3 100.0% respectively. CONCLUSION: N staging judged only by palpation is not sufficient in clinic. It should be combined with other examinations.

Carcinoma, Squamous Cell↗
PubMed1999

[Retention behavior of solutes on liquid chromatographic column packed with dynamically modified zirconia].

Zirconia was dynamically modified with stearic acid, beta-cyclodextrin and sodium dodecylsulfonate, separately, to form liquid chromatographic packings. The chromatographic behaviors of aromatic hydrocarbons, acidic compounds (phenol, nitrophenols and benzoic acids) and basic compounds (aniline, nitroanilines and toluidines) were investigated on these modified zirconia packings with a mixture of methanol/water as the mobile phase. On stearic acid modified zirconia, aromatic hydrocarbons and the basic compounds exhibit symmetrical peaks. The retention time of these solutes decreases with increasing the concentration of methanol in the mobile phase. When the mobile phases with stearic acid were used, the retention time of these solutes has a maximum with variation of stearic acid concentration (0-1.0 mmol/L) in the mobile phase. However, the acidic compounds such as nitrophenols and benzoic acids are strongly adsorbed and can not be eluted from the column with the mobile phases. No leaking of stearic acid on the modified zirconia was found after 3000 column volumes of the methanol/water mobile phase were used. The results showed that the stearic acid modified zirconia can be used as a stationary phase for reversed-phase liquid chromatography. On beta-cyclodextrin modified zirconia, aromatic hydrocarbons and basic compounds exhibit shorter retention time than those on the stearic acid modified zirconia under the same mobile phase composition, however, nitrophenols can be eluted but give unsymmetrical peaks. On sodium dodecylsulfonate modified zirconia packings, the basic compounds can not be retarded; Aromatic hydrocarbons and acidic compounds exhibit short retention time. The results can be ascribed to the weak adsorption of sodium dodecylsulfonate on the zirconia.

Adsorption↗
PubMed1999

[Study on high performance liquid chromatography/indirect photometric detection of fosfomycin with acridine as detection reagent].

Fosfomycin is a broad-spectrum antibacterial agent which has strong polarity and weak UV absorption. In this work, a method using standard ODS column and conventional UV detector set at 254 nm to analyse fosfomycin was investigated. Firstly, several UV detection reagents were tested and acridine(A) was found to give the highest indirect detection response and proper modification on retention of fosfomycin. With acridine as the UV detection reagent, the mobile phase parameters which affect retention and detection response of solute are discussed, e.g. pH, concentration of organic solvent and concentration of acridine. The mechanism is interpreted for each case. After optimization, we adopted mobile phase as V(CH3OH):V(H2O) = 50:50, pH 3.18, [HAc] = 2 mmol/L, [A] = 1 x 10(-5) mol/L. A new chromatographic system monitored by indirect photometry for detection of fosfomycin was established. This method was used for quantitative analysis, the minimum detectable level was 10 mumol/L, the relative deviation was 4.51%.

Acridines↗
PubMed1999

[Preparation of zirconia for high performance liquid chromatography using sol-gel technology].

Zirconia sol was prepared by dissolving zirconyl chloride in water, and the sol formed gel in water/cyclohexane W/O style emulsion to obtain monodispersed particles of ZrO2(2-10 microns). After being washed and classified, the zirconia particles (3-5 microns) were collected and calcined at 800 degrees C to remove the organic residues on the surface of the particles. The mean pore diameter, specific surface area and specific pore volume of the zirconia particles were found to be 14.2 nm, 11.2 m2/g, and 0.04 cm3/g, respectively, by means of the BET method. The adsorption behavior of various organic compounds on the ZrO2 shows it will be useful as a column packing material for high performance liquid chromatography.

Adsorption↗
PubMed1999

[Application of power band graph method to the modeling and simulation of cardiovascular system].

This paper presents a computer simulation model of the cardiovascular circulation system, which describes the blood flow dynamic law in the cardiovascular system by the state equation. The model can be used in physiological study and computer-aided medical education. In this paper, the Power Band Graph (PBG) modeling method is used to realize modeling of the human circulation system and conduct a simulation study on a simplified physiological system model. The results demonstrate that the PBG method, as an understandable and unity modeling method, is quite effective and practicable and can be used widely in the field of physiological system simulation.

Computer Simulation↗
PubMed1999

[GC-MS analysis of volatile oil of herba Pogostemonis collected from Gaoyao county].

The chemical constituents of the volatile oil of the stems and leaves of Pogostemon cablin collected from Gaoyao county, Guangdong province, have been studied by means of GC-MS. Sixty four compounds have been identified. The main constituents are pogostone (30.99% in stems, 21.31% in leaves, the same below), patchouli alcohol (10.26%, 37.53%), transcaryophyllene (4.92%, 6.75%), alpha-guaiene (2.27%, 6.18%) and seychellene (1.56%, 1.99%), etc.

China↗
PubMed1999

[The 1. 54 microm laser and upconversion luminescence of YELPP noncrystalline induced by 969 nm LD laser].

In this paper, the absorption of Er3+, Yb3+ penta-phosphate noncrystalline (YELPP) was measured and the basic spectral parameters were calculated. Adopting the longitudinal-pump method with a domestic diode laser (LD), we achieved CW 1.5 microm chipped laser in China for the first time. The power of 1.5 microm laser was quite stable. The target of 1.5 microm laser reached the international level of early 1990s' in this field. In addition, the up-conversion luminescence was measured under the condition that 1.5 microm laser was either oscillating or not. The relationship between 1.5 microm chipped laser and up-conversion luminescence was analyzed initially.

English Abstract↗
PubMed1999

[Direct upconversion sensitization luminescence of Tm(0.1) Yb (10.9) oxyfluoride vitroceramincs].

This paper studied the direct upconversion sensitization luminescence of Tm (0.1) Yb (10.9) oxyfluoride vitroceramics pumped by 966 nm diode laser for the first time. We found that there are both strong 477 nm three-photon upconversion fluorescence of 1G4 --> 3H6 transition and 799.5 nm two-photon upconversion fluorescence of 3H4 --> 3H6 transition as well as weak upconversion fluorescence of 1D2 --> 3H6, 1Dz --> 3F4,1G4 --> 3F4 and 3F3 --> 3H6 transitions at 361 nm, 449.5 nm, 647.0 nm and (679.5, 698.5 nm), respectively.

English Abstract↗
PubMed1999

VEGF-induced permeability increase is mediated by caveolae.

PURPOSE: To determine the cellular route by which vascular endothelial cell growth factor (VEGF) increases the permeability of cultured retinal endothelial cells and to test whether nitric oxide (NO) production by NO synthase (NOS) is involved in signaling VEGF's permeability enhancing effects. METHODS: Cultured bovine retinal microvascular endothelial (BRE) cells were used for bioassay of permeability function and its ultrastructural correlates. The role of NOS activity in VEGF's permeability enhancing effects was tested with the use of an NOS inhibitor. Because activity of endothelial NOS (eNOS) is thought to be regulated by its interaction with the caveolar protein caveolin-1, structural relationships between eNOS, caveolin-1, and the VEGF receptor FIk-1/KDR were analyzed with double-label immunofluorescence and cell fractionation procedures. RESULTS: Bioassays of permeability function and structure demonstrated that VEGF increases permeability of cultured BRE cells by an NOS-dependent process of transcytotic transport in caveolae. Double-label analysis showed that Flk-1/KDR and eNOS colocalize with caveolin-1 in plasma membrane caveolae. Cell fractionation and immunoblot analysis confirmed this effect. Densitometry showed that Flk-1/KDR, eNOS, and caveolin-1 levels were highest in caveolar fractions. Similar results were obtained in studies with bovine aortic endothelial cells. CONCLUSIONS: These results demonstrate that VEGF increases endothelial cell permeability by an eNOS-dependent mechanism of transcytosis in caveolae. Localization of Flk-1/KDR and eNOS with caveolin-1 suggests that VEGF signaling occurs within the caveolar compartment.

Actins↗
PubMed1998

The involvement of mnn4 and mnn6 mutations in mannosylphosphorylation of O-linked oligosaccharide in yeast Saccharomyces cerevisiae.

The structure of O-linked acidic oligosaccharide from Saccharomyces cerevisiae was analyzed. The chitinase, exclusively O-glycosylated extracelluar protein, was purified from strains mnn1, mnn1 mnn4, mnn1 mnn6 and deltakre2 and the oligosaccharides were hydrolyzed by O-linked sugar chain specific hydrazinolysis. The mannosylphosphorylated mannotriose (M3-P-M) was detected in strain mnn1, but not in the other three strains (mnn1n mnn4, mnn1 mnn6 and deltakre2). alpha-Mannosidase treatment and matrix-assisted laser desorption ionization time-of-flight mass spectrometry of mannosylphosphorylated mannotriose revealed that mannosylphosphate was attached to a middle mannose of alpha-1,2-linked mannotriose. This result indicates that the mnn4 and mnn6 mutations affect the mannosylphosphorylation of O-linked oligosaccharide, together with that of N-linked oligosaccharide. The amount of mannosylphosphorylated mannotriose was 7% of total O-linked oligosaccharides (20% of neutral mannotriose) of chitinase in strain mnn1.

Alkaline Phosphatase↗