Biomedical subjects

Y Fan

Publications and source records attributed to Y Fan.

At least 37 records · Page 2Linked to original sources

PubMed2001

[Design and improvement of stenosis model in cylindrical tubal flow via pulsed Doppler ultrasound in vitro].

A model of disturbed flow downstream of a severe stenosis has been established and improved in vitro, and the relevant method and feasibility for the detection of flow indices are discussed via commercially available Pulsed Doppler Ultrasound (PDU). Detection is done temporally and spatially, upstream and downstream. The methodology is proved to be feasible and has good prosperity of clinical use.

Constriction, Pathologic↗

PubMed2001

[3D visualization and information interaction in biomedical applications].

3D visualization and virtual reality are important trend in the development of modern science and technology, and as well in the studies on biomedical engineering. This paper presents a computer procedure developed for 3D visualization in biomedical applications. The biomedical models are constructed in slice sequences based on polygon cells and information interaction is realized on the basis of OpenGL selection mode in particular consideration of the specialties in this field such as irregularity in geometry and complexity in material etc. The software developed has functions of 3D model construction and visualization, real-time modeling transformation, information interaction and so on. It could serve as useful platform for 3D visualization in biomedical engineering research.

Biomedical Engineering↗

PubMed2001

[Studies on association between lipoprotein lipase gene polymorphisms of Pvu II site and hypertriglyceridemics in Chinese].

OBJECTIVE: To explore whether Pvu II restriction fragment length polymorphisms (RFLP) in the lipoprotein lipase(LPL) gene are associated with hypertriglyceridemics (HTG). METHODS: Pvu II restriction fragment length polymorphisms in the lipoprotein lipase gene on a sample of 135 HTG patients and 193 age-matched healthy individuals in Chengdu area were detected with the method of PCR-RFLP. RESULTS: The P+ P+ genotype frequency and P+ allelic frequency of LPL gene for HTG cases are higher than those for control groups (0.460 vs 0.337,P<0.05; 0.689 vs 0.565,P<0.01). The serum levels of TGapoCII, apoCIII, apoE and TG/HDL-C in P+P+ genotype are higher than those in P-P- genotype(P<0.05). CONCLUSION: The results suggest that P+P+ genotype in the lipoprotein lipase gene is associated with susceptibility to hypertriglyceridemics in Chinese population.

Adult↗

PubMed2001

[Experiment of biodegradation of chlorobenzenes].

Four strains of microorganisms which were able to grow at the presence of 1,4-dichlorobenzene 1,2,4-trichlorobenzene and hexachlorobenzene were isolated from the sludge collected from two different sites after incubating about 2 months. During the growth of the mixed microorganisims on chlorobenzenes, the accumulating consumption of oxygen, the microbial population curve and the concentration of released Cl- were investigated. The result showed that the mixed microorganisms were able to utilize 1,4-dichlorobenzen and 1,2,4-trichlorobenzene as sole carbon source and energy source. The concentration of released Cl- may depend strongly on the activity of the living cells. The order in which the chlorobenzenes were readily degraded was 1,4-dichlorobenzenez[356.7 micrograms/(L.d)] > 1,2,4-trichlorobenzene[110.4 micrograms/(L.d)] > hexachlorobenzene[approximately 6 micrograms/(L.d)]. The number of the substituted chlorine on the chlorobenzenes directly resulted in the resistance to biodegradation.

Bacteria↗

PubMed2001

[The influence of ecological factors on simultaneous nitrification and denitrification in MBR].

The influence of dissolved oxygen(DO), C/N and pH on simultaneous nitrification and denitrification in the membrane bioreactor was studied. The experimental results showed that only under condition that each ecological factor was maintained relative steady, simultaneous nitrification and denitrification might proceed smoothly. When DO, C/N and pH of feed water was 1 mg/L, 30 and 7.2, the removal rate of COD, NH4+, and TN were 96%, 95% and 92% respectively.

Bioreactors↗

PubMed2001

[Treatment of dying wastewater from a woolen mill with a pilot-scale anaerobic/oxic membrane bioreactor (A/O MBR)].

A pilot-scale (10 t/d) anaerobic/oxic membrane bioreactor (A/O MBR) was used for treatment of dying wastewater from a woolen mill. The results showed that when COD, BOD5 and color in the influent was 179-358 mg/L, 44.8-206 mg/L and 50-240 dilution times (DT), the average COD, BOD5 and color of A/O MBR effluent was 20.2 mg/L, 1.6 mg/L, 25 DT respectively. The removal of COD, BOD5, color, turbidity was 92.1%, 98.4%, 60.7% and 98.9% respectively. Each quota of the treated water met the gray water standards (CJ25.1-89). The A/O MBR process has many advantages, such as stable performance, simple operation, easy management etc. The result of this work could be reference for the designing of industrial scale A/O MBR process for treatment of the woolen mill wastewater.

Anaerobiosis↗

PubMed2001

[The application of air-lift loop column filling with porous carrier in wastewater treatment].

An air lift loop reactor filling with porous carrier particles was utilized as aeration column. Experiments were carried out in wide operating conditions. The experimental results showed that in the range of gas flow rate from 0.117 to 0.156 m3/(min.m3), a higher efficiency of removal of ammonium-N was achieved, and when the gas flow rate was above 0.039 m3/(min.m3), the COD was completely degraded in about 1 h. The filling ratio of the porous carriers in the column was an important factor for the removal of C and N compounds, and a filling ratio of 15% was proved to be most suitable in the operation ranges. The experimental results also indicated that the effect of aeration temperature on the removal efficiency was significant and the highest efficiency was obtained at around 25 degrees C.

Nitrogen↗

PubMed2001

[Preliminary study of effect of antisense hsc70 effect on the stability of mutant p53 protein].

OBJECTIVE: To investigate the effect of antisense hsc70 RNA on the stability of mutant p53 protein. METHODS: Using DNA recombination technique, retroviral recombinant expressing antisense hsc70 RNA was constructed and transfected into MCF7/Adr cells. After the existence of foreign DNA had been identified by the polymerase chain reaction (PCR) method, the protein level of hsc70 was detected by Western blot. The half-life of mutant p53 was detected by p53 stability assay. RESULTS: With the stable expressive transfectant cell strains obtained through G418 selection, the foreign DNA in transfectant cells were confirmed by PCR method and the repression rate of hsc70 protein was 42%. The half-life of mutant p53 in MAc70 cell was 10 hours which was significantly lower than the control cells. CONCLUSION: Antisense hsc70 RNA is able to lower the hsc70 protein level and significantly increase the instability of mutant p53 protein in MCF7/Adr human breast cancer cells.

Blotting, Western↗

PubMed2001

[Preparation of green fluorescent protein retrovirus and its application in mediating gene transfer into retinal pigment epithelial cells].

OBJECTIVE: To determine whether human retinal pigment epithelial (RPE) cells can be infected by retrovirus and modified by retrovirus-mediated gene transfer. METHODS: Recombination retroviral vector pLNCX-GFP (green fluorescent protein, GFP) was generated by inserting 780 bp GFP cDNA fragment into the MCS site of pLNCX. pLNCX-GFP was transfected into ecotropic packaging cell line PhiX-Eco and amphotropic packaging cell line PhiX-Ampho and PA317. Retroviral titer was tested by counting GFP expression of NIH3T3 cells. Then RPE cells were infected by using GFP retrovirus-containing supernatant. RESULTS: GFP was expressed and retrovirus was produced upon pLNCX-GFP being transfected into packaging cell line. The GFP retrovirus was able to infect primary cultured human RPE cells and immortalized RPE cell line. CONCLUSION: The retrovirus can introduce a foreign gene into RPE cells efficiently, thereby it can be used as an important tool to deliver gene into RPE for therapy of fundus diseases.

Cells, Cultured↗

PubMed2001

[Association between renin activity, angiotensin II and ovarian hyperstimulation syndrome].

OBJECTIVE: To investigate the association between renin-like activity (RA) and angiotensin II (A II) and the ovarian hyperstimulation syndrome (OHSS). METHODS: Blood samples were taken from 42 patients undergoing in vitro fertilization (IVF). According to the ovarian stimulating response, the patients were divided into 4 groups: group I, low responders, 7 cases; group II, moderate responders, 8 cases; group III a high responders without using albumin, 7 cases, group III b, high responders with albumin, 10 cases; group IV, severe and moderate OHSS, 10 cases. 5 patients for intrauterin insemination with natural cycle as control. Follicular fluid (FF) was collected at oocyte retrieval from 28 IVF patients (including 7 OHSS patients). Fluid from ascites and hydrothorax was obtained from 3 OHSS patients, and peritoneal fluid obtained from 5 infertility patients by laparoscopy and ascitic fluid obtained from 6 ovarian carcinoma patients served as control. RA and A II levels were measured by radioimmunoassay. RESULTS: Plasma RA and A II levels at mid-luteal phase from OHSS patients [(19.9 +/- 19.0) micrograms.L-1.h-1 and (397.0 +/- 378.2) ng/L] were significantly higher than those from the other patients (P < 0.01-0.05), also the levels at mid-luteal phase from IVF patients were significantly higher than those at late-follicular phase [(4.1 +/- 2.9)-(4.9 +/- 3.2) micrograms.L-1.h-1 Vs (1.5 +/- 0.9)-(1.9 +/- 1.0) micrograms.L-1.h-1, (85.5 +/- 49.5)-(109.4 +/- 46.0) ng/L Vs (33.6 +/- 15.9)-(37.0 +/- 17.1) ng/L, P < 0.01-0.05]. RA and A II levels in FF were significant higher than those in plasma (P < 0.01-0.05). A II in ascitic fluid in OHSS patients was 4 to 8 times higher than that in plasma, while RA in ascitic fluid was 1.5 to 3 times higher than that in plasma, but the levels of A II and RA in controls were very low. The plasma RA and A II levels dropped very significantly along with clinical improvement (P < 0.01). CONCLUSION: These findings suggest that RA and A II are associated with the pathogenesis of capillary leakage in OHSS.

Angiotensin II↗

PubMed2001

[The influences upon the passive tensile of the masticatory muscles and ligaments by Herbst appliance under various bite reconstruction--a three dimensional finite element analysis].

OBJECTIVE: This study aimed to provide some biomechanical references for the clinical use and improvement of Herbst appliance. METHODS: The three-dimensional model of the 'Temporomandibular joint mandible Herbst appliance system' was set up by SUPER SAP software (version 9.3). On this model, the passive tensile in the masticatory muscles and ligaments were analyzed under various bit reconstruction designed according to specified advanced displacement and vertical bite opening. RESULTS: When Herbst appliance drove the mandible forward, there was not any tensile in the medial, lateral pterygoid and the collateral ligament, while the temporalis, the deep paret of masseter, the stylomandibular ligament, and the sphenomandibular ligament were passively drawn. Under various bite reconstruction, the passive tensile in the medial temporalis, the posterior temporalis, the stylomandibular ligament and the sphenomandibular ligament increased with the amount of the advancement of the mandible; The passive tensile in the posterior temporalis and the deep part of masseter increased with the amount of vertical bite opening of the mandible. CONCLUSION: The StL, SpL, PT and AT played an important role in functional reconstruction of mandible by Herbst. All five group of bite reconstruction (3-7 mm advancement, 4-2 mm vertical bite opening of the mandible) designed by this study can be selected in clinic according to the patient's capability of adaptation, the extent of malocclusion and the potential and direction of growth.

Finite Element Analysis↗

PubMed2001

[The influences of the stress distribution on the condylar cartilage surface by Herbst appliance under various bite reconstruction--a three dimensional finite element analysis].

OBJECTIVE: The distribution of stress on the surface of condylar cartilage was investigated. METHODS: Three-dimensional model of the 'Temporomandibular joint mandible Herbst appliance system' was set up by SUPER SAP software (version 9.3). On this model, various bite reconstruction was simulated according to specified advanced displacement and vertical bite opening. The distribution of maximum and minimum principal stress on the surface of condylar cartilage were computerized and analyzed. RESULTS: When Herbst appliance drove the mandible forward, the anterior condyle surface was compressed while the posterior surface was drawn. The trend of stress on the same point on the condyle surface was consistent in various reconstruction conditions, but the trend of stress on various point were different in same reconstruction conditions. CONCLUSION: All five groups of bite reconstruction (3-7 mm advancement, 4-2 mm vertical bite opening of the mandible) designed by this study can be selected in clinic according to the patient's capability of adaptation, the extent of malocclusion and the potential and direction of growth.

Cartilage, Articular↗

PubMed2001

[Clinical application of three-dimensional spiral CT in the complex maxillofacial fractures].

OBJECTIVE: The aim of this study was to evaluate the clinical application of the three-dimensional spiral CT in the complex maxillofacial fractures. METHODS: A total of 26 patients with complex maxillofacial fractures were examined using spiral CT with the slice thickness of 3 to 5 mm. The surface shaded display (SSD) method was used for reconstruction of the three-dimensional (3D) images. The three-dimensional images of maxillofacial fractures were obtained by using various rotations. Before the three-dimensional images were reconstructed, the drawing and deleting way was used for these mandibular fractures. RESULTS: The method demonstrated clearly the three-dimensional anatomy and their relationships of the fractures; using the drawing and deleting way, location and move condition of mandibular fractures, especially condylar fractures, were showed clearly. CONCLUSION: The three-dimensional CT is important in evaluating complex maxillofacial fractures. It could be used to demonstrate clearly locations and move conditions of complex maxillofacial fractures and operative plans.

Adolescent↗

PubMed2001

[Advances in solid phase microextraction coupled with high performance liquid chromatography].

Solid phase microextraction (SPME) is a solvent-free technique with high extraction efficiency and easy to perform automatically. It can be coupled with high performance liquid chromatography to perform efficient analysis of compounds with high polarity. The advances in solid phase microextraction coupled with high performance liquid chromatography, including its theory, interfaces, coating materials and applications, are reviewed with 36 references.

Chromatography, Gas↗

PubMed2001

[Influence of clinical staging of type III sinusitis on the operative effectiveness].

OBJECTIVE: To explore the influences of different degree of pathological changes in chronic polypous sinusitis patients on the effectiveness of endoscopic sinus surgery. METHOD: According to history, anatomic structures and severity of lesions, 104 cases (208 sides) of Type III sinusitis were divided into 3 stages. Rates of clinical effectiveness and complications were compared and analyzed. RESULTS: The total effective rates were 93.06%, 82.89% and 70.00% and the rates of complications were 5.56%, 14.47% and 25.00% in stages 1, 2, 3 respectively. CONCLUSION: The effective rates, difficulties and risks of operation depend upon the anatomic variations (integration of ostiomeatal complex) and the degree of lesions (augmentation of granulation and osseous hypertrophy of ethmoid bone). All these should be listed as objective bases in classifying stages of patients which will play a directional role in clinical work.

Adolescent↗

PubMed2000

Improving the performance of MALDI-TOF in oligonucleotide analysis using a new SDIFA technology.

A new technology termed SDIFA is developed to improve the mass resolution of linear matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in oligonucleotide analysis. Unlike the currently used delayed extraction method, SDIFA allows electrical isolation of the sample holder from ion extraction/acceleration and selectively samples part of the desorbed ions, thereby reducing the initial velocity distribution and improving resolution. In addition, a method was introduced to improve the space focusing of TOF. Isotope-limited mass resolution was obtained for oligonucleotides of up to 62 mer, and the true instrumental resolution reaches to 1,800 at 19.2 kDa. It was also demonstrated that excellent resolution was obtained across a large mass range using a single setting of acquisition parameters. This feature allows unambiguous identification of multiple A/T heterozygote samples in a mass range of 5,200-7,800 Da. Moreover, compared with DE, the performance of SDIFA was more stable, reproducible, and less dependent on the experimental conditions including the laser power, sample spots, sample substrates, delayed time, and extraction field strength. This enhanced ease of data acquisition is the key to automated spectrum acquisition.

Oligonucleotides↗

PubMed2000

Effect of diet on colonic-programmed cell death: molecular mechanism of action.

Colon cancer evolves from a progressive inhibition of apoptosis and is influenced strongly by diet. Among dietary factors, butyrate (derived from fermentable fibers) may have utility as a chemopreventive agent because of its ability to promote apoptosis. Because CD95 (APO-1/Fas) transduces signals resulting in apoptosis, we tested the hypothesis that butyrate-dependent colonocyte apoptosis is mediated by this death receptor. Treatment of immortalized mouse colon cells with Fas agonistic antibody induced cell death, indicating that Fas in colonocytes is functional. Antagonism of Fas signaling using a soluble Fas:Fc chimera blocked butyrate induction of apoptosis. Therefore, Fas receptor dependent signal transduction is required for butyrate induction of apoptosis in colonic cells.

Animals↗

PubMed2000

Characterization of the U(L)33 gene product of herpes simplex virus 1.

The U(L)33 protein is one of six genes (including U(L)6, U(L)15, U(L)17, U(L)28, and U(L)32) required for cleavage of viral concatemeric DNA into unit-length genomes and packaging of the virus genomes into preformed capsids. The U(L)25 gene product is dispensable for cleavage of viral DNA but essential for packaging of DNA into capsids. A polyclonal antiserum was produced against an affinity-purified protein containing the full-length U(L)33 gene product of herpes simplex virus 1 fused to glutathione-S-transferase. A protein of approximate M(r) 19,000 that reacted with the antiserum was detected in immunoblots of herpes simplex virus 1-infected cellular lysates. This protein was not detected in lysates of mock-infected cells or cells infected with a mutant virus containing a stop codon in U(L)33, indicating that the 19,000 M(r) protein is the product of the U(L)33 open reading frame. The U(L)33 gene product was not detected in purified virions or capsids. Accumulation of the U(L)33 protein to detectable levels required viral DNA synthesis, indicating that the protein was regulated as a late gene. Indirect immunofluorescence analysis demonstrated that U(L)33 protein accumulated predominantly within replication compartments in the central domains of infected cell nuclei and within the cytoplasm. Localization of the U(L)33 gene product in replication compartments was maintained in cells infected with a variety of cleavage/packaging mutants.

Animals↗