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Biomedical subjects

Y Shi

Publications and source records attributed to Y Shi.

At least 325 records · Page 18Linked to original sources
PubMed1999

[Evidence of increased endogenous carbon monoxide production in asthma].

OBJECTIVE: To investigate the role of carbon monoxide (CO) in the pathogenesis of asthma. METHODS: We examined CO, nitrite and nitrate (NO2[not readable: see text]/NO3[not readable: see text]) and tumor necrosis factor alpha (TNF-alpha) levels in plasma of 26 asthmatic children and 22 matched normal children. At the same time, we examined the plasma and bronchoalveolar lavage fluid (BALF) CO, NO2[not readable: see text]/NO3[not readable: see text] and TNF-alpha levels in guinea-pigs with allergic asthma. RESULTS: Asthmatic children in acute attack stage had increased levels of CO, NO2[not readable: see text]/NO3[not readable: see text] and TNF-alpha in plasma compared with normal control subjects (all P < 0.01), while in stable stage plasma CO and NO2[not readable: see text]/NO3[not readable: see text] reduced to normal levels (both of the P > 0.05), but TNF-alpha was still higher than the normal controls (P < 0.01). Guinea-pigs with allergic asthma had increased amounts of CO and TNF-alpha in plasma and CO, NO2[not readable: see text]/NO3[not readable: see text] and TNF-alpha in BALF as compared with normal control subjects (P < 0.05-0.01), but no changes in levels of circulating NO2[not readable: see text]/NO3[not readable: see text] (P > 0.05) were found. There was no difference between glucocorticoid treated asthmatic guinea pigs and normal controls in levels of CO, NO2[not readable: see text]/NO3[not readable: see text], and TNF-alpha. The elevation of plasma CO correlated with elevated NO2[not readable: see text]/NO3[not readable: see text] level in asthmatic children (P < 0.05), so did in the BALF in allergic guinea-pigs. CONCLUSIONS: Our present data showed that endogenously produced CO was increased during the course of asthma, which suggested that the role of CO in asthma might worth further study.

Animals↗
PubMed1999

[Direct intramuscular injection of pSV-VEGF(165) augments capillaries formation in a rabbit model of hindlimb ischemia].

OBJECTIVE: To investigate an easier and safer clinical method of gene therapy for treating arterial ischemic diseases in the lower extremity. METHODS: Recombinant plasmid pSV-VEGF(165) constructed in vitro was directly injected into the ischemic hindlimb muscles in rabbit models. 30 days after gene transfer, the capillary density and the capillary to muscle fiber ratio were determined histochemically in the resected samples. RESULTS: The capillary density and the capillary to muscle fiber ratio were significantly higher for pSV-VEGF(165) transfected group than for control group, particularly increased in the shank of the hindlimbs. CONCLUSIONS: Direct intramuscular injection of pSV-VEGF(165) was an easier and efficient gene therapy method, and it significantly augmented the capillary formation in ischemic limbs.

Animals↗
PubMed1999

[The application of chopping method for phacoemulsification of hard nucleus cataract].

OBJECTIVE: The study was designed to investigate the application of chopping method for phacoemulsification of hard nucleus cataract. METHODS: Modified stop and chop technique was used to emulsify the hard nucleus cataract. The degree of nuclear hardness in 80 eyes was grade IV. RESULTS: Postoperatively, the visual acuity with correction was >or= 0.9 in 76.25% at 3 months. There were mild corneal edema in 8 cases, moderate corneal edema in 2 cases and posterior capsular rupture in 1 case. CONCLUSION: The modified stop and chop technique enables the tenacious nuclear plate to rupture easily, thus the stress on the zonules and capsule can be decreased, and in the mean time the technique needs less phaco energy and time.

Aged↗
PubMed1999

[TNF-alpha, IL-8 and IL-6 in the early inflammatory stage of experimental PVR model induced by macrophages].

OBJECTIVE: To observe the levels of cytokines, tumor necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8) and IL-6 in the early inflammatory stages of a rabbit proliferative vitreoretinopathy (PVR) model induced by macrophages. METHODS: The vitreous and venous blood of rabbit eyes of the PVR model were obtained and tested with ELISA kits of TNF-alpha, IL-8 and IL-6 and analyzed statistically. RESULTS: The TNF-alpha level increased at the 7th day after macrophage injection and reached its peak (309 pg/ml) on day 21. IL-8 and IL-6 maintained their higher levels during 7 to 21 days after macrophage injection and the peak levels were 1 325 pg/ml and 998 pg/ml on day 14 respectively. Those showed significant differences compared to control (P <or= 0.05). CONCLUSION: The 3 cytokines, TNF-alpha, IL-8 and IL-6, present high levels in the early stage and proliferative phase of the PVR model and decrease to normal level in the regeneration (scarring) phase, indicating that these cytokines may play an important role in initiating and modulating the cellular proliferation.

Animals↗
PubMed1999

[Study on the radioligand binding assay of cholecystokinin receptor in rat cerebral cortex].

A radioligand binding assay system for determining the characterization of CCK receptor is presented. Using Bolton-Hunter reagent, we prepared a biologically active, specific 125I-BH-CCK8. The iodination mixture was then transferred to a column of Sephadex G-25 and examined by silica thin layer chromatography. Its specific activity and radiochemical purity were 3.4 TBq/mmol and 96% respectively. Binding of 125I-BH-CCK8 to the membrane of rat cerebral cortex was rapid, reversible, time-temperature dependent, saturable and specific. The labeled CCK was shown to have biological activity as measured by the CCK receptor radioassay. Under our laboratorial conditions, the CCK binding required an hour to reach equilibrium at 4 degrees C. We chose polyethylene glycol 6,000 and gamma-globulin protein for the separation of B and F. Scatchard plot of CCK binding was linear with a Kd value of 1.098 nmol/L and Bmax of 197.5 fmol/mg protein. The results of this study support the stand-point that CCK may function as a regulatory peptide in brain and hence may be of use for clarifying the CCK receptor's function in central nervous system.

Animals↗
PubMed1999

[Left ventricular function evaluation after mitral valve replacement with preservation the subvalvular apparatus].

The objective of this study was to evaluate the left ventricular function after mitral valve replacement (MVR) with preservation of all chordae. Fourteen patients with a diagnosis of mitral regurgitation were studied. These patients, 4 males and 10 females, age from 24 to 59 years, who underwent mitral valve replacement, in which all chordae tendineae were preserved. The mean follow-up interval was 6 months. Preoperation and postoperation multigated equilibrium radionuclide angiography was performed by Elscint Helix Apex SPECT. Each patient was injected with 740MBq 99mTc-HSA, rest ejection fraction (global EF) of LV (%), regional ejection fraction (EF) of LV (%), PER/S and PFR/S were measured. Regional EF was calculated by the method of dividing the left ventricle into five segments by radial axis. The results showed that the postoperative EF of the whole left ventricle of the chordae-preserved patients was significantly greater than their preoperative EF (40.0% +/- 17.8%, to 51.6% +/- 18.2%, P < 0.02), and also the regional EF at the lateral wall of the chordae-preserved MVR was significantly greater than the preoperative regional EF (an increase from 51.0% +/- 18.1% to 69.7% +/- 21.2%, P < 0.01). MVR with preservation of all chordae, the patient's left ventricular function remarkably improved.

Adult↗
PubMed1999

[Methodological study of measuring flow field uniformity downstream of mitral valve using Doppler echocardiography].

The objective of this study was to establish a quantitative measurement of flow field uniformity of mitral valve in vivo. The flow field uniformity downstream of mitral valve in normal persons and patients with mitral stenosis were studied using advanced color Doppler flow imaging technique. The results showed that a significant difference was found in the quantitative items of flow field uniformity between normal persons and patients with mitral stenosis (P < 0.05). There was significant correlativity between the items of flow field uniformity and other routine items of Doppler echocardiography. The authors conclude that the method is safe, non-invasive, accurate and repeatable, and it can really reflect the flow field uniformity of normal persons and patients with mitral stenosis.

Adult↗
PubMed1999

[Autodetection of cell adhesion by light transmission].

To set up a new effective method for measuring the adhesion between red blood cells and vascular endothelial cells, we studied the relationship between adhesive red blood cells and light transmission by using Microscope-Photometric-Monolayer-Technique Elias-c Analyzer in our department. The results showed that the method of light transmission measurement on the adhesion between red blood cells and vascular endothelial cells is simple, effective and reliable.

Cell Adhesion↗
PubMed1999

[Differentiation of cultural endothelial cells].

The disparity of function and ultrastructural characteristics between cells in vivo and cultural cells in vitro has been attributed to the differentiation of cells, so differentiation is the key to detecting the differences between endothelial cells (ECs). The ECs are widely distributed over the entire inner surface of blood vessels in the body and exhibit noticeable heterogeneity. The cultural ECs also show heterogeneity. This is a literature review focusing on the recent advance in researches on the embryonic origin of ECs, the heterogeneity of ECs and the factors that influence differentiation of ECs. Also described is the prospect of studies aimed at elucidating the molecular mechanisms involved in the differentiation of ECs. It is hoped that future studies will enhance the realization of oriented differentiation of ECs.

Cell Differentiation↗
PubMed1999

[Study of bacterial adhesion to prosthetic valve materials in vitro].

This article reports a study of the bacterial adhesion to prosthetic valve materials in vitro. The method for assessing the degree of bacterial adhesion to prosthetic valve materials was established primarily. The capacities of staphylococcus aureus(SA), staphylococcus epidermidis(SE), Escherichia Coli(EC) and Pseudomonas aeruginosa(PA) for adhesion to Dacron, Pyrolytic carbon and polytetrofluoroethylene (PTFE) were quantitatively determined by the plate counting and Gamma-ray counting of 125I radiolabeled bacteria in vitro. The results showed that the capacities of four types of bacteria for adhesion to Dacron, Pyrolytic carbon and PTFE coincided with the bacterial-growth curve. The capacities of four bacteria for adhering to Dacron were stronger. The adhesion of SE to Pyrolytic carbon was the strongest. The adhesion of PA Kept up a high level. The capacities of EC and PA for adhering to PTFE were the strongest. The results indicate that the capacities of different types of bacteria for adhesion to the same prosthetic valve material are different, and the capacities of one type of bacteria for adhesion to different materials are also different.

Bacterial Adhesion↗
PubMed1999

[Study of cytotoxicity of bioprosthetic heart valve material and its store solution].

This study compared the cytotoxicities of bioprosthetic heart valve materials crosslinked by glutaraldehyde, stored in 4% formaldehyde or Hank's solution. Human embryonic pulmonary fibroblasts or L-929 cell culture in vitro were used. Cell proliferative inhibition index(CP II) was calculated for bioprosthetic heart valve materials using different store methods in different rinse periods(before, 10 days, 20 days, 30 days). The results demonstrate: (1) bioprosthetic heart valve materials stored in 4% formaldehyde or in Hank's solution both have significant cytotoxicity, and the longer the rinse time continues, the lower the cytotoxicity declines; (2) HEL cell is more sensitive than L-929 cell in detecting the cytotoxicity of toxic biomaterials but for weak toxic biomaterials the two cell lines are not significanth different; (3) formatldehyde solution increases the cytotoxicity of biomaterials stored in it, but the enhanced cytotoxicity can be easily relieved by rinse. The authors conclude that bioprosthetic heart valve materials have long term significant cytotoxicity and the biomaterial cytotoxicity test using human fibroblasts is more sensitive and precise than other tests.

Animals↗
PubMed1999

[The research of evaluation the compatibility of biotic material in cell-culturing method].

It is quick convienent good-repeating and cheap that examining the biotic material's compatibility through cell-culturing method, and it is more and more important in evaluating the compatibility of biotic material. The new material appearing continously complicating of the part and aim material be planted in the intensity of material's toxic effect the reaction's complication of material and biotic body, all of these decide the variety of experiment method and cells in cell toxicity experiment. It is very important that choices the right experiment method and cells according to the material's character the part and aim the material be planted in. The evaluation of biotic material's compatibility stressed on the changing of cell's form and quantity before. In recent years, more and more reports appear about material influences the growth. Adhesion proliferation and metabolizing of cell, and presents the point that the evaluation standard of biotic material's compatibility should be set according to the active cell's quantity and their growth. Combining many subject's technological development, such as immunology, chemistry, radiation and shadowgraphy, thoroughly inquires the changing relation of cell's structure and function, furtherly clarifes the material's effect on cell. It is the developing direction in the future that evaluates the biotic material's compatibility in cell-culturing method.

Cell Culture Techniques↗
PubMed1999

[Taxonomy of the producing strain of agricultural antibiotic 2-16].

In screening process of new agricultural, a streptomycetes, 2-16, was isolated from the soil sample collected in Huangsan. The secondary metabolites produced by the strain had strong inhibition to Sclerotinia sclerotiorum. By identification, this strain was regarded as new variety of Streptomyces ahygroscopicus and was called Streptomyces ahygroscopicus var. huangsanensis.

Agrochemicals↗
PubMed1999

[The isolation of microbe producing biosurfactants].

Microorganisms capable of producing biosurfactants can be isolated by a series of steps including hydrocarbon enrichment culture, hemolytic activity assay on blood agar plates and oil displacement activity assay etc. Ten strains(including bacteria, yeasts and fungi) were isolated with higher surface activity from 1000 samples from soil, sludge, waste water etc. Two strains of bacteria produced rhamnolipids and trehaloselipids respectively. One strain of bacterium produced long chain unsaturated carboxylic acid and another produced azelaic acid. Two strains of yeasts produced lipopolysaccharides with excellent emulsification property.

Bacteria↗
PubMed1999

[Observation on the effect of Sj32DNA vaccine of Schistosoma japonicum].

AIM: To explore the protective immunity against cercariae challenge in mice immunized with Sj32DNA vaccine of Schistosoma japonicum. METHODS: Primers were designed and the full length and part cDNA encoding 32 kDa(Sj32) amplified from pSj32 by PCR were cloned into pBK-CMV. Eukaryotic expression vector pBK-Sj32-1 containing full-length Sj32 cDNA and pBK-Sj32-2 containing fragment of Sj32 cDNA were constructed. After selection and identification, two plasmids were transfected into NIH 3T3 cells. The expression of Sj32 in transfected cells was confirmed by IFA. After identification, the two plasmids were prepared and purified on batches. Each BALB/c mouse was vaccinated at weeks 0, 3, and 5, by injection with 100 micrograms of purified Sj32DNA into quadriceps muscle. Mice immunized with constructs and the control mice were challenged four weeks after final DNA injection, and worms and the number of eggs in the liver tissue were counted at 8 weeks after challenge. RESULTS: Perfusion and egg counts showed significant differences in terms of worm reduction rate 38.6%-30.9% and egg reduction rate 55.7%-55.2% between the vaccinated and control mice. CONCLUSION: Sj32 DNA vaccine could result in protection against a subsequent challenge of S. japonicum in mice.

3T3 Cells↗