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Biomedical subjects

Hong Yan

Publications and source records attributed to Hong Yan.

At least 91 records · Page 5Linked to original sources
PubMed2003

Characteristics and application of established luciferase hepatoma cell line that responds to dioxin-like chemicals.

AIM: To establish a luciferase reporter cell line that responds dioxin-like chemicals (DLCs) and on this basis to evaluate its characteristics and application in the determination of DLCs. METHODS: A recombinant luciferase reporter plasmid was constructed by inserting dioxin-responsive element (DREs) and MMTV promoter segments into the pGL(3)-promoter plasmid immediately upstream of the luciferase gene, which was structurally demonstrated by fragment mapping analysis in gel electrophoresis and transfected into the human hepatoma cell line HepG(2), both transiently and stably, to identify the inducible expression of luciferase by 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD). The time course, responsive period, sensitivity, structure-inducibility and dose-effect relationships of inducible luciferase expression to DLCs was dynamically observed in HepG(2) cells stably transfected by the recombinant vector (HepG(2)-Luc) and compared with that assayed by ethoxyresorufin-O-deethylase (EROD) in non-transfected HepG(2) cells (HepG(2)-wt). RESULTS: The inducible luciferase expression of HepG(2)-Luc cells was noted in a time-, dose-, and AhR-dependent manner, which peaked at 4 h and then decreased to a stable level at 14 h after TCDD treatment. The responsiveness of HepG(2)-Luc cells to TCDD induction was decreased with culture time and became undetectable at 10th month of HepG(2)-Luc cell formation. The fact that luciferase activity induced by 3, 3', 4, 4'-PCB in HepG(2)-Luc cells was much less than that induced by TCDD suggests a structure-inducibility relationship existing among DLCs. Within the concentrations from 3.5 x 10(-12) to 5 x 10(-9) mol/L, significant correlations between TCDD doses and EROD activities were observed in both HepG(2)-luc and HepG(2)-wt cells. The correlation between TCDD doses from 1.1 x 10(-13) to 1 x 10(-8) mol/L and luciferase activities was also found to be significant in HepG(2)-luc cells (r=0.997, P<0.001), but not in their HepG(2)-wt counterparts. For the comparison of the enzyme responsiveness between cell lines to TCDD, the luciferase sensitivity and reproducibility in HepG(2)-luc cells were both better than that of EROD in HepG(2)-wt cells, the former was at 1.1 x 10(-13) mol/L and 3.5 x 10(-12) mol/L, and the coefficients of variation (CV) of the latter was 15-30 % and 22-38 %, respectively. CONCLUSION: The luciferase expression of HepG(2)-luc cells established in the present study could sensitively respond to the DLCs stimulation and might be a prospective tool for the determination of DLCs.

Carcinoma, Hepatocellular↗
PubMed2003

[Effects of medium and long-chain triglyceride on the immune function of burn patients during early postburn stage].

OBJECTIVE: To explore the effects of medium and long-chain triglyceride on the immune function of burn patients during early postburn stage and its possible mechanism. METHODS: Thirty burn patients with TBSA exceeding 30% were enrolled in this study and were randomly divided into two groups (n = 15 in each group). The patients in F group were supplemented orally with enteral nutrient Fresubin 750MCT containing medium (MCT) and long-chain triglyceride (LCT), and those in N group with Nutrition containing only LCT. All the patients were treated with nutritional support beginning from 24 PBH, continued for 10 days. The changes in plasma levels of IL-2, IL-4, PGE(2) and T lymphocyte transformation rate (LTR) in peripheral blood of patients in the two groups were determined on 1, 4, 7 and 10 postburn days (PBDs). RESULTS: The plasma IL-2 level in all time points exhibited no difference in all patients (P > 0.05). The plasma level of PGE(2) on PBD 4 in F group was obviously lower than that in N group (P < 0.01). The plasma level of IL-4 on PBDs 4, 7 and 10 in F group were evidently higher than that in N group (P < 0.01). The T LTR in peripheral blood on PBDs 4 and 7 in F group was much higher than that in N group (P < 0.05 - 0.01). CONCLUSION: Enteral nutrient containing MCT/LCT seemed to be superior to that containing only LCT in the improvement of postburn immune function in burn patients.

Adult↗
PubMed2003

[The introduction of complementary food of children under the age of three years in Tibet of China].

OBJECTIVE: To understand the feeding status of Tibetan children aged below three years old. METHODS: Cross-sectional study and randomly sampling were used. The information on complementary food was obtained through the recollection from mother of the child. Data of complementary food of Tibet children was compared with those of the children from the surveys of nine cities in China and 40 poor counties in western China. RESULTS: One thousand six hundred and fifty-five children were studied. The findings indicated that the age of introduction of Zanba (a kind food of mixture of highland barley flour and butter) was 1.98 months after birth and the age of introduction of egg and meat was about 8 - 9 months. Boys were fed with Zanba earlier than girls but there was no significant difference in the introduction of other complementary food between sexes. Urban children were introduced with complementary food earlier than rural children, and children in the agricultural region earlier than those in the pasturing region. The proportion of no introduction of any complementary food by the age of 4 months was about 10.6% for urban children, but 21.7% for rural children while 14.2% for children in the agricultural region and 30.9% for children in the pasturing region. The proportion of no introduction of complementary food was 11.5% for Tibetan children compared with 45.2% for the children of 40 poor counties in western China. The proportions of introduction of the following complementary foods were 89.1% for Zanba, 22.1% for egg, 29.1% for fresh milk, 23.5% for meat, 17.5% for vegetable, 0.75% for bean products, 1.03% for fish and 3.35% for chicken respectively. CONCLUSIONS: The main complementary foods for Tibetan children included Zanba, milk, mutton and beef. There was a small amount of vegetable in diet. The introduction of bean, chicken and fish was not common. Early and monotony seemed to be the character of introduction of complementary food for Tibetan children. Improving introduction of complementary food is important in enhancing the nutritional status of Tibetan children.

Child Nutritional Physiological Phenomena↗
PubMed2003

Changes of indocyanine green and fluorescein angiography in multiple evanescent White-dot Syndrome: a case report.

PURPOSE: To study the clinicopathological change on "Multiple Evanescent White-dot Syndrome (MEWDS)" through fundus angiography analyses. METHODS: Examining the case with fluorescein angiography (FFA) and indocyanine green angiography (ICGA), visual field and following up for 15 months. RESULTS: There exist multiple white dots in the fundus photo and angiography. The changes on ICGA maintain longer than fundus photo and FFA. Papillae may be edematous and macula could present with special hypofluorescent flecks. CONCLUSIONS: MEWDS has specific angiographic features. Its pathological changes involve deep retinal pigment epithelium (RPE) as well as choroidal capillaries. The prognosis of the visual acuity for MEWDS is very good.

Adult↗
PubMed2003

[Change of alpha-crystallin acting as molecular chaperone activity with ageing].

PURPOSE: To evaluate the molecular chaperone function of alpha-crystallin with ageing. METHODS: alpha-Crystallin of newborn, adult and old rabbits lenses in both of cortex and nucleus were separated by chromatography on Sephacryl S-300HR. The protection of alpha-crystallin against thermal aggregation of catalase and beta L-crystallin (60 degrees C), inactivation of catalase by fructose(37 degrees C) and heat stress(60 degrees C) were measured spectrophotometrically. RESULTS: Protection of alpha-crystallin against aggregation and inactivation using four methods showed a similar pattern. The protective ability in cortex was greatly higher than in nucleus of different-aged lenses, and alpha H-crystallin was less than alpha L-crystallin in both cortex and nucleus. There was no statistically decrease with age of chaperone function of both alpha H-crystallin and alpha L-crystallin in the cortex, whereas alpha L-crystallin in the nucleus was compromised. CONCLUSION: alpha-Crystallin in the nucleus shows age-related decrease in chaperone function, which may be responsible for cataract formation.

Aging↗
PubMed2003

[Study on the hemoglobin levels of children under the age of three years and the prevalence of anemia at high altitude in Tibet of China].

OBJECTIVE: To study the hemoglobin status of children under the age of three years and the prevalence of anemia at high altitude. METHODS: Cross-sectional study and randomly sampling were used. Blood was collected on tip of finger and the level of hemoglobin was measured using B-Hemoglobin photometer. We adjusted the hemoglobin based on altitude, using three methods of CDC, Direen's and Dallman's and then estimated the prevalence of anemia. RESULTS: (1) 1 127 children were examined. The findings indicated that the average hemoglobin was about 120 g/L. There was no significant difference for Hb between boys and girls. Urban children had a higher hemoglobin level (123.3 g/L) than rural children (119.9 g/L). Analysis of covariance indicated that, after controlling the factor of altitude, the mean content of hemoglobin of rural children was lower than that of urban children and hemoglobin varied among districts. (2) Different method used for correction of hemoglobin caused different prevalence rates of anemia but they were higher than un-corrected prevalences: 90.4% for CDC method, 72.3% for Dirren's method and 65.0% for Dallman's method respectively. CONCLUSION: Higher altitude seemed to affect the levels of hemoglobin significantly. The prevalence of anemia in children might be higher, but current hemoglobin correction methods might not be suitable for correcting hemoglobin of Tibetan children. So we suggested that it was imperative to establish a relationship between altitude and hemoglobin of Tibetan children.

Age Factors↗
PubMed2003

[Development of impact acceleration measurement facility in return-cabin of spacecraft].

OBJECTIVE: To provide the basis for medical evaluation of spacecraft, and to measure the impact acceleration of return-cabin of spacecraft. METHOD: A facility to measure the impact acceleration of "SZ-3" and "SZ-4" during landing was developed and the acquired test data were analyzed. RESULT: The data of impact acceleration of return-cabins of "SZ-3" and "SZ-4" were accurately recorded during landing. Most reliable and scientific data were gotten. CONCLUSION: This facility could validate and evaluate the specifications of relevant systems of spacecraft, and provided the scientific basis for the decision if "SZ-5", the manned spacecraft, could be launched.

Acceleration↗
PubMed2003

[Method of heart rate variability analysis and its application in the field of space medicine].

The analysis of Heart Rate Variability (HRV), as a noninvasive method in detecting function hearts has been applied widely and is a hot spot for ECG signal processing for its capability to assess function of autonomic nervous system and intrinsic dynamic mechanism of heart quantitatively, and to explain and predict the heart movements. In the present, the method of analysis of HRV signal mainly lies in linear analysis and nonlinear analysis. Research progress of several methods of HRV analysis is presented. And expectation is presented to the analysis of HRV signal and its application in the field of space medicine in the future.

Aerospace Medicine↗
PubMed2003

[Image analysis of cardiac muscle cytoskeleton under simulated microgravity based on gray-level co-occurrence matrix (GLCM)].

OBJECTIVE: To study morphological changes of the cytoskeleton-microtubule (MT) of the fetal rat cardiac myocytes under simulated microgravity, and to quantify its image by utilizing the gray level co-occurrence matrix (GLCM) parameters of the image. METHOD: Cytoskeleton images, including cellular microphotographs taken under normal or microgravity (clinostat) conditions, were quantified by gray level co-occurrence matrix parameters, and the pharmacological counter effect of quercetin against the influences of microgravity was estimated with these parameters. RESULT: The results showed that the texture of microtubules in the image became worse under simulated microgravity environment. It also showed that quercetin has certain counter effect against the influence of microgravity. CONCLUSION: The microtubule of the cardiac myocytes cytoskeleton becomes diffused under microgravity, and the GLCM parameters can well describe these variation. Quercetin has certain counter-effect against the influence of microgravity.

Animals↗
PubMed2002

Facile hydrometalation of alkynes by nido-1,2-(CpRuH)(2)B(3)H(7) yielding novel Ru-B edge-bridging alkylidenes. Stepwise conversion of HCtbd1;CC(O)OMe into nido-1,2-(CpRuH)(2)-3-HOB-4-MeC-5-MeOC-BH(3), Cp = eta(5)-C(5)Me(5).

The reaction of the alkyne HCCC(O)OMe with 7 sep 1,2-(Cp*RuH)2B3H7 leads to hydroboration plus hydroruthenation to produce nido-1,3-mu-Me{C(O)OMe}C-1,2-(Cp*Ru)2B3H7, a compound with an exocluster ruthenium-boron mu-alkylidene that exists in two isomeric forms. Both isomers undergo rearrangement with intramolecular chelation of the carbonyl oxygen at a boron site, thereby opening the cluster and generating arachno-2,3,-mu(C)-5-eta1(O)-Me{C(O)OMe}C-1,2-(Cp*Ru)2B3H7. Further heating leads to deoxygenation of the carbonyl fragment by a boron center concurrent with insertion of the carbon atom into the metallaborane cage to give nido-1,2-(Cp*RuH)2-3-HOB-4-MeC-5-MeOC-BH3.

Journal Article↗
PubMed2002

Extraction of natural vitamin E from wheat germ by supercritical carbon dioxide.

An efficient supercritical fluid extraction (SFE) process with carbon dioxide (SFE-CO(2)) was developed for the extraction of natural vitamin E (V(E)) from wheat germ. Both the pretreatment of extracted wheat germ and extraction conditions were optimized to ensure maximal V(E) yield. The extraction was undertaken at the extracting pressure of 4000-5000 psi, the extracting temperature of 40-45 degrees C, and the carbon dioxide flow rate of 2.0 mL/min for 90 min. An optimized pretreatment of wheat germ was usually necessary with a particle size of 30 mesh and a moisture content of 5.1%. A yield comparison of V(E) and its isomers extracted by supercritical CO(2) with those by conventional solvent extraction suggested that this SFE process was a practical process prospectively superior to conventional solvent extraction to prepare V(E) from wheat germ.

Carbon Dioxide↗
PubMed2002

Metal-induced B-H activation: addition of acetylene, propyne, or 3-methoxypropyne to Rh(Cp*), Ir(Cp*), Ru(p-cymene), and Os(p-cymene) half-sandwich complexes containing a chelating 1,2-dicarba-closo-dodecaborane-1,2-dichalcogenolato ligand.

The addition reactions of the 16e half-sandwich complexes [M(eta5-Cp*)[E2C2(B10H10)]] (Cp*=pentamethylcyclopentadienyl: 1S: E=S, M=Rh; 2S: E=S; M=Ir; 2Se: E=Se, M=Ir) and [M(eta6-p-cymene)[S2C2(B10H10)]] (p-cymene=4-isopropyltoluene; 3S: M=Ru; 4S: M=Os), with acetylene, propyne, and 3-methoxypropyne lead to the 18e complexes 5-19 with a metal-boron bond in each case. The reactions start with an insertion of the alkyne into one of the metal-chalcogen bonds, followed by B-H activation, transfer of one hydrogen atom from the carborane via the metal to the terminal carbon of the alkyne, and concomitant ortho-metalation of the carborane. The E-eta2-CC and the C(1)B units are arranged either cisoid or transoid at the metal. X-ray structural analyses are reported for one of the starting 16e complexes (4S), the cisoid complex 12S (from 2S and HC[triple bond]C-CH3), and the transoid complexes 9S and 14S (from 1S and HC[triple bond]C-CH2OMe, and from 3S and HC[triple bond]CH, respectively). All new complexes 5-19 were characterized by NMR spectroscopy (1H, 11B, 13C, and 77Se and 103Rh NMR spectroscopy when appropriate).

Journal Article↗
PubMed2002

[The application of CY7C09449 in interface between DSP and the PCI bus].

Objective. To introduce the usage of CY7C09449 in the interface between DSP and the PCI bus. Method. The function of a system using CY7C09449 was introduced. Result. The data transmission between PCI bus and DSP was realized. It is proved that the maximum data rate reaches 65Mb/s. Conclusion. It is showed convenient to realize the connection to DSP with CY7C09449 [correction of EY7C09449] and the peripheral circuits is simple.

Computer Peripherals↗
PubMed2002

[Effect of tea polypheonls and ascorbic acid on the activity of antioxidant enzymes in rats with experimental silicosis].

To explore the effect of tea polypheonls (TP) combined with ascorbic acid on the activity of antioxidant enzymes of rats induced by silica, the activities of nitric oxide synthase (NOS), glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) were determined. Compared with the normal saline control group, the activities of SOD and NOS of the silica-induced group increased (P < 0.05), but the activity of GSH-PX was gradually decreased. The activities of SOD and NOS decreased and GSH-PX increased in the intervention group. It is concluded that TP combined with ascorbic acid can alleviate the abnormal change of antioxidant enzymes in rats induced by silica.

Animals↗
PubMed2002

[Effect of deltamethrin on benzyloxyresorufin O-dealkylatase activity and CYP2B1/2B2 protein level in rat brain].

OBJECTIVE: To detect the effect of deltamethrin (DM) on benzyloxyresorufin O-dealkylatase (BROD) activity and the expression of CYP2B1/2B2 in rat brain. METHODS: BROD activity was determined by fluorophotometry under the treatment of DM in vivo and vitro. Western-blot analysis was used to detect the expression of CYP2B1/2B2. RESULTS: In vivo, DM could markedly inhibit BROD activity in rat brain microsome after rats had been treated with DM (12.5 mg.kg-1.d-1, i.p.) for 5 days. The inhibitory rate in whole brain, cerebral cortex and cerebellum were 26.7%, 23.8% and 33.3% respectively(P < 0.05). However, in vitro, under the concentration of 2 x 10(-8)-2 x 10(-4) mol/L of DM, there was no obvious change of BROD activity in rat brain. Moreover, Western-blot analysis indicated that DM could significantly reduce the expression of CYP2B1/2B2 in vivo, the inhibitory rate of protein synthesis was 42.6%. CONCLUSION: DM could inhibit BROD activity in rat brain and this effect may be related to the reduction of CYP2B1/2B2 protein synthesis.

Animals↗
PubMed2002

[Angiographic changes in optic disc and its surrounding choroid after contusion of optic nerve].

PURPOSE: To study the angiographic changes in the optic disc and its surrounding choroidoretina after optic nerve contusion with fundus fluorescein angiography (FFA), and indocyanine green angiography (ICGA). METHODS: Thirty patients (30 eyes) with various degree of optic nerve damage caused by ocular contusion were examined with FFA and ICGA. (The choroidal rupture were excluded in this study). RESULTS: All patients present some abnormal angiography except one case. The main findings in FFA were hypofluorescein on quadrantal or entire disc in the early phase and leakage or persistent nonperfusion in the late phase. Meanwhile, the choroid surrounding disc was clearly delayed in its choroidal filling time. The retinal pigment epithelium (RPE) damage was observed over the localized abnormally perfused choroid. However, the RPE above the circular area around the disc which was hypofluorescein in ICGA showed no RPE damage in 9 cases. There are 2 cases combined with branche retinal vein occlusion and 19 (63%) cases showed ischemic changes exactly on the location of so-called "water separating zone". The visual acuity was not more than 0.1 in 80% of the patients in this study. CONCLUSIONS: There is severe optic nerve lesion in the strong ocular contusion, in which the choroidal and retinal arterial circulation has also been seriously damaged. The FFA and ICGA should be conducted in time in order to judge the injury correctly and allow the clinician to better manage the cases.

Adolescent↗
PubMed2002

Indocyanine green angiographic and multifocal electroretinographic features in the diffuse and regional form of Bietti's crystalline retinopathy.

PURPOSE: To observe different features of indocyanine green angiography (ICGA) and multifocal electroretinography (ERG) in the diffuse and regional type of Bietti's crystalline retinopathy (BCR). METHODS: ICGA and the multifocal ERG were performed in two cases of the diffuse and regional type of BCR respectively. These data were compared with fluorescein angiography (FA), standard Ganzfeld ERG, and visual field testing. RESULTS: In the regional case, ICGA revealed reduced perfusion of the choroidal circulation in the early phase and multiple hypofluorescent spots in the posterior pole in the late phase, due to choriocapillaris filling defect; the extent of choroiocapillaris loss was shown in early phase of ICGA and there were multifocal hyperfluorescent dots surrounding hypofluorescent spots in late phase in the diffuse case. The multifocal ERG showed that the central responses were markedly depressed, corresponding to the visual field defects, while the findings of Ganzfeld ERG were normal in the regional BCR; however, both the multifocal ERG and Ganzfeld ERG were severely subnormal in the diffuse case. CONCLUSIONS: The features of ICGA and multifocal ERG are different between the diffuse and regional BCR. In the meantime, the two tools are also useful to differentiate the type and assess the extent of evolution in BCR.

Adult↗