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Biomedical subjects

Hui Yang

Publications and source records attributed to Hui Yang.

At least 145 records · Page 8Linked to original sources
PubMed2003

[Fluorescence spectroscopic study of interaction between Fe-protoporphyrin in myoglobin and Cu(II) ions].

In this paper, the interaction between Cu(II) ions and Fe-protoporphyrin in horse-heart myoglobin (FePP-Mb) was studied. As a result, some of the Fe(II) ions in FePP-Mb were found to be replaced by Cu(II) ions forming CuPP-Mb, by adding Cu(II) ions into the myoglobin solution. The interaction became stronger when adding more Cu(II) ions into the myoglobin solution. By studying the metal ions' interaction with myoglobin proteins as macromolecules and discussing the interaction mechanism, this work provides a theoretical basis for the further study of hazardous metal ions' interaction with the human body and its mechanism. The fluorescence spectroscopic method used in this study has higher sensitivity than the ordinary UV and CD methods.

Animals↗
PubMed2003

[Effects of manganese with different valences to apoptosis of SH-SY5Y cell].

To study the effect of manganese with different valences to apoptosis, human neuroblastoma cell line (SH-SY5Y) has been chosen to study the induction of Mn2+ and Mn3+ on apoptosis and the content of dopamine in vitro. The results showed that both Mn2+ and Mn3+ induced a time-dependent decrease in SH-SY5Y cell viability, as determined by MMT assay. In the meantime, apoptosis was inducted by flow cytometer analysis (FCAS) after culture of Mn2+ or Mn3+ (0.5-2 mmol/L) with SH-SY5Y cell for 24-72 h. The ultrastructural changes of apoptosis such as nuclear chromosome condensation, was seen by transmission electron microscope. In addition, DA content was decreased by measured with HPLC. The major path of cell death induced by Mn2+ and Mn3+ may be due to apoptosis. Both Mn2+ and Mn3+ could induce the reduction of DA content. All these results suggest that Mn3+ appeared to be more cytotoxic than Mn2+.

Apoptosis↗
PubMed2003

[Effect of lead acetate on the nerve growth factor protein expression and the regulation of thyroid hormone].

OBJECTIVES: To study the effect of lead acetate on the expression of nerve growth factor (NGF) protein in rat brain and the regulation of thyroid hormone. METHODS: Lead acetate was given to SD rats intraperitoneally ip. at the dosage of 25, 50 and 100 mg/kg respectively. 6-n-propyl-2-thiouracil (PTU) was used to make a hypothyroid model and then lead acetate was given at the dosage of 50 mg/kg body weight through i.p. The NGF protein expression in rat brain was observed by immunohistochemistry Triiodothyronine (T3), thyroxin (T4), TSH in serum and T3, T4 in brain tissue were determined by radio immunoassays (RIAs). RESULTS: The average gray value of NGF protein in cerebral cortex of 50 mg, 100 mg treated groups (180.49 +/- 10.33, 169.72 +/- 19.75, respectively) were lower than the control (200.75 +/- 3.27, P<0.01). The area density of NGF protein in hippocampus of three treated groups (0.08 +/- 0.14, 0.12 +/- 0.02, 0.13 +/- 0.04, respectively) were significantly different from the control (0.025 +/- 0.015, P<0.05). The area density and the average gray value of NGF protein in lead acetate treated hypothyroid rat brain were of no significant changes. The levels of serum T3 in three treated groups [(0.68 +/- 0.02), (0.57 +/- 0.04), (0.54 +/- 0.02) microg/L respectively] and T4 [(28.30 +/- 1.83), (27.35 +/- 2.55), (24.00 +/- 3.01) microg/L] in serum were significantly lower while TSH [(6.34 +/- 1.13), (7.74 +/- 0.79), (9.16 +/- 0.77) IU] higher than those in the control [T3 (0.97 +/- 0.14) microg/L, T4 (54.50 +/- 3.70) microg/L and TSH (4.62 +/- 2.16) IU], and there was a good dose-response relationship. The levels of T3 in cerebral cortex of three treated groups [(13.26 +/- 0.81), (11.49 +/- 0.10), (10.42 +/- 1.19) pg/mg pro respectively] and T4 [(0.50 +/- 0.03), (0.49 +/- 0.13), (0.42 +/- 0.01) ng/mg pro] were significantly lower than those in control [(20.85 +/- 11.01) pg/mg pro, (0.76 +/- 0.14) ng/mg pro, P<0.05, P<0.01]. CONCLUSION: Lead could increase the NGF protein expression in rat brain, which may be regulated by thyroid hormone.

Animals↗
PubMed2003

[Effects of varglaucocalyx on c-fos gene expression during global myocardial ischemia-reperfusion in rat].

OBJECTIVE: To determine the effects of Varglaucocalyx on c-fos gene expression during global myocardial ischemia-reperfusion. METHOD: Forty Wistar rats were divided into 5 groups: group N as control; group CN as ischemia-reperfusion control and group XH, XM and XL treated with Varglaucocalyx 5%, 1%, 0.5% respectively prior to ischemia-reperfusion. The isolated rat hearts were perfused in condition of constant temperature and pressure, and then the left ventricular myocardiums were extracted for use. The expression of c-fos protein was detected by immunochemical method. The expression of c-fos protein were quantified by using computer image analysis system. RESULT: Compared with the values of group N, protein expressions relative area of c-fos gene (PERA) were increased significantly in group CN, XH, XM, XL(P < 0.01), but decreased significantly in group XH, XM, XL, compared with those of group CN (P < 0.05). The PERA of c-fos gene in group XM, XL were significantly lower than in group XH (P < 0.01), and the PERA of c-fos gene in group XM were lower than in group XL(P < 0.05). CONCLUSION: Varglaucocalyx can effectively depress the expression of c-fos gene in myocardium which may account for its protection against myocardial ischemia-reperfusion injury, and the middle and the low concentrations of Varglaucocalyx are more effective than the high concentrations.

Animals↗
PubMed2002

Hyperresponsive airways correlate with lung tissue inflammatory cell changes in ozone-exposed rats.

The role of inflammatory cell infiltration in the development of hyperresponsiveness of the airways to muscarinic challenge remains poorly understood. Unlike previous investigations that only examined conducting airway inflammation, the present study utilized both bronchoalveolar lavage (BAL) and lung tissue digestion to determine rat lung inflammatory cell contents following a 4-h exposure to 2 ppm ozone. Immediately following ozone exposure, neutrophil content of the lung tissue was significantly increased and reached a value that was fourfold higher than air-exposed controls by 3 h postexposure. Although lavage-recovered neutrophils were elevated at 24 h, tissue neutrophil numbers had returned to control values. This transient elevation of tissue neutrophils directly correlated with an elevation and subsequent decline of airway hyperresponsiveness, measured as a decrease in the intravenous dose of methacholine provoking a 200% increase in airway resistance (PD(200)R). Animals rendered neutropenic with a rabbit anti-rat neutrophil serum prior to exposure were protected from ozone-induced hyperresponsive airways, further demonstrating an association between neutrophil infiltration into the lung and altered airway physiology. Although BAL-recovered neutrophils demonstrated no adverse effects as a result of ozone exposure, macrophages were not only found to be necrotic but also displayed altered oxidative metabolism when challenged with phorbol myristate acetate. Thus, changes in the microenvironment of the airways smooth muscle were shown to be associated with transient accumulation of neutrophils within the lung tissue and abnormalities of bronchoalveolar lavage-recovered macrophages.

Administration, Inhalation↗
PubMed2002

Characteristics of self-guided laser plasma channels generated by femtosecond laser pulses in air.

With ultrashort laser pulses (25 fs) and low energy (E=15 mJ), we observe laser plasma channels with a length over 5 m in air. The diameter of the plasma channel is measured to be 120 microm. The average electron density in the channel is inferred to be about 10(18) W/cm(3) with an interferometric method. At the same time, the temporal evolution of the electron density in the plasma channel is investigated. The resistivity in the plasma channel is measured to be less than 1 Omega cm. It is suggested that the lifetime of the plasma channel can be greatly prolonged by launching another long laser pulse along the plasma channel.

Journal Article↗
PubMed2002

Activation of Erk1/2 and Akt in astrocytes under ischemia.

Substantial evidence has shown that extracellular signal-regulated kinases 1 and 2 (Erk1/2) and serine/threonine kinase (Akt) play important roles in regulating cell survival. We examined the activities of these kinases in astrocytes under ischemia in an anaerobic chamber. The level of phosphorylated Erk1/2 in astrocytes began to increase after 1 h ischemia, reached a maximum after 4 h ischemia, before decreasing from 5 to 6 h. Akt was activated later than Erk1/2. It was significantly increased after 4 h ischemia before declining steadily afterwards. Lactate dehydrogenase (LDH) assay and Hoechst nucleic staining indicated that U0126, which inhibits Erk1/2 phosphorylation, enhanced ischemia-induced cell death, whereas LY294002, which inhibits Akt phosphorylation, delayed cell death. These effects were dose-dependent. At 4 and 6 h ischemia, U0126-treated astrocytes expressed a lower level of Bcl-2 than controls. In contrast, LY294002-treated astrocytes expressed a higher level of Bcl-2 than controls as shown by Western blots. Bcl-x(L) expression level was not affected by either treatment. These data suggest that activation of the MAPK/Erk1/2 pathway might protect astrocytes from ischemic injury, but activation of the PI3-K/Akt pathway does not. The effect may involve Bcl-2 but not Bcl-x(L) expression.

Animals↗
PubMed2002

Abietane diterpenoids from Coleus xanthanthus.

Eight new abietane diterpenoids, coleon U 11-acetate (1), 16-acetoxycoleon U 11-acetate (2), and xanthanthusins F-K (3-8), together with five known analogues, coleon U (9), 16-O-acetylcoleon C (10), coleon U-quinone (11), 8alpha,9alpha-epoxycoleon U-quinone (12), and xanthanthusin E (13), were isolated from the aerial parts of Coleus xanthanthus. The structures of 1-8 were elucidated on the basis of spectral methods. Compounds 1, 5, and 11-13 were evaluated for their cytotoxicity against K562 human leukemia cells.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Diterpenoids from Isodon adenantha.

Eleven new diterpenoids, adenanthins B-L (1-11), together with five known analogues, calcicolin B (12), adenanthin (13), weisiensin A (14), nervosanin (15), and forrestin C (16), were isolated from the aerial parts of Isodon adenantha. The structures of 1-11 were elucidated on the basis of spectral methods, as well as the X-ray crystallographic analysis of 11. Compounds 2, 5, and 14 showed significant inhibitory activities against K562 cells, with IC(50) values less than 4.0 microg/mL, respectively.

Diterpenes↗
PubMed2002

Dihydroisotanshinone I protects against menadione-induced toxicity in a primary culture of rat hepatocytes.

Dihydroisotanshinone I is a phenanthrenequinone derivative isolated from the roots of Salvia trijuga Diels. The present study demonstrated the hepatoprotective effect of dihydroisotanshinone I against menadione-induced cytotoxicity in a primary culture of rat hepatocytes. Pretreating the cells with dihydroisotanshinone I at concentrations ranging from 2.5 microM to 20 microM for 24 hours caused dose-dependent protection against hepatotoxicity induced by menadione. Intracellular glutathione level and activity of DT-diaphorase have been suggested to play important roles in menadione-induced cytotoxicity. However, treating the hepatocytes with 20 microM dihydroisotanshinone I for 24 hours did not cause a significant change in glutathione level and DT-diaphorase activity. On the contrary, adding dihydroisotanshinone I to freshly isolated hepatocytes at concentrations between 50 nM to 200 nM inhibited NADH-induced superoxide production dose-dependently as indicated by the decrease of lucigenin-amplified chemiluminescence. In addition, dihydroisotanshinone I at concentrations ranging from 5 microM to 20 microM inhibited tert-butyl hydroperoxide-induced lipid peroxidation dose-dependently in isolated hepatocytes as indicated by the level of malondialdehyde. These results suggest that the protective action of dihydroisotanshinone I against menadione-induced hepatotoxicity is attributed to its antioxidant properties including the free radical scavenging activity and inhibition of lipid peroxidation. Abbreviations. DTD:DT-diaphorase GSH:glutathione LDH:lactate dehydrogenase MDA:malondialdehyde MTT:3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide TBHP: tert-butyl hydroperoxide

Animals↗
PubMed2002

Constituents of Clerodendrum bungei.

Two new compounds, 5-O-ethylcleroindicin D (1) and bungein A (2), together with 12 known compounds (3-14), were isolated from the aerial parts of the medicinal plant Clerodendrum bungei. The structures of 1 and 2 were elucidated as a perhydrobenzofuran derivative and a peroxide dimer by spectral and chemical evidence. Compounds 3-14 have been obtained from this species for the first time.

Clerodendrum↗
PubMed2002

Diversity of rotavirus strains among children with acute diarrhea in China: 1998-2000 surveillance study.

As part of a national rotavirus surveillance activity, we collected fecal specimens from 3,177 children with acute diarrhea in 10 regions of China between April 1998 and April 2000 and screened them for rotavirus. Rotavirus was detected in 41% (n = 1,305) of specimens, and in these, G1 was the predominant serotype (72.6%), followed by G3 (14.2%), G2 (12.1%), G4 (2.5%), G9 (0.9%), and G untypeable (0.7%). Among 327 G-typed strains tested for P genotype, 14 different P-G combinations were identified, with the globally common strains P[8]G1, P[4]G2, P[8]G3, and P[8]G4 representing 75.6% of all typed rotavirus strains. Among the uncommon strains, 11 were P[6]G9, and others included P[6]G1, P[6]G3, and five novel P-G combinations (P[9]G1, P[4]G1, P[4]G3, P[4]G4, and P[8]G2). Our results indicate that while the common rotavirus strains remain predominant, the diversity of strains is much greater than was previously recognized.

Acute Disease↗
PubMed2002

[P21(WAF1) inhibits the growth of leukemia cell line K562 and decreases its sensitivity to Vp16].

OBJECTIVE: To explore the effect of p21(WAF1) on the proliferation and the sensitivity to Vp16 of leukemia cell line K562. METHODS: A p21(WAF1) retroviral expression vector pLXSN-p21(WAF1) was constructed by FuGENE 6, pLXSN-p21(WAF1) and pLXSN-neo, and transfected into p21(WAF1) defect leukemia cell line K562. After selected with G418, K562-p21(WAF1) cell clones that stably expressed p21(WAF1) were isolated. The ectopic expressions of p21(WAF1) mRNA and protein in K562-p21(WAF1) were identified by RT-PCR and Western b1ot. The cell growth rate was tested by trypan blue dye, the cell cycle by FCM and the sensitivity to Vpl6 by cell count and MTT assay. RESULTS: The expression of p21(WAF1) protein and mRNA could be detected in K562-p21(WAF1) cells. A strong inhibition of cell proliferation was observed in K562-p21(WAF1) cell as compared with that of the control. The cell number in G(0)/G(1) phase was remarkably increased. The sensitivity to Vpl6 decreased, the IC (50) of K562-neo cells was (56.4 +/- 6.5) microgram/ml, and that of K562-p21(WAF1) cells was (131.0 +/- 8.7) microgram/ml (P < 0.01). CONCLUSION: p21(WAF1) can inhibit the proliferation of leukemia cell and decrease its sensitivity to Vp16.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Cloning expression in E.coli and biological activity of human thymosin beta(4).

The cDNA thymosin beta(4) was synthesized by combining of chemical and enzymatic methods. First, two complement fragments of thymosin beta(4) cDNA were synthesized by DNA synthesizer, and then denatured, annealed and extended by DNA polymerase. This fragment of thymosin beta(4) was then inserted into the EcoRV and HindIII restriction endonuclease site of an expression plasmid pLDH4 (a kind of E.coli plasmid) by blunt and cohesive ligations. Finally, the recombinant plasmid which expressed thymosin beta(4) was screened by digestion and DNA sequencing. This recombinant plasmid highly expressed the thymosin beta(4), which accounted for 30% of total bacteria proteins. By salting out and chromatography, a 95% purity of recombinant thymosin beta(4) was obtained. Biological assay indicated that the recombinant thymosin beta(4) could induce lymphocyte proliferation and differentiation.

Cell Differentiation↗
PubMed2002

[A clinical study of posterior capsular opacification after implantation of foldable intraocular lenses with different edges of optics].

OBJECTIVE: To study the influence of intraocular lens (IOL) optics with a square truncated edge on the incidence of posterior capsular opacification (PCO). METHODS: This consecutive series of 140 eyes (140 cases) underwent phacoemulsification with implantation of a foldable IOL with a square truncated edges (n = 90) or a foldable IOL with a round tapered edges (n = 50). We evaluated visual acuity, overall incidence of PCO and the incidence of PCO under different continuous curvilinear capsulorrhexis (CCC) conditions after surgeries. The mean postoperative follow-up was (14 +/- 8) months (range, 6 to 48 months) and (18 +/- 8) months (range, 6 to 48 months) respectively. RESULTS: Posterior capsular opacification occurred in 8.9% (8/90 eyes) of eyes in the square truncated edge designed group and 38.0% (19/50 eyes) of eyes in the round tapered edge designed group. The difference between the 2 groups was statistically significant (P < 0.01). Moderate CCC with the diameter slightly smaller than that of the IOL optic was achieved in 76 eyes in the square truncated edge group and no PCO was found. In the round tapered edge group, moderate CCC was achieved in 41 eyes in which 10 eyes developed PCO. Amonhad a large or decentered CCC, 8 out of 14 eyes (57.1%) in the square truncated group developed PCO, and 9 out of 9 eyes (100.0%) in the round tapered group developed PCO. The difference is also significant (P < 0.05). Nd: YAG laser capsulotomy rate was lower in the square truncated edge group (1.1%) than that in the round tapered edge group (10.0%) (P < 0.05). CONCLUSION: Moderate CCC and IOL optic design with a square truncated edge are the two important factors for prevention of posterior capsular opacification.

Adult↗
PubMed2002

[p21(WAF1) transfection decreases sensitivity of K562 cells to VP-16].

The objective of this study was to explore the effect of p21(WAF1) on the sensitivity to chemotherapeutic agent VP-16, etoposide, in leukemia cell line K562. A p21(WAF1) retroviral expression vector was constructed, and mediated by FuGENE(TM)6, it was transfected into K562 cells, which without p21(WAF1) expression. The ecotropic expression of p21(WAF1) in K562 cells was identified by RT-PCR and Western blot, and named K562-p21(WAF1) cell. The K562-p21(WAF1) cells were exposed to VP-16 at different concentrations and different times, then, the sensitivity to VP-16 was examined by cell viability and MTT assay, the apoptosis induced by VP-16 was examined by DNA fragments electrophoresis and flow cytometric Annexin V-PI dual labeling technique. The results showed that the ecotropic expression of p21(WAF1) decreased the sensitivity of K562 cells to VP-16. After treatment of VP-16, the DNA ladder was examined in control K562-neo cells at 20 microgram/ml, but in K562-p21(WAF1) cells at 80 microgram/ml. With FCM, the number of apoptotic K562-neo cells was 14.9% and 25.4% respectively after treated with 20 microgram/ml VP-16 for 12 and 24 hours, and it was 6.94% and 10.96% in K562-p21(WAF1) cells. Our results suggest that the expression of p21(WAF1) could reduce the sensitivity of K562 cells to VP-16 and inhibit the apoptosis of K562 cells

Antineoplastic Agents, Phytogenic↗
PubMed2002

Effect of intracameral lidocaine anesthesia on the anterior segment of rabbit eyes.

PURPOSE: To evaluate the effect of intracameral anesthesia on the anterior segment of rabbit eyes using chinese-made lidocaine. METHOD: The study comprised eight eyes of four white rabbits which were divided into three groups according to the concentration of the lidocaine given. They are 0.5%, 1%, 2% lidocaine groups and balanced salt solution (BSS) control group. Each group contained two eyes. After 0.5 ml of the anesthetic agent was injected into the anterior chamber and retained there for ten minutes, the rabbits were executed and the eye balls were enucleated. Pathological examinations of the anterior segment, including cornea, iris and ciliary body, were carried out immediately. RESULT: The pathological study revealed no abnormal findings in lidocaine 0.5% and 1% groups compared with the control group, where as in the lidocaine 2% group, much abnormal pathological change was found, including the shrinkage of corneal endothelium, stroma edema of iris and ciliary body. CONCLUSION: Using intracameral anesthesia of high concentration of chinese-made lidocaine would run a risk of damaging the anterior segment of rabbit eye. But at the low concentration usually used in cataract surgery, no adverse effect was found.

Anesthetics, Local↗