Biomedical subjects

Yang Lu

Publications and source records attributed to Yang Lu.

At least 73 records · Page 4Linked to original sources

PubMed2005

NANOG changes in mouse kidneys with age.

NANOG is essential for mouse and human embryonic stem cell (ESC) pluripotency and selfrenewal. It is also expressed in several adult murine tissues as shown by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. However, human NANOG transcripts have been isolated from adult bone marrow (EST; GenBank accession no. BF893620). Here, we study the NANOG gene expression profile in isolated mouse renal papillary cells by Northern blot and RT-PCR. The whole RNA of mouse renal cells was obtained from fresh renal tissues, renal tissues infused by phosphate-buffered saline (PBS), and isolated renal papillary cells of mouse, respectively, as well as the renal papillary tissue from 18.5 days postcoitum (d.p.c.; fetal), 1-2-week-old (young), 1-8-month-old (adult), and 24-month-old (aging) mice. Our analysis shows that a very low expression level was detected in mouse renal tissues, and the renal papillary cells express more than other tissues as determined with Northern blot and RT-PCR. These data suggest that the kidney has its own cells expressing NANOG, and loss of NANOG expression occurs in an age-dependent manner in the kidney, either due to developmental factors or aging, particularly in renal papillary tissue.

Aging↗

PubMed2005

Effects of human Na(+)/dicarboxylate cotransporter 3 on the replicative senescence of human embryonic lung diploid fibroblasts.

To investigate the role of human Na(+)/dicarboxylate cotransporter 3 (hNaDC3) in the replicative senescence of normal human embryonic lung diploid fibroblasts (WI-38), a retroviral vector containing hNaDC3 was constructed. hNaDC3 was introduced into normal WI-38 cells through infection with the retroviral virus. Monoclones were selected with G418. The integration and expression of exotic genes were confirmed by Northern blot and Western blot. When compared with the control cells, WI-38 cells transfected with hNaDC3 cDNA showed significant suppression of growth rate (by 40%), increase of positive rate of SA-beta-gal staining, decrease of mitochondrial membrane potential, shortening of telomere length, and increase of P16 and P21 expression. The morphology characteristics of senescent fibroblasts appeared earlier. Our results have, for the first time, demonstrated that high expression of hNaDC3 may be able to, at least partly, promote the cellular senescence of human diploid fibroblasts.

Blotting, Northern↗

PubMed2005

Mitochondrial pathway is responsible for aging-related increase of tubular cell apoptosis in renal ischemia/reperfusion injury.

Aging-related changes of tubular cell apoptosis and its mechanisms in renal ischemia/reperfusion (I/R) injury are unclear. In the present study, aged (27-month-old) and young (3-month-old) Wistar rats were used to investigate aging-related tubular cell apoptosis in the setting of renal I/R injury. The renal I/R model was induced by clamping bilateral renal arteries for 30 minutes followed by reperfusion for 18 hours. Cyclosporine A (CsA, 2 mg/kg) or mycophenolate mofetil (MMF, 20 mg/kg/d) was used before ischemia. Age-matched sham-operated rats served as controls. We found that tubular cell apoptosis increased more significantly in aged rats than in young rats after renal I/R. More pronounced increases of Bax/Bcl-2 ratio, cytosolic cytochrome c, and caspase-9, which are involved in mitochondria-mediated apoptosis, were found in aged rats than in young rats, and were associated with a more pronounced decrease in superoxide dismutase activity and increase of malondialdehyde content. However, increases of tumor necrosis factor-alpha and caspase-8, two components of death receptor-mediated apoptosis, showed no aging-related differences. Interfering mitochondria and death receptor pathways with CsA and MMF, respectively, reduced the apoptosis in both age groups, whereas CsA was more effective in aged rats. Our results have demonstrated that there was an aging-related increase of tubular cell apoptosis in the renal I/R model, which may be, at least partly, due to an enhanced mitochondrial pathway resulting possibly from increased oxidative stress.

Aging↗

PubMed2005

Effects of alterations of glomerular fibrin deposition on renal inflammation in rats at different age stages.

Recent data indicated that aging accelerated glomerular fibrin deposition induced by lipopolysaccharide (LPS) in mice. Our hypothesis was that aging may exacerbate glomerular inflammatory responses induced by glomerular fibrin deposition. Both young and aged rats with glomerular fibrin deposition induced by LPS were treated with tranexamic acid (TA) and TA plus urokinase (UK). Infiltrating inflammatory cells and expressions of monocyte chemoattractant protein 1, intercellular adhesion molecule 1, and vascular endothelial-cadherin were markedly upregulated in the LPS+TA group compared with the LPS group. Reduction of fibrin deposition in the LPS+TA+UK group was associated with downregulation of the above indices (p < .05), whereas the alteration of vascular endothelial-cadherin protein expression was negatively correlated with the fibrin deposition. There were also significant differences in increased expressions of monocyte chemoattractant protein 1 and intercellular adhesion molecule 1 between young and aged rats. These in vivo data demonstrated that fibrin deposition contributed to glomerular inflammatory responses, which could be exacerbated by aging.

Aging↗

PubMed2005

Comparison of a new immunochromatographic test to enzyme-linked immunosorbent assay for rapid detection of immunoglobulin m antibodies to hepatitis e virus in human sera.

An immunochromatographic test for rapid detection of IgM antibodies in patients with acute hepatitis E infection was developed utilizing the well-characterized recombinant protein EP2.1 and monoclonal antibody 4B2. The new rapid test based on a novel reverse-flow technology was able to generate a positive result within 2 to 3 min. Our study showed that this test was able to detect anti-HEV IgM antibodies in 96.7% of the patient samples tested (n = 151) while maintaining an excellent specificity of 98.6% with samples from various patient or healthy control groups (total n = 208). Furthermore, this rapid test gave a good specificity of 90.9% when tested with rheumatoid factor (RF)-positive sera (RF value of < or =850 IU/ml; n = 11) although a higher concentration of RF in samples might cause cross-reactivity. The new test has a good agreement of 97.2% with a kappa value of 0.943 when compared with a reference enzyme-linked immunosorbent assay. The positive predictive value and the negative predictive value for the rapid test thus reached 98.0 and 97.6%, respectively. This is the first rapid, point-of-care test for hepatitis E and will be especially useful for the diagnosis of acute hepatitis E virus infection in field and emergency settings and in resource-poor countries.

Antibodies, Viral↗

PubMed2005

[Propofol reduces intercellular adhesion molecular-1 expression in lung injury following intestinal ischemia/reperfusion in rats].

OBJECTIVE: To investigate the effect of propofol on intercellular adhesion molecular-1 (ICAM-1) expression in the lung tissue following intestinal ischemia/reperfusion (I/R) in rats. METHODS: SD rats were randomly divided into 4 groups (n=8 in each group). (1) Group I/R in which rats were subjected to 1 hour of occlusion of the superior mesenteric artery (SMA), followed by 2 hours of reperfusion. (2) Early treatment group (group P1), rats were subjected to the same procedure as group I/R with the additional administration of propofol beginning 10 minutes before ischemia with 10 mg/kg loading dose, followed by continuous infusion at 10 mg(-1).kg(-1).h(-1). (3) Treatment group (group P2), rats were subjected identical insult as in group I/R with the administration of propofol started 10 minutes before reperfusion with 10 mg/kg loading dose, followed by continuous infusion at 10 mg.kg(-1).h(-1). (4) Sham-operation group, rats were subjected to laparotomy only, but received normal saline at 10 ml.kg(-1).h(-1). At the end of reperfusion, all animals were sacrificed. The activity of myeloperoxidase (MPO) and the content of tumor necrosis factor-alpha (TNF-alpha) were determined in the lung tissue, and plasma TNF-alpha content was also quantified. The ICAM-1 expression in pulmonary endothelium was assessed by histochemical staining. RESULTS: All animals subjected to intestinal I/R demonstrated an increase in TNF-alpha in plasma and lung tissue, MPO activity and ICAM-1 expression in lung tissue. It was much more pronounced in I/R group. Plasma TNF-alpha content was increased significantly in group I/R and P2. All the increase was less in quantity in the early treatment group of propofol than the other two groups, and there was significant difference in contents of plasma TNF-alpha and ICAM-1 expression in lung between group I/R and group P1(both P<0.05). CONCLUSION: ICAM-1 plays an important role in lung injury after intestinal I/R. The early treatment of propofol before intestinal I/R may be beneficial by reducing ICAM-1 expression in lung injury.

Animals↗

PubMed2005

[Study on the active protein fractions from scorpii tegument].

OBJECTIVE: Extracting the total protein from scorpii tegument, investigating its effect on immune system by transformation of T/B cell. METHOD: Water-soluble protein(ST1) was extracted by distilled water method and salting-out method, while keratin(ST2) by deoxidization method. Sephadex G-50 was used to isolate the protein. The effects of components isolated by sephadex G-50 on T/B and NK cell were investigated. RESULT: The protein from scorpii tegument could increase the transformation of T/B cell distinctly in vitro, while no apparent effect on NK cell. CONCLUSION: Protein from scorpii tegument could modulate the immune system, which may offer a new way for people to find protein drugs.

Animals↗

PubMed2005

Evaluation of a new rapid immunochromatographic assay for serodiagnosis of acute hepatitis E infection.

A rapid and reliable diagnostic assay for acute hepatitis E virus (HEV) infection is needed. We evaluated a rapid, immunochromatographic assay for IgM antibodies to HEV (ASSURE HEV IgM Rapid Test) using acute-phase HEV samples (n = 200) from Indonesia and Nepal and convalescent-phase HEV samples (n = 70) from Nepal. Blood donors in Thailand (n = 100), individuals with hepatitis A (n = 80), hepatitis B (n = 45), and hepatitis C (n = 50) in Thailand and Nepal, acute-phase sera of individuals with Epstein-Barr virus infection (n = 20), and rheumatoid factor-positive blood (n = 26) served as negative controls. The assay had a sensitivity of 93% (95% confidence interval [CI] = 88.5-96.1%) and a specificity of 99.7% (95% CI = 98.3-100%). The positive and negative predictive values were 99.5% (95% CI = 97.1-100%) and 95.8% (95% CI = 93.1-97.7%), respectively. These results suggest that this assay is a sensitive and specific tool for the rapid diagnosis of acute HEV infection.

Acute Disease↗

PubMed2004

Anthraquinones sensitize tumor cells to arsenic cytotoxicity in vitro and in vivo via reactive oxygen species-mediated dual regulation of apoptosis.

Cellular oxidation/reduction state affects the cytotoxicity of a number of chemotherapeutic agents, including arsenic trioxide. Reactive oxygen species (ROS), the major intracellular oxidants, may be a determinant of cellular susceptibility to arsenic. Our previous studies showed that a naphthoquinone and an anthraquinone (emodin) displayed the capability of producing ROS and facilitating arsenic cytotoxicity in both leukemia and solid tumor cell lines. We therefore attempted to test emodin and several other kinds of anthraquinone derivatives on EC/CUHK1, a cell line derived from esophageal carcinoma, and on a nude mouse model, with regard to their effects and mechanisms. Results showed that anthraquinones could produce ROS and sensitize tumor cells to arsenic both in vivo and in vitro. The combination of emodin and arsenic promoted the major apoptotic signaling events, i.e., the collapse of the mitochondrial transmembrane potential, the release of cytochrome c, and the activation of caspases 9 and 3. Meanwhile a combination of emodin and arsenic suppressed the activation of transcription factor NF-kappaB and downregulated the expression of a NF-kappaB-specific antiapoptotic protein, survivin. These two aspects could be antagonized by the antioxidant N-acetyl-L-cysteine. Therefore anthraquinones exert their effects via a ROS-mediated dual regulation, i.e., the enhancement of proapoptosis and the simultaneous inhibition of antiapoptosis. In vivo study showed that emodin made the EC/CUHK1 cell-derived tumors more sensitive to arsenic trioxide with no additional systemic toxicity and side effects. Taken together, these results suggest an innovative and safe chemotherapeutic strategy that uses natural anthraquinone derivatives as ROS generators to increase the susceptibility of tumor cells to cytotoxic therapeutic agents.

Animals↗

PubMed2004

Maoecrystal V, cytotoxic diterpenoid with a novel C19 skeleton from Isodon eriocalyx (Dunn.) hara.

Maoecrystal V (1), a novel C(19) diterpenoid possessing a unique 6,7-seco-6-nor-15(8-->9)-abeo-5,8-epoxy-ent-kaurane skeleton, was isolated from the leaves of a Chinese medicinal herb, Isodon eriocalyx. Its structure was determined by comprehensive NMR and MS spectroscopic analysis and confirmed by single-crystal X-ray diffraction study. Compound 1 showed remarkable inhibitory activity toward HeLa cells with IC(50) = 0.02 microg/mL (cis-platin: IC(50) = 0.99 microg/mL).

Crystallography, X-Ray↗

PubMed2004

In vitro anti-coxsackievirus B(3) effect of ethyl acetate extract of Tian-hua-fen.

AIM: To investigation the anti-coxsackievirus B(3) (CVB(3m)) effect of the ethyl acetate extract of Tian-hua-fen on HeLa cells infected with CVB(3m). METHODS: HeLa cells were infected with CVB(3m) and the cytopathic effects (CPE) were observed through light microscope and crystal violet staining on 96-well plate and A(600) was detected using spectrophotometer. The protective effect of the extract to HeLa cells and the mechanism of the effect were also evaluated through the change of CPE and value of A(600). RESULTS: The extract had some toxicity to HeLa cells at a higher concentration while had a marked inhibitory effect on cell pathological changes at a lower concentration. Consistent results were got through these two methods. We also investigated the mechanism of its anti-CVB(3m) effect and the results indicated that the extract represented an inhibitory effect through all the processes of CVB(3m) attachment, entry, biosynthesis and assemble in cells. CONCLUSION: The results demonstrate that the ethyl acetate extract of Tian-hua-fen has a significant protective effect on HeLa cells infected with CVB(3m) in a dose-dependent manner and this effect exists through the process of CVB(3m) attachment, entry, biosynthesis and assemble in cells, suggesting that the ethyl acetate extract of Tian-hua-fen can be developed as an anti-virus agent.

Acetates↗

PubMed2004

[Significance of imbalance between matrix metalloproteinases and tissue type inhibitor of metalloproteinases in renal tubulointerstitial lesions of aging rats].

OBJECTIVE: To explore the imbalance between the expression of metalloproteinases (MMPs) and that of tissue type inhibitors of metalloproteinase (TIMPs) in the renal tubulointerstitial lesions of aging rats and the potential role of this imbalance. METHODS: Forty-eight male 26-month-old Wistar rats were randomly divided into 2 groups of 24 rats: unilateral ureteral obstruction (UUO) group with the left ureter ligated and excised and false operation group used as control group. Forty-eight male 3-month-old Wistar rats were randomly divided into 2 groups of 24 rats: UUO group and false operation group just as in the 26-month-old rats. Every group was randomly divided into 3 subgroups of 8 rats: 3-day group, 7-day group, and 14-day group to be killed 2, 7, and 14 days after the operation respectively. The 2 kidneys of each rat were taken out. Routine pathological examination and immunofluorescence (IF) examination were made to calculate the area of renal tubulointerstitial fibrosis and the expression of IV type collagen. RT-PCR and Western blotting were used to detect the expressions of mRNA and protein of TIMP-1, TIMP-2, MMP-2, and MMP-9 in the kidney at different time points. Gelatin zymography was used to detect the proteolytic activity of MMP-2 and MMP-9. RESULTS: The renal interstitial lesion was more significantly in the 26-month-old UUO rats than in the 3-month-old UUO rats since the 3rd day after operation. Both the expression of MMP-2 mRNA and the expression of MMP-9 mRNA were not different between the 2 control groups. In the control groups, TIMP-1 and TIMP-2 Both MMP-2 mRNA and MMP-9 mRNA were expressed in both control groups, without significant differences between these 2 control groups. TIMP-1 mRNA and TIMP-2 mRNA were only weakly expressed in the renal tissues of the 3-month-old control group, however, the expressions of both TIMP-1 and TIMP-2 were significantly stronger in the 16-month-old control group than in the 3-month-old control group. The expressions of TIMP-1 mRNA and TIMP-2 mRNA at different time points were significantly stronger in the obstructed side than in the healthy side in the UUO groups, and significantly stronger in the 26-month-old rats than in the 3-month-old rats. MMP-2 protein and MMP-9 protein were expressed in the 3-month-old and 26-month-old controls without difference between them. The expressions of MMP-2 protein and MMP-9 protein at different time points were significantly stronger in the obstructed side than in the healthy side in the UUO groups, without significant difference between the 26-month-old UUO rats and the 3-month-old UUO rats. The expressions of TIMP-1 protein and TIMP-2 protein were very weak at different time points in the renal tissues of the 3-month-old controls and were significantly stronger in the 26-month-old control rats. In the UUO rats the expressions of TIMP-1 protein and TIMP-2 protein in the renal tissues of the obstructed side at different time points were all significantly stronger for both age groups in comparison with the control groups of the same age and were significantly stronger in the 26-month-old UUO rats than in the 3-month-old UUO rats without significant difference between the 26-month-old UUO rats and the 3-month-old UUO rats. The MMP-2 activity and MMP-9 activity of the 26-month-old rats were both significantly lower than those of the 3-month-old control rats. The MMP-2 activity and MMP-9 activity at different time points of the 2 UUO groups were all significantly lower than those of the control groups of the same age, and those of the 26-month-old were significantly lower than those of the 3-month-old rats The MMP-2 activity and MMP-9 activity were negatively correlated with the expressions of TIMP-2 and TIMP-1. CONCLUSION: The abnormal expression of MMPs/TIMPs including higher expression of TIMPs and decreased proteolytic activity of MMPs induced by aging may be one of the factors aggravating the renal tubulointerstitial lesions of aging rats.

Aging↗

PubMed2004

Coriatone and corianlactone, two novel sesquiterpenes from Coriaria nepalensis.

Both coriatone (1). a novel highly oxygenated picrotoxane-type sesquiterpene, and corianlactone (2). with an unprecedented sesquiterpene basic skeleton, named coriane, were isolated from Coriaria nepalensis Wall. The structures of 1 and 2 were determined by analysis of their two-dimensional NMR data, and the structure of 2 was confirmed by X-ray analysis. Compounds 1 and 2 showed no remarkable inhibitory activity toward K(562) cells. They are cytotoxic with IC(50) > 50 microg/mL (cis-platinim: IC(50) = 0.49 microg/mL).

Crystallography, X-Ray↗

PubMed2004

A novel cytotoxic oxetane ent-kauranoid from Isodon japonicus.

A novel ll,20: 1,20-diepoxy-ent-kaurane diterpenoid, maoyecrystal 1 (1), was isolated from Isodan japonicus, and its structure was elucidated by spectroscopic methods and comparison with another new ent-kauranoid, rubescensin W (2) from Isodon rubescens var. taihangensis. The structure of 2 was determined by single crystal X-ray diffraction analysis. A bioassay of their cytotoxity against K562 cells showed that the oxetane group of 1 might be a bioactive moiety.

Antineoplastic Agents, Phytogenic↗

PubMed2004

Cycloartane-type triterpenoids from Sphaerophysa salsula.

Four novel cycloartanes, named sphaerophysone A (1), B (2), C (3) and D (4), were isolated from the ethanol extract of Sphaerophysa salsula (Pall.) DC. The structures were elucidated on the basis of spectral evidence, and the stereochemistry of compound 1 was defined by X-ray crystallographic analysis. Sphaerophysone B (2) may be an artifact formed in the isolation procedure.

Drugs, Chinese Herbal↗

PubMed2004

Recombinant adeno-associated virus as delivery vector for gene therapy--a review.

Recombinant adeno-associated virus (rAAV) is one of the most promising delivery vectors for gene therapy, due to its nonpathogenic property, nonimmunogenecity to host, and broad cell and tissue tropisms. This article summarizes the biological characteristics of AAV; the procedures to prepare, purify, and characterize the rAAV for gene therapy applications; and some of the clinical trials utilizing rAAV as delivery vehicles. Also discussed are the current efforts to modify rAAV to change its tropism, the application of different promoters to accommodate specific transgene expression, and the strategy to expand its capacity.

Animals↗

PubMed2004

Use of viral lysate antigen combined with recombinant protein in Western immunoblot assay as confirmatory test for serodiagnosis of severe acute respiratory syndrome.

A Western immunoblot assay for confirmatory serodiagnosis of severe acute respiratory syndrome (SARS) was developed utilizing viral lysate antigens combined with a recombinant nucleocapsid protein, GST-N (glutathione S-transferase-nucleocapsid) of the SARS coronavirus (SARS-CoV). The viral lysate antigens were separated by electrophoresis and transblotted onto nitrocellulose membranes. The resultant membrane was subsequently added with the GST-N recombinant protein at a specific location. The positions of bands corresponding to some of the structural proteins immobilized on the membrane were then located and verified with mouse or rabbit antisera specific to the respective proteins. The Western immunoblot assay was able to detect antibodies to SARS-CoV in all 40 serum specimens from SARS patients and differentiate the SARS-positive samples from those of the healthy donor or non-SARS patient controls (150 samples) when set criteria were followed. In addition, when the immunoblot was used to test samples considered falsely positive by an in-house-developed SARS-specific enzyme-linked immunosorbent assay, band patterns different from those with samples from SARS patients were obtained.

Adolescent↗

PubMed2004

Establishment of the methods for searching eukaryotic gene cis-regulatory modules.

On the basis of the knowledge of eukaryotic gene regulation, we modified the method in three aspects: (1) Searching the cis-regulatory modules (CRM) according Fasta or Blast sequence with multiple sequence and low E value, followed by mutual scoring of these sequence with Smith-Waterman algorithms and finally by clustering analysis; (2) Searching the transcription factor-binding site using International Union of Pure and Applied Chemistry, Position-Weight Matrix(PWM) and Dyed method; (3) Designing and implementation of data analysis based on the software in Windows 2000 and UNIX using object-oriented technology. The results of analysis of the major histocompatibility complex gene family show that this procedure may accurately locate the regions that contain some of the CRMs.

Computational Biology↗