Biomedical subjects

Y Wu

Publications and source records attributed to Y Wu.

At least 451 records · Page 25Linked to original sources

PubMed2000

[Modulation of the inflammatory response through complement-neutrophil activation feedback mechanism with selenium and vitamin E].

To identify the regulatory effect of sodium selenite and vitamin E on the complement-neutrophil-reactive oxygen(ROS) activation feedback (CNAF) mechanism mediated inflammatory response, we detected ROS production and complement activation in vitro tests by chemiluminescence technique and complement fixation and recognized the regulation of the inflammatory response in vivo mouse vasculitis models of skin, lung, and liver. Convincing results were observed as both in vitro and in vivo experiments showing inhibition of CNAF mechanism with sodium selenite and vitamin E could effect the reduced ROS production and complement activation. The incidence (100%) for vasculitis in control group decreased to 20%-57% in sodium selenite and vitamin E treated groups. Elucidation of the ancillary mechanism of CNAF enhancing inflammatory response is a promising area for new therapeutic developments in the modulation of inflammatory response. As in a clinical approach, a remarkable therapeutic effect with sodium selenite was observed during an epidemic episode of epidemic hemorrhagic fever in Henan province. The mortality rate of fulminant cases was reduced from 100% of untreated control cases to 36.6% by treatment with sodium selenite. The results of present studies strongly suggest that antioxidants such as selenium and vitamin E as well as others like flavonoids can exhibit a novel anti-inflammatory action via this CNAF mechanism. It is expected in the future an increasing number of patients with severe infections or inflammatory disorders in which excessive complement activation and adverse ROS production have been implicated, e. g. ischemia-reperfusion injury, severe sepsis and diverse inflammatory vascular injuries like rheumatoid arthritis, hepatitis and inflammatory bowel diseases should benefit from this newer concept guided adjuvant therapies which make use of nutrient antioxidants like selenium, vitamin E and others.

Animals↗

PubMed2000

[DNA damage and c-myc gene expression of NIH3T3 cell induced by superoxide anion].

OBJECTIVE: To study the DNA damage, membrane lipid peroxidation, and c-myc gene expression of NIH3T3 cell induced by superoxide anion(O2.-). METHODS: The superoxide anion(O2.-) was produced by reactive system of xanthine-xanthine oxidase (X-XO) and the DNA-EB complex, malondialdehyde (MDA) content and expression of c-myc gene were measured by means of fluorescence, thiobarbituric acid (TBA) assay and DNA-RNA situ hybridization with digoxigenin labeled probes respectively. RESULTS: The O2.- of high concentration(X: 20 micrograms, XO: 2 x 10(-3) U) reacted with isolated DNA from NIH3T3 cell directly which caused DNA damage obviously. When the O2.- of high concentration reacted with whole NIH3T3 cell, the amount of MDA increased and fluorescence intensity of DNA-EB complex decreased which mean lipid peroxidation of membrane and gene damage of the cell respectively. When the producing O2.- of high concentration reactive system existing FeSO4, the phenomena mentioned above showed obviously. Enough amount of catalase showed the inhibit effects, but it could not completely inhibit the DNA damage of whole cell. The c-myc gene expression was observed in the cell treated with O2.- of middle (X: 4 micrograms, XO: 4 x 10(-4) U) and high concentration, but it was not observed in the cell treated with O2.- of low concentration(X: 0.4 micrograms, XO: 4 x 10(-5) U). CONCLUSIONS: DNA damage of the whole cell induced by extracellular O2.- was able to act through the pathway of membrane lipid peroxidation in which hydrogen peroxide is important and the other pathways such as signal transduction of the cell might also be existed. The expression of c-myc gene of NIH3T3 cell induced by O2.- was related closely to the concentration of O2.-.

Animals↗

PubMed2000

[Study on the role of superoxide anion in promoting proliferation and transformation of rat liver oval cell line WB-E344].

OBJECTIVE: To study the role of superoxide anion (O2.-) in promoting proliferation and transformation of rat liver oval cell strain WB-F344. METHODS: WB-F344 cells cultured were stimulated directly by O2.- generated by interaction of xanthine with xanthine oxidase (X-XO). The effect of O2.- in promoting proliferation of WB cells was investigated by using MTT colorimetric analysis, 3H-Tdr incorporation liquid scintillation counter and 3H-Tdr incorporation autoradiography. WB cells initiated with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) were promoted by stimulating continuously with O2.- of low concentration (X: 100 mumol/L, XO: 0.2 mU/ml). The transformation effect was tested by morphologic observation, karyotype analysis and anchorage-independent growth assay. RESULTS: Proliferation of WB cells was induced obviously by O2.- of low concentration for only one time. WB cells initiated with MNNG were transformed by action with O2.- of low concentration continuously for 15 d and typical morphologic character of transformed cells was observed. In karyotype analysis the cells chromosome number changed and the frequency of structure aberration raised dramatically. Also the transformed cells could form clone on self-solid culture medium. CONCLUSIONS: The biological effect of O2.- was related closely with its dose; The effects of low concentration in promoting proliferation and transformation of liver oval cells indicate its important role in hepatocarcinogenesis and antioxidation was able to provide a new clue in prevention and cure of hepatoma.

Animals↗

PubMed2000

Final report about Stage II Collaboration Project on Leprosy Rehabilitation.

OBJECTIVE: To undertake the pilot experiments of prevention of disability (POD) in 14 different geographical areas to serve as examples for future development of rehabilitation work in China and in Asia. METHODS: According to the principles and national criterion, 27 000 people affected by leprosy were selected and assessed using disability record forms at beginning and followed up regularly for observing changes of different indicators. RESULTS: A total of 197 neuritis cases were detected and treated with prednisolone out of 1 407 new or active cases. Self-care training of eyes, hands and feet were conducted for 10 500 disabled people affected by leprosy. Comprehensive therapy was given to 1 804 cases having complicated ulcers of which 1 055 cases have got their ulcers healed. Out of 706 prostheses, 613 were given to patients with satisfactory results. Surgical treatment was given to 269 cases and 251 have shown good progress. CONCLUSION: Most of patients have got benefit from the project in function or appearance which is very helpful for their going back to the society and agreed by foreign experts during the final evaluation. The experiences from the project can be implemented in the whole country.

China↗

PubMed2000

[Heat-induced dynamics studies of azobenzene containing long-chain fatty acid by two-dimensional correlational Raman spectroscopy].

Temperature-dependent Fourier transform Raman (FT-Raman) spectra were measured in the temperature range between 30 to 120 degrees C for the azobenzene-containing long chain fatty acid 8A5H in the solid state. Generalized two-dimensional (2D) correlation was applied to calculate temperature-dependent synchronous and asynchronous Raman spectra in order to investigate the sequence of the reorientions arising from the different transient moments associated with molecular vibrations induced by temperature.

Azo Compounds↗

PubMed2000

[Changes of trace elements in cells of lung cancer and cervix cancer before apoptosis and after apoptosis].

The sensitivity of total reflection X-ray fluorescence analysis (TXRF) is higher than normal X-ray fluorescence analysis (XRF). The cells of lung cancer and cervix cancer were researched before apoptosis and after apoptosis employed the method of TXRF on new transformed synchrotron radiation XRF experimental station of new 3W1A beam line which built on Beijing Synchrotron Radiation Facility (BSRF) of BEPC (new detector and spectrometer systems). We acquired their fluorescence spectrum of various elements before apoptosis and after apoptosis. We discovered there were interesting results that changes even remarkable changes of some elemental contents had occurred in these cells before apoptosis and after apoptosis. These alterations of elemental contents have served an inspiration for us: if their regularities of change are found, we will hope that some contributions would be done at the treatments of cancer.

Apoptosis↗

PubMed2000

[Discussions on some problems related to fluid inclusion analysis by SXRF].

X-ray fluorescence experiments were carried out at Beijing Synchrotron Radiation Facilities (BSRF) using synchrotron radiation as excitation source. The samples were made by mixing national reference standard GBW07106 and certain amount of reagent NaCl and KCl, and pressed into pellets. The purpose of the experiment is to verify the detection ability of the XRF setup at BSRF for elements in geological samples, especially for light elements. The beam size was 20 x 20 microns2, and the current in the storage ring was about 40 mA. The gap between the sample and the Si(Li) detector was 2 cm. With measuring time of 200 sec., The relative and absolute detection limits for 10 elements have been calculated. The sampling depth and sampling weight, which are critical in individual fluid inclusion analysis, have also been estimated. Some problems concerning the individual fluid inclusion analysis by SXRF, such as inclusion depth determination, effect of the inclusion depth on XRF intensity etc., are discussed based on the experiment results.

English Abstract↗

PubMed1999

A novel human hepatic organic anion transporting polypeptide (OATP2). Identification of a liver-specific human organic anion transporting polypeptide and identification of rat and human hydroxymethylglutaryl-CoA reductase inhibitor transporters.

A novel human organic transporter, OATP2, has been identified that transports taurocholic acid, the adrenal androgen dehydroepiandrosterone sulfate, and thyroid hormone, as well as the hydroxymethylglutaryl-CoA reductase inhibitor, pravastatin. OATP2 is expressed exclusively in liver in contrast to all other known transporter subtypes that are found in both hepatic and nonhepatic tissues. OATP2 is considerably diverged from other family members, sharing only 42% sequence identity with the four other subtypes. Furthermore, unlike other subtypes, OATP2 did not transport digoxin or aldosterone. The rat isoform oatp1 was also shown to transport pravastatin, whereas other members of the OATP family, i.e. rat oatp2, human OATP, and the prostaglandin transporter, did not. Cis-inhibition studies indicate that both OATP2 and roatp1 also transport other statins including lovastatin, simvastatin, and atorvastatin. In summary, OATP2 is a novel organic anion transport protein that has overlapping but not identical substrate specificities with each of the other subtypes and, with its liver-specific expression, represents a functionally distinct OATP isoform. Furthermore, the identification of oatp1 and OATP2 as pravastatin transporters suggests that they are responsible for the hepatic uptake of this liver-specific hydroxymethylglutaryl-CoA reductase inhibitor in rat and man.

Amino Acid Sequence↗

PubMed1999

Ligation of microglial CD40 results in p44/42 mitogen-activated protein kinase-dependent TNF-alpha production that is opposed by TGF-beta 1 and IL-10.

Recently, it has been demonstrated that the CD40 receptor is constitutively expressed on cultured microglia at low levels. Ligation of CD40 by CD40 ligand on these cells results in microglial activation, as measured by TNF-alpha production and neuronal injury. However, the intracellular events mediating this effect have yet to be investigated. We report that ligation of microglial CD40 triggers activation of p44/42 mitogen-activated protein kinase (MAPK). This effect is evident 30 min posttreatment, and progressively declines thereafter (from 30 to 240 min). Phosphorylated p38 MAPK is not observed in response to ligation of microglial CD40 across the time course examined. Inhibition of the upstream activator of p44/42 MAPK, mitogen-activated protein/extracellular signal-related kinase kinase 1/2, with PD98059, decreases phosphorylation of p44/42 MAPK and significantly reduces TNF-alpha release following ligation of microglial CD40. Furthermore, cotreatment of microglial cells with CD40 ligand and TGF-beta1 or IL-10, or both, inhibits CD40-mediated activation of p44/42 MAPK and production of TNF-alpha in a statistically interactive manner. Taken together, these data show that ligation of microglial CD40 triggers TNF-alpha release through the p44/42 MAPK pathway, an effect that can be opposed by TGF-beta1 and IL-10.

Animals↗

PubMed1999

Impaired immunoproteasome assembly and immune responses in PA28-/- mice.

In vitro PA28 binds and activates proteasomes. It is shown here that mice with a disrupted PA28b gene lack PA28a and PA28b polypeptides, demonstrating that PA28 functions as a hetero-oligomer in vivo. Processing of antigenic epitopes derived from exogenous or endogenous antigens is altered in PA28-/- mice. Cytotoxic T lymphocyte responses are impaired, and assembly of immunoproteasomes is greatly inhibited in mice lacking PA28. These results show that PA28 is necessary for immunoproteasome assembly and is required for efficient antigen processing, thus demonstrating the importance of PA28-mediated proteasome function in immune responses.

Animals↗

PubMed1999

Intermittent degradation in performance in schizophrenia.

In a series of repeated trials, schizophrenic patients often fluctuate in performance. Our data suggest that it may be useful, not just to report an increased variance relative to nonschizophrenics, but to model these fluctuations concretely as transitions between a relatively normal and an abnormal cognitive state - an intermittent degradation in performance that may be related to transient abnormalities in CNS functioning. We define 'dialipsis' as a temporary substitution of a less efficient process of task performance. This phenomenon is mentioned in the literature, but the descriptions of dialipsis are heuristic rather than based on a statistical model. We present a mixture model in which the ordinary and degraded states are described by distinct ANOVA structures, each with its own task, subject and interaction effects, with transitions between them occurring at random times. We discuss ways of detecting dialipsis and comparing the mixture model statistically with alternative models.

Analysis of Variance↗

PubMed1999

Inhibition of bcr-abl oncogene expression by novel deoxyribozymes (DNAzymes).

Deoxyribozymes, or DNA enzymes (DNAzymes), are novel nucleic acids that have the ability to bind to specific sequences of RNA, and to cleave the target site catalytically. DNAzymes are smaller and more efficient enzymatically than ribozymes (RZs), which are catalytic nucleic acids synthesized from ribonucleotides. We have designed three DNAzymes that specifically target the two variants of the p210 bcr-abl gene (splice 1, b3a2; splice 2, b2a2) and the p190 variant (ela2). The cleavage sites for these DNAzymes are located 5 nucleotides (nt) 5' from the fusion site for b3a2, and only 1 nt 5' from the fusion sites for b2a2 and e1a2. We have shown in cell-free in vitro cleavage assays that these DNAzymes efficiently cleave their respective substrates. Mutated DNAzymes, in which only one critical base has been altered, do not cleave these targets. We have used a serum-resistant cytofectin (GS 2888; Gilead) to transfect the DNAzymes into target K562 cells, which express p210bcr-abl. In short-term transfection assays, the DNAzymes specifically inhibited p210bcr-abl protein expression by K562 cells by about 40%, and inhibited cell growth by more than 50% in a 6-day liquid culture assay. We have also transfected freshly isolated CD34+ bone marrow cells from patients with CML with the DNAzymes, which specifically inhibited the growth of bcr-abl-positive CFU-Mix colonies by 53-80%. The potential advantages of anti-bcr-abl DNAzymes over RZs include the following: DNAzymes are much less expensive to synthesize; they are more resistant to serum; and the anti-b2a2 DNAzyme cleaves at a site only 1 nt away from the fusion site, whereas its hammerhead RZ counterpart cleaves this target at a site 8 nt 3' to the fusion site, well within abl exon 2. DNAzymes are novel RNA-cleaving molecules that may significantly improve our ability to inhibit bcr-abl oncogene expression in Ph-positive target cells.

Alternative Splicing↗

PubMed1999

DNA immunisation with Onchocerca volvulus chitinase induces partial protection against challenge infection with L3 larvae in mice.

The parasitic nematode, Onchocerca volvulus is a major cause of blindness and dermal pathology in tropical regions. A vaccine directed to infective larvae would provide a valuable control tool alongside the current methods of chemotherapy and vector control. Previously we have described the identification of a chitinase cDNA that is expressed in a stage specific manner by O. volvulus infective third stage (L3) larvae. To evaluate its host protective potential, the complete open reading frame was cloned into the eukaryotic expression plasmid pJW4303 and used to vaccinate mice by DNA immunisation with the Accell GeneGun. The survival of challenge infective larvae was monitored using implanted micropore chambers. In the first trial, mice immunised 3 times over 4 months with 1 microg O. volvulus chitinase DNA responded with modest antibody responses dominated by IgG2a and exhibited a 36% (p=0.189, NS) reduction in parasite survival compared with challenge controls. In the second trial, an increased dose of DNA (5 microg) and more frequent immunisations (5 times over 6 months) stimulated an IgG1 dominant response and a 53% reduction in parasite survival (p=0.042). Antibodies from the vaccinated mice reacted with the cuticle of post-infective L3 larvae, implying that this may be the site of immune attack following secretion of chitinase.

Animals↗

PubMed1999

Network construction of first aid for electrical injury in the east China area of China Power.

Electrical injury is an area of burn medicine that requires specialized treatment. Injury rates have reached 6.56% in 1990, compared to only 1% prior to 1980. In recent years, the morbidity has steadily increased due to the rapid development of the electrical power industry and the popularization of electrical installations. Electrical accidents cause severe damage to muscle and tissue, which makes treatment of these accident patients quite challenging. Therefore, it is very important to promote the widespread use of a first aid network within the electrical power system while strengthening safety measures within the industry to reduce morbidity and mortality among the electrically injured. To date, similar networks have been established in East China, Central China, North China, and Shandong within the six major electrical power industries. We hope to minimize the injury of workers through appropriate supervision, improved safety measures, and improved safeguarding of equipment.

Accidents, Occupational↗

PubMed1999

A clinical analysis of 836 cases with electric injury.

Eight hundred thirty-six patients with electric injury were admitted to Shanghai Power Hospital from 1972 to 1998. The majority of electric injury patients were young or middle-aged industrial workers from both cities and rural areas. These patients were classified into three categories depending on the type of electric injury: (1) electric shock; (2) electric contact burn injury; (3) electric arc burn. In our study of wound management, we focused on three areas: first, the choice of operation time in electric burn injury; second, the methods of wound management on the injured extremities, especially the hands and upper limbs; third, functional site wounds that included some exposed blood vessels. Nerves and tendons were covered and repaired by various flaps. Through the analysis of 836 electric injury cases, we summarized our experience of treating electric injury with the purpose of increasing our knowledge in the area of electric injury prevention and treatment.

Accidents, Occupational↗

PubMed1999

Experience of the treatment of severe electric burns on special parts of the body.

The treatment in these eight cases with severe electric burns on special parts of the body was successful. Our experience can be summarized as follows: (1) The role of the immediate measures including resuscitation at the scene of the accident cannot be understated. If the patient presents with a complex injury such as open pneumothorax, first aid should be provided immediately and then the patient should be transferred to a specialized treatment center. (2) General conditions such as the presence of shock, water-electrolyte balance, renal function, and others should be continuously monitored. (3) Antibiotics should be suitably administered and combined with antianaerobic drugs. (4) For different wound sites, different plans of treatment, including various immediate and delayed procedures, could be appropriate. In life-threatening cases such as exposed carotid artery, perforative injury of the chest wall, spinal cord damage, and others, first-stage repair using skin flap or myocutaneous flap must be performed after early debridement. For other wound sites, such as oral area and tongue, eye socket, and penis, second-stage reconstruction may be more suitable for better cosmetic appearance and function. (5) Adequate nutritional supply and early treatment of anemia may expedite wound healing.

Accidents, Occupational↗

PubMed1999

An integrated decoupler for capillary electrophoresis with electrochemical detection: application to analysis of brain microdialysate.

An approach to capillary electrophoresis with electrochemical detection (CE-EC) suitable for determination of dopamine in 1-min brain microdialysate samples is described. The CE-EC system includes an electrochemical detection cell that permits easy, precise, and permanent alignment of a carbon fiber microelectrode with a separation capillary (30-micron i.d., 75-cm length). Amperometric detection was performed at a constant applied potential of 600 mV with respect to a Ag/AgCl reference electrode. Decoupling of the electrophoretic current from the amperometric detector was accomplished with an integrated end-column decoupler prepared by etching the capillary outlet with HF. The decoupler produces baseline noise of 50 fA, or less, in the presence of 10-20-muA current in the separation capillary. The low baseline noise affords low mass (attomoles) and low concentration (nanomolar) detection limits for dopamine and 4-methylcatechol. A peak attributable to dopamine was identified in electropherograms of brain microdialysate samples obtained from anesthetized rats. Identification of the dopamine peak was confirmed by pharmacological methods. Dopamine was readily detected in 1-min brain microdialysate samples. The dopamine concentration in 1-min brain microdialysis samples was significantly altered by drug treatments and by brief electrical stimulation of dopaminergic axons.

Animals↗

PubMed1999

Improvements in gel composition and electrophoretic conditions for broad-range mutation analysis by denaturing gradient gel electrophoresis.

Denaturing gradient gel electrophoresis (DGGE) is believed to be the most powerful pre-screening method for mutation detection currently available, being used mostly on an exon-by-exon basis. Broad-range DGGE for the analysis of multiple fragments or an entire gene is rarely applied. We and others have already shown that one or two DGGE conditions are usually sufficient to analyse an entire gene. Conditions, however, have never been profoundly tested and compared with alternative methods suggested in the literature. Trying to do so in this study, we found significant differences between the various gel systems. The optimal conditions we found for broad-range DGGE include 9% polyacrylamide for the gel, a denaturing gradient with a difference of 30-50% between the lowest and the highest concentration of denaturant, and electrophoresis in 0.5x TAE buffer at a voltage >100 V and <200 V.

Acrylic Resins↗