Biomedical subjects

Wei He

Publications and source records attributed to Wei He.

At least 109 records · Page 6Linked to original sources

PubMed2005

[Application of high frequency component in classification of different mental tasks].

Electroencephalogram (EEG) signals of different mental tasks were preprocessed using Independent Component Analysis (ICA). Auto-Regressive (AR) model was used to extract the feature, and Back-Propagation (BP) network as the classifier. When features were extracted from 20-100 Hz high frequency range, the classification accuracy was the same as that taken from the whole frequency range and was more higher than the result of 2-35 Hz normal EEG rhythm. The explanation of this phenomenon is: brain displays different rhythm assimilation during different mental task under the effect of 60 Hz power frequency, so the high frequency components of EEG include more mental modulated information which is useful for improving the classification accuracy. The result presents a new evidence for the brain rhythm assimilation phenomenon and gives a novel feature extraction method for realizing high accuracy real-time BCI based on mental task.

Brain↗

PubMed2005

[Development of an automatic ultrasonic cleaning machine for surgical instruments].

The automatic cleaning machine we have developed, adopts a SCM system in automatic cleaning. The machine has five functions: ultrasonic cleaning, cold or hot water spraying, drying and greasing. The clinical applications show that the machine with a good effectiveness is suitable for the cleaning of many surgical instruments. It also raises working efficiency, cuts down on the cost of repair and maintenance and reduces the injury and infection to nurses caused by manual cleaning, satisfying the needs of clinical applications.

Automation↗

PubMed2004

Deep-UV Raman spectrometer tunable between 193 and 205 nm for structural characterization of proteins.

A new deep-UV Raman spectrometer utilizing a laser source tunable between 193 and 205 nm has been designed, built, and characterized. Only selected wavelengths from this range have previously been accessible, by Raman shifting of the second, third, and fourth harmonics of the Nd:YAG fundamental in hydrogen. The apparatus was demonstrated to be a useful tool for characterizing hen egg white lysozyme structural rearrangements at various stages of fibril formation. High-quality deep-UV resonance Raman spectra were obtained for both a protein solution and a highly-scattering gelatinous phase formed by fibrillogenic species. In addition to amide bands, strong contribution of nu(12) and ring-C phenylalanine vibrational modes was observed at excitation wavelengths below 200 nm. Remarkably, the Raman cross-section of these modes revealed dramatic change of lysozyme in response to heat denaturation and fibril formation. These results indicate that phenylalanine could serve as a new deep-UV Raman probe of protein structure.

Molecular Probes↗

PubMed2004

The protective effect of a Schistosoma japonicum Chinese strain 23 kDa plasmid DNA vaccine in pigs is enhanced with IL-12.

The schistosome integral membrane protein Sm/Sj23 was initially shown to induce protection in mice as a synthetic peptide vaccine and further, as a plasmid DNA vaccine to induce protection in mice, sheep and water buffalo. In this study we asked if we could induce protection against challenge infection in pigs against Schistosoma japonicum by vaccinating them with a plasmid DNA vaccine encoding the S. japonicum Chinese strain 23 kDa membrane protein. Further, we asked if we could enhance protective efficacy of this vaccine by the addition of IL-12. We compared vaccination with SjC23 plasmid DNA alone or with IL-12 plasmid DNA in pigs. Pigs were immunized three times at three weekly intervals. Thirty Chinese Songjang native pigs were divided into three groups. In group A, each pig was immunized with 500 microg of SjC23 plasmid DNA by intramuscular (i.m.) injection in both buttocks. In group B each pig was immunized with 500 microg of SjC23 plasmid DNA, and 500 microg of each of pcDNA3.1-p35 and 500 microg of pcDNA3.1-p40 DNA by i.m. injection. In group C each pig was immunized with 500 microg of pcDNA3.1 as the control. Thirty days post-vaccination, pigs were challenged with S. japonicum cercariae and adult and egg burdens and granuloma size determined 45 days post-challenge. The results showed that worm reduction rates in SjC23 group compared with control group were 29.2% and in the SjC23 + IL-12 group reduced 58.6%. Similarly the female worm reduction rates were 50.8 and 58.8%, the hepatic egg reduction rates were 48.2 and 56.4%, and the mean square measure reduction rates of hepatic egg granulomas were 48.6 and 44.4%, the mean diameter reduction rates of granulomas were 27.6 and 22.8% in pigs vaccinated with SjC23 or SjC23 + IL-12 compared to plasmid vaccinated pigs, respectively. Analysis of sera from pigs vaccinated with SjC23 showed that 4 of 10 pigs had anti-Sj23 antibody responses; with 5 of 10 pigs positive for anti-Sj23 in the SjC23+IL-12 group. These results suggest that vaccination with Sj23 DNA vaccine induces not only a significant reduction in worm and egg burdens, but also significantly reduces the size of egg granulomas, thus is also anti-pathology.

Animals↗

PubMed2004

Rationale, design, and synthesis of novel phenyl imidazoles as opioid receptor agonists for gastrointestinal disorders.

A small series of novel, imidazoles 4 have been prepared that exhibit very good binding affinities for the delta and mu opioid receptors (ORs), as well as demonstrate potent agonist functional activity at the delta OR. Representative imidazole 4a (K(i) delta = 0.9 nM; K(i) mu = 55 nM; K(i) kappa = 124 nM; EC(50) delta =13-25 nM) was further profiled for OR related in vivo effects. Compound 4a reduced gastrointestinal (GI) propulsive motility in a dose-dependent and naloxone-reversible manner, based on the results of the mouse glass bead expulsion test (3, 5, and 10 mg/kg, ip) and the mouse fecal pellet output test (1 and 3 mg/kg, ip). Compound 4a showed no analgesic activity as measured by the mouse abdominal irritant test (MAIT) when dosed at 100 mg/kg, sc, but did show significant MAIT activity at doses of both 10 microg (40% inhibition) and 100 microg (100% inhibition) when dosed intracerebroventricularly (icv). Taken together, these in vivo results suggest that 4a acts peripherally when dosed systemically, and that these prototypical compounds may prove promising as medicinal leads for GI indications.

Abdominal Muscles↗

PubMed2004

Umami taste responses are mediated by alpha-transducin and alpha-gustducin.

The sense of taste comprises at least five distinct qualities: sweet, bitter, sour, salty, and umami, the taste of glutamate. For bitter, sweet, and umami compounds, taste signaling is initiated by binding of tastants to G-protein-coupled receptors in specialized epithelial cells located in the taste buds, leading to the activation of signal transduction cascades. Alpha-gustducin, a taste cell-expressed G-protein alpha subunit closely related to the alpha-transducins, is a key mediator of sweet and bitter tastes. Alpha-gustducin knock-out (KO) mice have greatly diminished, but not entirely abolished, responses to many bitter and sweet compounds. We set out to determine whether alpha-gustducin also mediates umami taste and whether rod alpha-transducin (alpha(t-rod)), which is also expressed in taste receptor cells, plays a role in any of the taste responses that remain in alpha-gustducin KO mice. Behavioral tests and taste nerve recordings of single and double KO mice lacking alpha-gustducin and/or alpha(t-rod) confirmed the involvement of alpha-gustducin in bitter (quinine and denatonium) and sweet (sucrose and SC45647) taste and demonstrated the involvement of alpha-gustducin in umami [monosodium glutamate (MSG), monopotassium glutamate (MPG), and inosine monophosphate (IMP)] taste as well. We found that alpha(t-rod) played no role in taste responses to the salty, bitter, and sweet compounds tested or to IMP but was involved in the umami taste of MSG and MPG. Umami detection involving alpha-gustducin and alpha(t-rod) occurs in anteriorly placed taste buds, however taste cells at the back of the tongue respond to umami compounds independently of these two G-protein subunits.

Animals↗

PubMed2004

Inhibition of mouse hepatocyte apoptosis via anti-Fas ribozyme.

AIM: To investigate the effects of anti-Fas ribozyme on Fas expression and apoptosis in primary cultured mouse hepatocytes. METHODS: Mouse hepatocytes were isolated by using collagenase irrigation. A hammerhead ribozyme targeting the Fas mRNA was constructed, and transfected into mouse hepatocytes via Effectene. Then Fas expression in mouse hepatocytes was detected by RT-PCR and western blotting. After being treated with anti-Fas antibody (JO2), hepatocytes viability was measured with MTT assay. Caspase-3 proteolytic activity was detected, and cell apoptosis was measured according to Annexin V-FITC apoptosis detection kit. RESULTS: Fas expressed in primary mouse hepatocytes. Fas expression in hepatocytes transfected with anti-Fas ribozyme was decreased remarkably and correlated with the resistance to Fas-mediated apoptosis as determined by flow cytometry and caspase-3 proteolytic activity. CONCLUSION: Anti-Fas ribozyme can remarkably decrease the Fas expression in mouse hepatocytes, thus inhibit Fas-mediated apoptosis in hepatocytes. It is suggested that anti-Fas ribozyme could significantly increase the resistance of transplanted hepatocytes to apoptosis and improve the survival of transplanted hepatocytes.

Animals↗

PubMed2004

Source identification of PM10, collected at a heavy-traffic roadside, by analyzing individual particles using synchrotron radiation.

Synchrotron radiation microbeam X-ray fluorescence (micro-SXRF) was used to analyze individual aerosol particles collected at a height of 2 m above a heavy-traffic roadside in a heavy-industrial area of Shanghai. A pattern recognition technique, which took micro-SXRF spectra of single aerosol particles as its fingerprint, was used to identify the origins of the particles. The particles collected from the environmental monitoring site are mainly from metallurgic industry (26%), unleaded gasoline automobile exhaust (15%), coal combustion (10%), cement dust (10%) and motorcycle exhaust (8%).

Aerosols↗

PubMed2004

Efficient catalysis of Nazarov cyclization using a cationic iridium complex possessing adjacent labile coordination sites.

The dicationic Ir(III) complex [IrMe(CO)(dppe)(DIB)](BARF)2 having adjacent labile sites has been found to be a very effective catalyst for promoting the Nazarov cyclization of aryl vinyl and divinyl ketones. Spectroscopic evidence for a substate-catalyst complex before cyclization is presented. The efficiency of the cyclization is attributed to the electrophilicity of the Ir(III) complex and substrate activation via chelation.

Journal Article↗

PubMed2004

Endothelial induction of fgl2 contributes to thrombosis during acute vascular xenograft rejection.

Thrombosis is a prominent feature of acute vascular rejection (AVR), the current barrier to survival of pig-to-primate xenografts. Fibrinogen-like protein 2 (fgl2/fibroleukin) is an inducible prothrombinase that plays an important role in the pathogenesis of fibrin deposition during viral hepatitis and cytokine-induced fetal loss. We hypothesized that induction of fgl2 on the vascular endothelium of xenografts contributes to thrombosis associated with AVR. We first examined fgl2 as a source of procoagulant activity in the pig-to-primate combination. The porcine fgl2 (pfgl2) was cloned and its chromosomal locus was identified. Recombinant pfgl2 protein expressed in vitro was detected on the cell surface and generated thrombin from human prothrombin. Studies of pig-to-baboon kidney xenografts undergoing AVR in vivo revealed induction of pfgl2 expression on graft vascular endothelial cells (ECs). Cultured porcine ECs activated by human TNF-alpha in vitro demonstrated induction of pfgl2 expression and enhanced activation of human prothrombin. The availability of gene-targeted fgl2-deficient mice allowed the contribution of fgl2 to the pathogenesis of AVR to be directly examined in vivo. Hearts heterotopically transplanted from fgl2(+/+) and fgl2(+/-) mice into Lewis rats developed AVR with intravascular thrombosis associated with induction of fgl2 in graft vascular ECs. In contrast, xenografts from fgl2(-/-) mice were devoid of thrombosis. These observations collectively suggest that induction of fgl2 on the vascular endothelium plays a role in the pathogenesis of AVR-associated thrombosis. Manipulation of fgl2, in combination with other interventions, may yield novel strategies by which to overcome AVR and extend xenograft survival.

Acute Disease↗

PubMed2004

Presynaptic inactivation of action potentials and postsynaptic inhibition of GABAA currents contribute to KA-induced disinhibition in CA1 pyramidal neurons.

Kainate-type glutamate ionotropic receptors (KAR) mediate either depression or potentiation of inhibitory transmission. The mechanisms underlying the depressant effect of KAR agonists have been controversial. Under dual patch-clamp recording techniques in synaptically coupled pairs of CA1 interneurons and pyramidal neurons in hippocampal slices, micromolar concentrations of KAR agonists, kainic acid (KA, 10 microM) and ATPA (10 microM), induced inactivation of action potentials (APs) in 58 and 50% of presynaptic interneurons, respectively. Inactivation of interneuronal APs might have significantly contributed to KA-induced decreases in evoked inhibitory postsynaptic currents (eIPSCs) that are obtained by stimulating the stratum radiatum. With controlled interneuronal APs, KAR agonists induced a decrease in the potency (mean amplitude of successful events) and mean amplitude (including failures) of unitary inhibitory postsynaptic currents (uIPSCs) without significantly changing the success rate (P(s)) at perisomatic high-P(s) synapses. In contrast, KAR agonists induced a decrease in both the P(s) and potency of uIPSCs at dendritic high-P(s) synapses. KAR agonists induced an inhibition of GABA(A) currents by activating postsynaptic KARs in pyramidal neurons; this was more prominent at dendrites than at soma. Both the exogenous GABA-induced current and the amplitude of miniature IPSCs (mIPSCs) were attenuated by KAR agonists. Thus the postsynaptic KAR-mediated inhibition of GABA(A) currents may contribute to the KAR agonist-induced decrease in the potency of uIPSCs and KA-induced disinhibition.

Action Potentials↗

PubMed2004

Aza-bicyclic amino acid sulfonamides as alpha(4)beta(1)/alpha(4)beta(7) integrin antagonists.

The design, synthesis, and biological activity of novel alpha(4)beta(1) and alpha(4)beta(7) integrin antagonists, containing a bridged azabicyclic nucleus, are reported. Conformational analysis of targets containing an azabicyclo[2.2.2]octane carboxylic acid and known integrin antagonists indicated that this azabicycle would be a suitable molecular scaffold. Variation of substituents on the pendant arylsulfonamide and phenylalanine groups resulted in potent alpha(4)beta(1)-selective and dual alpha(4)beta(1)/alpha(4)beta(7) antagonists. Potent compounds 11i, 11h, and 14 were effective in the antigen-sensitized sheep model of asthma.

Amino Acids↗

PubMed2004

Significant changes of peripheral T lymphocyte subsets in patients with severe acute respiratory syndrome.

This report demonstrates that a rapid decrease of peripheral T cell subsets is a unique characteristic in patients with SARS during acute infection, although total white blood cell counts, red blood cell counts, and platelet counts remain relatively normal. In recovering patients, a rapid and dramatic restoration of peripheral T cell subsets was seen in the periphery. Although the underlying mechanism of the acute decrease of peripheral T cell subsets observed in patients with SARS during the acute stage remains unknown, this clinical characteristic can facilitate an earlier and more accurate diagnosis of SARS.

Antigens, CD↗

PubMed2004

Lithography application of a novel photoresist for patterning of cells.

Photolithography is the current workhorse for the microelectronic industry. It has been used extensively for the creation of patterns on two-dimensional surfaces. Various research groups have studied the use of photolithography to pattern surfaces for the alignment of cells. So far, these applications have been limited due to the use of organic solvents in the pattern developing process, which can denature biomacromolecules that would be attached to the material. To address this problem, a novel bioactive photoresist (bioresist) based on the copolymer of methyl methacrylate and 3-(t-butoxycarbonyl)-N-vinyl-2-pyrrolidone (MMA:TBNVP) was prepared and in vitro fibroblast cell growth on this resist was studied. Results demonstrated that the resist is non-adhesive to the fibroblast cells. By deprotecting the t-BOC groups into carboxyl groups (MMA:D-TBNVP), the material became cell adhesive. Furthermore, cells were able to proliferate on the MMA:D-TBNVP surface. By culturing cells on the MMA:D-TBNVP surface in serum versus serum-free medium, we reached the conclusion that the chemistry of the deprotected copolymer indirectly promoted cell attachment through its absorbance of serum proteins on the material. Patterns of 25 microm x 25 microm lines were obtained by chemically manipulating the surface of the photoresist using UV lithography without any solvent development. Fibroblast cells were observed to align on the patterned surface. This resist could be a suitable candidate to improve the application of conventional lithography in direct protein patterning for the guided growth of cells.

Animals↗

PubMed2004

UL16 binding proteins.

According to present concepts, innate immunity plays an important role in tumor surveillance and immune modulation. The state of NK cells depends on the balance between inhibitory and activating signals from corresponding receptors. As one of the activating receptors, NKG2D recognises some self ligands such as MICA/B in human and Rae1 in mice, which is dissimilar to those toll-like receptors that recognise some pathogen-derived ligands. NKG2D is expressed not only on NK cells, but on gammadelta T cells, CD8+ alphabeta T cells in normal individuals and CD4+ alphabeta T cells in rheumatoid arthritis patients and plays a different role on respective cells. Whereas NKG2D can only function as a costimulatory receptor on CD8+ alphabeta T cells under the domination of alphabeta TCR in spite of a deficiency of costimulatory molecule CD28, NKG2D can directly activate NK cells even in the presence of inhibitory signals from MHC-I and corresponding receptor complexes. Experiments in mice have identified that alternative splicing produces two distinct NKG2D polypeptides that associate differentially with the DAP10 and DAP12 signaling subunits and that differential expression of these isoforms and of signaling proteins determines whether NKG2D only functions as a costimulatory receptor in the adaptive immune system (CD8+ T cells) or as both a primary recognition unit and a costimulatory receptor in the innate immune system (natural killer cells and macrophages). This review summarizes the research achievements in a new ligand family (UL16 binding proteins) of NKG2D in human and shows the possible prospects of ULBP function and application.

Animals↗

PubMed2004

Melanin pigment formation and increased UV resistance in Bacillus thuringiensis following high temperature induction.

The pigment melanin is well known to protect against the damaging effects of UV radiation. In this study, we show that thirty-five of thirty-seven tested Bacillus thuringiensis strains possess the potential to produce melanin in the presence of L-tyrosin at elevated temperature (42 degrees C). These findings offer a method of protecting insecticidal toxins produced by B. thuringiensis from UV degredation and may therefore have important applications in the field of crop protection. Toxicity assays on Heliothis armigera suggested that the insecticidal activity of B. thuringiensis that produced melanin was significantly higher after UV irradiation than when melanin was not produced.

Animals↗

PubMed2004

Inhibition of Fas-mediated apoptosis in Yac-1 cell via Anti-Fas ribozyme.

To detect a new and more effective way against apoptosis mouse lymphomatic cell line Yac-1 in which fas gene was expressed highly was used as a model for studying the effects of anti-Fas ribozyme on Fas-mediated apoptosis. A hammerhead ribozyme gene targeting the fas mRNA was synthesized and its in vitro transcription vector was constructed, which was transfected into Yac-1 cells using electroporation. Rz596 expression was detected using RT-PCR, and Fas expression in Yac-1 cells was detected using RT-PCR, Western blot and flow cytometry. After treated with anti-Fas antibody (JO2), Yac-1 cell viability was measured with MTT assay, caspase-3 proteolytic activity was detected, and cell apoptosis was measured according to annexin V apoptosis detecting kit. Anti-Fas ribozyme could cleave fas mRNA efficiently in vivo and in vitro. Fas expression in Yac-1 cells transfected with anti-Fas ribozyme was decreased remarkably and correlated with resistance to Fas-mediated apoptosis as determined by flow cytometry and caspase-3 proteolytic activity. Anti-Fas ribozyme was detected in cells transfected with pU6-RZ596 and pU6-dRZ596 and could remarkably decrease the Fas expression in Yac-1 cells, which made Yac-1 cells get rid of Fas-mediated apoptosis. Because of wide expression of fas in organs and tissues, our research was very useful for studying the inhibition of apoptosis of many organs and tissues in the future.

Animals↗

PubMed2004

The fgl2 prothrombinase/fibroleukin gene is required for lipopolysaccharide-triggered abortions and for normal mouse reproduction.

Increased fgl2 prothrombinase activity in maternal decidua and fetal trophoblasts may trigger abortions by proinflammatory cytokines induced by bacterial lipopolysaccharide (LPS) in mice and is implicated in human recurrent miscarriages and pre-eclampsia. Defining the physiological and pathological role of the fgl2/fibroleukin gene required an fgl2-knockout mouse and data on normal pattern of fgl2 expression during pregnancy. Expression of fgl2 protein was determined by immunostaining with specific antibody. Fgl2 knockout mice were generated and typed by PCR for presence of the altered gene. Immunostaining of timed CBAxDBA/2 mouse matings in a low-abortion-rate colony showed a distinct pattern of development of fgl2 protein expression in maternal decidua, and in embryonic tissues in early pregnancy. Outbred (mixed background) heterozygous fgl2 +/-x+/- matings with a similar low abortion rate showed selective occult loss of both +/- and, to a greater extent, -/- embryos prior to gestation day 11.5, in association with haemorrhage at the anti-mesometrial pole of fgl2-deficient embryo. LPS injected on day 6.5 caused classical abortions at mid-pregnancy in fgl2 +/+x+/+ matings, but not -/-x-/- matings. Physiological expression of fgl2 in fetal trophoblast may prevent occult loss in early pregnancy, along with other coagulation factors, but fgl2 expression is required for LPS to induce abortion pathology.

Abortion, Spontaneous↗