Avian flu: H5N1 virus outbreak in migratory waterfowl.
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Animal Migration↗
Biomedical subjects
J Wang
Publications and source records attributed to J Wang.
Defining the orientation of the tandem fusions that occurred during the evolution of Indian muntjac chromosomes by BAC mapping.
The Indian muntjac (Muntiacus muntjak vaginalis) has a karyotype of 2n=6 in the female and 7 in the male, the karyotypic evolution of which through extensive tandem fusions and several centric fusions has been well-documented by recent molecular cytogenetic studies. In an attempt to define the fusion orientations of conserved chromosomal segments and the molecular mechanisms underlying the tandem fusions, we have constructed a highly redundant (more than six times of whole genome coverage) bacterial artificial chromosome (BAC) library of Indian muntjac. The BAC library contains 124,800 clones with no chromosome bias and has an average insert DNA size of 120 kb. A total of 223 clones have been mapped by fluorescent in situ hybridization onto the chromosomes of both Indian muntjac and Chinese muntjac and a high-resolution comparative map has been established. Our mapping results demonstrate that all tandem fusions that occurred during the evolution of Indian muntjac karyotype from the acrocentric 2n=70 hypothetical ancestral karyotype are centromere-telomere (head-tail) fusions.
Animals↗
Two domains within the first putative transmembrane domain of presenilin 1 differentially influence presenilinase and gamma-secretase activity.
Presenilins (PS) are thought to contain the active site for presenilinase endoproteolysis of PS and gamma-secretase cleavage of substrates. The structural requirements for PS incorporation into the gamma-secretase enzyme complex, complex stability and maturation, and appropriate presenilinase and gamma-secretase activity are poorly understood. We used rescue assays to identify sequences in transmembrane domain one (TM1) of PS1 required to support presenilinase and gamma-secretase activities. Swap mutations identified an N-terminal TM1 domain that is important for gamma-secretase activity only and a C-terminal TM1 domain that is essential for both presenilinase and gamma-secretase activities. Exchange of residues 95-98 of PS1 (sw95-98) completely abolishes both activities while the familial Alzheimer's disease mutation V96F significantly inhibits both activities. Reversion of residue 96 back to valine in the sw95-98 mutant rescues PS function, identifying V96 as the critical residue in this region. The TM1 mutants do not bind to an aspartyl protease transition state analog gamma-secretase inhibitor, indicating a conformational change induced by the mutations that abrogates catalytic activity. TM1 mutant PS1 molecules retain the ability to interact with gamma-secretase substrates and gamma-secretase complex members, although Nicastrin stability is decreased by the presence of these mutants. gamma-Secretase complexes that contain V96F mutant PS1 molecules display a partial loss of function for gamma-secretase that alters the ratio of amyloid-beta peptide species produced, leading to the amyloid-beta peptide aggregation that causes familial Alzheimer's disease.
Amino Acid Sequence↗
Highly pathogenic H5N1 influenza virus infection in migratory birds.
H5N1 avian influenza virus (AIV) has emerged as a pathogenic entity for a variety of species, including humans, in recent years. Here we report an outbreak among migratory birds on Lake Qinghaihu, China, in May and June 2005, in which more than a thousand birds were affected. Pancreatic necrosis and abnormal neurological symptoms were the major clinical features. Sequencing of the complete genomes of four H5N1 AIV strains revealed them to be reassortants related to a peregrine falcon isolate from Hong Kong and to have known highly pathogenic characteristics. Experimental animal infections reproduced typical highly pathogenic AIV infection symptoms and pathology.
Amino Acid Sequence↗
An analysis of fishing vessel accidents.
In this paper, accident data collected from the Marine Accident Investigation Branch are presented and an analysis is carried out to determine the most common causes of accidents on fishing vessels. Discussions on fishing vessel-safety assessment and data problems are given.
Accidents, Occupational↗
Effect of human vasoactive intestinal peptide gene transfer in a murine model of Sjogren's syndrome.
BACKGROUND: Sjögren's syndrome (SS), an autoimmune exocrinopathy mainly affecting lachrymal and salivary glands, results in ocular and oral dryness (keratoconjunctivitis sicca and xerostomia). The aetiology and pathogenesis are largely unknown; currently, only palliative treatment is available. OBJECTIVE: To determine whether gene transfer of vasoactive intestinal peptide (VIP), based on its immunomodulatory properties, might be useful in the management of SS. METHODS: A recombinant serotype 2 adeno-associated virus encoding the human VIP transgene (rAAV2hVIP) was constructed and its efficacy tested in the female non-obese diabetic (NOD) mouse model for SS after retrograde instillation in submandibular glands (SMGs). 10(10) particles/gland of rAAV2hVIP or rAAV2LacZ (encoding beta-galactosidase; control vector) were administered at 8 weeks of age (before sialadenitis onset). Salivary flow rates were determined before vector delivery and at time of death (16 weeks). After death, saliva, serum, and SMGs were harvested. Salivary output, inflammatory infiltrates (focus scores), VIP protein expression, cytokine profile, and serum anti-VIP antibodies were analysed. RESULTS: rAAV2hVIP significantly improved the salivary flow, increased SMG and serum expression of VIP, and reduced SMG cytokines interleukin (IL) 2, IL10, IL12 (p70), and tumour necrosis factor alpha, and serum RANTES, compared with the control vector. No difference in focus scores or apoptotic rates was found; neutralising antibodies were not detected. CONCLUSIONS: Local delivery of rAAV2hVIP can have disease modifying and immunosuppressive effects in SMGs of the NOD mouse model of SS. The new strategy of employing VIP prophylactically may be useful for both understanding and managing the salivary component of SS.
Adenoviridae↗
Determination of levodopa methyl ester and its metabolites in rat serum by CZE with amperometric detection.
A reliable and reproducible method, capillary zone electrophoresis with amperometric detection (CZE-AD), has been developed for separation and quantification of levodopa methyl ester (LDME) and its biotransformation products levodopa (L-DOPA) and dopamine (DA) in rat serum. A carbon-disk electrode was used as working electrode. The optimum conditions for CZE detection were 50 mmol L(-1) phosphate solution at pH 7.0 as running buffer, 17 kV as separation voltage, 1.0 V (vs Ag/AgCl, 3.0 mol L(-1)) as detection potential, and sample injection for 8 s at 17 kV. The linear ranges were from 2.4 x 10(-2) to 2.2 microg mL(-1) for LDME, 2.9 x 10(-1) to 49.5 microg mL(-1) for L-DOPA, and 1.4 x 10(-2) to 1.5 microg mL(-1) for DA with correlation coefficients of 0.9997, 0.9994, and 0.9999, respectively. The detection limits for LDME, L-DOPA, and DA were 14.6, 98.0, and 9.7 ng mL(-1), respectively. Recoveries were 80.3% for LDME, 93.5% for L-DOPA, and 86.5% for DA. This method was applied to serum samples after intravenous injection of LDME and L-DOPA to rats.
Animals↗
Mechanical force activates eIF-2alpha phospho-kinases in fibroblast.
Mechanical forces can induce differentiation of fibroblasts into myofibroblasts, a process which requires activation of the MAP kinase p38. Currently, the identification of other phospho-kinases involved in myofibroblast differentiation has not been explored. We applied static tensile forces to rat cardiac fibroblasts via collagen-coated magnetite beads and examined activation of protein phospho-kinases by the Kinexus phospho-antibody screening system. Of 75 candidate protein kinases screened, 39 were detected and, of these, 31 phospho-kinases were analyzed. Following force application, 12 out of 31 phospho-kinases exhibited increases of phosphorylation including PKR (>4-fold), MKK3 (3-fold), MKK6 ( approximately 2-fold), and p38 ( approximately 2-fold). In several types of mechanically sensitive, contractile fibroblasts including rat cardiac, human gingival, and Rat-2 fibroblasts, tensile forces increased eIF-2alpha phosphorylation, a downstream effector of PKR. We conclude that phospho-antibody screening is an efficient method for discovery of novel mechanical force-induced phospho-kinases and force can activate eIF-2alpha phospho-kinases in fibroblasts.
Animals↗
Postsynaptic IP3 receptor-mediated Ca2+ release modulates synaptic transmission in hippocampal neurons.
Ca(2+)-dependent mechanisms are important in regulating synaptic transmission. The results herein indicate that whole-cell perfusion of inositol 1,4,5-trisphosphate receptor (IP(3)R) agonists greatly enhanced excitatory postsynaptic current (EPSC) amplitudes in postsynaptic hippocampal CA1 neurons. IP(3)R agonist-mediated increases in synaptic transmission changed during development and paralleled age-dependent increases in hippocampal type-1 IP(3)Rs. IP(3)R agonist-mediated increases in EPSC amplitudes were inhibited by postsynaptic perfusion of inhibitors of Ca(2+)/calmodulin, PKC and Ca(2+)/calmodulin-dependent protein kinase II. Postsynaptic perfusion of inhibitors of smooth endoplasmic reticulum (SER) Ca(2+)-ATPases, which deplete intracellular Ca(2+) stores, also enhanced EPSC amplitudes. Postsynaptic perfusion of the IP(3)R agonist adenophostin (AdA) during subthreshold stimulation appeared to convert silent to active synapses; synaptic transmission at these active synapses was completely blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Postsynaptic IP(3)R-mediated Ca(2+) release also produced a significant increase in spontaneous EPSC frequency. These results indicate that Ca(2+) release from intracellular stores play a key role in regulating the function of postsynaptic AMPARs.
2-Amino-5-phosphonovalerate↗
Expression of Catenin family members CTNNA1, CTNNA2, CTNNB1 and JUP in the primate prefrontal cortex and hippocampus.
Members of the catenin family of proteins are thought to play a major role in the folding and lamination of the cerebral cortex. We have used in situ hybridization to determine the cellular expression patterns of four members of this family, Alpha-E-, Alpha-N-, Beta-, and Gamma-catenins (CTNNA1, CTNNA2, CTNNB1, and JUP respectively) in the adult primate dorsolateral prefrontal cortex (DLPFC) and hippocampus. CTNNA2, CTNNB1, and JUP mRNAs were detected in all layers of the DLPFC and in all neuronal subregions of the hippocampal formation, however CTNNA1 mRNA, coding for an 'epithelial' specific catenin, was not detected in any region of the cortex or hippocampus. CTNNA2, a 'neuronal-specific' catenin, and CTNNB1 mRNAs were abundant in both DLPFC and hippocampus, with a distinct neuronal localization. CTNNA2 mRNA was concentrated in both granular/stellate cells and large pyramidal cell bodies, while CTNNB1 expression was more strongly associated with granular cell bodies throughout the DLPFC, with expression in pyramidal cells confined mainly to cortical Layers III and VI. CTNNA2 and CTNNB1 mRNAs were also abundant in the granule cells of the dentate gyrus and pyramidal cells of Ammon's horn, apparently co-expressed in the same neurons. JUP mRNA was rather diffusely localized in the DLPFC without the distinct laminar patterns seen for CTNNA2 and CTNNB1 but was distinctly localized in the granule cells of the dentate gyrus and pyramidal cells of Ammon's horn. These studies demonstrate a distinct neuronal pattern of gene expression for catenin family members in primate brain structures characterized by high degrees of folding and strong lamination. The high level expression of these transcripts supports the notion of a major role for catenins even in the adult brain. Such an understanding is also important in view of the multiple interactions that catenins have with many other proteins in the adult and ageing brain. This may also have implications for understanding the pathogenesis of neurodegenerative diseases such as Alzheimer's disease, as well as emerging neuronal stem cell therapies.
Animals↗
The detection of DNA deamination by electrocatalysis at DNA-modified electrodes.
The method of electrocatalysis based on using a methylene blue (MB) as an electrochemical indicator and ferricyanide ions [Fe(CN)6]3- as an electron acceptor was applied in screening DNA for lesions caused by deamination of nucleobases. The damaged DNA was modeled by short 18-mer oligonucleotides containing the different number of mismatched target bases (uracil instead of cytosine residues). The hybridization capacity of these oligomers with complementary probes (immobilized on gold electrodes or free) was investigated by both electrochemical methods and UV spectroscopy. We have shown that the amplitude of the reduction signal corresponding to ferricyanide ions considerably increases in the presence of MB. This electrocatalytic effect allowed us to detect the changes in electrochemical properties of DNA caused by dU.dG mismatches. Using differential pulse voltammetry and cyclic voltammetry, we showed that the electron transport from the electrode through the double-stranded DNA to MB and then to ferricyanide ions is suppressed by the mismatches in duplex structure. According to UV-monitored melting data, single or multiple wobble dU.dG base pairs destabilize 18-mer DNA duplex by 9-27 degrees C.
Catalysis↗
Comparison of biological activity of recombinant woodchuck interferon gamma and tumor necrosis factor alpha produced in baculovirus and Escherichia coli expression systems.
The full-length cDNAs of recombinant woodchuck interferon gamma (rwIFN gamma) and woodchuck tumor necrosis factor alpha (rwTNF alpha) were cloned into baculovirus transfer vectors and expressed in insect Sf9 cells. The recombinant proteins secreted by the insect cells, bac-rwIFN gamma and bac-rwTNF alpha, were found to be functionally competent. Their biological activities were compared to those of rwIFN gamma and rwTNF alpha produced in the Escherichia coli (E. coli) expression system. The bac-rwIFN gamma demonstrated a 4.5-fold greater protective activity against encephalomyocarditis virus-induced cytolysis of woodchuck hepatocytes and that of class I MHC antigen presentation on the hepatocytes than rwIFN gamma derived from E. coli. The bac-rwTNF alpha was cytotoxic towards murine fibroblasts and able to upregulate class I MHC antigen display and these effects were about 18-fold greater than those triggered by rwTNF alpha from E. coli at a comparable protein level. In addition, the antiviral activity of bac-rwIFN gamma was inhibited by anti-wIFN gamma antibodies and the cytotoxicity of bac-rwTNF alpha neutralized by cross-reactive antibodies to murine TNF alpha. The study showed that the expression of rwIFN gamma and rwTNF alpha in the baculovirus system generated biologically active cytokines whose potency was considerably greater than those produced in E. coli.
Animals↗
Palatal and nasal necrosis resulting from cocaine misuse.
The potential social and economic harm caused by cocaine addiction is well known. The wider health risks and potential nasal complications of septal perforation and nasal collapse are also recognised. We report a case of oro-nasal fistula secondary to cocaine misuse and discuss the aetiology, management and potential methods of repair.
Administration, Inhalation↗
Spatially localized self-injection of electrons in a self-modulated laser-wakefield accelerator by using a laser-induced transient density ramp.
By using a laser-induced transient density ramp, we demonstrate self-injection of electrons in a self-modulated laser-wakefield accelerator with spatial localization. The number of injected electrons reaches 1.7 x 10(8). The transient density ramp is produced by a prepulse propagating transversely to drill a density depression channel via ionization and expansion. The same mechanism of injection with comparable efficiency is also demonstrated with a transverse plasma waveguide driven by Coulomb explosion.
Journal Article↗
A simple and convenient route to prepare poly(vinylidene fluoride trifluoroethylene) copolymer nanowires and nanotubes.
Poly(vinylidene fluoride trifluoroethylene) copolymer nanowires and nanotubes have been prepared for the first time via a high temperature (</=260 degrees C) vacuum infiltration method, which is a simple and convenient route for fabricating polymer nanowires and nanotubes when polymers, instead of monomers, are used as the starting materials.
Journal Article↗
Adsorption dynamics of CO2 on Zn-ZnO(0001): a molecular beam study.
Presented are initial S(0) and coverage Theta dependent, S(Theta), adsorption probability measurements, respectively, of CO(2) adsorption on the polar Zn-terminated surface of ZnO, parametric in the impact energy E(i), the surface temperature T(s), the impact angle alpha(i), varied along the [001] azimuth, the CO(2) flux, and the density of defects, chi(Ar(+)), as varied by rare gas ion sputtering. S(0) decreases linearly from 0.72 to 0.25 within E(i)=0.12-1.33 eV and is independent of T(s). Above E(i)=0.56 eV, S(0) decreases by approximately 0.2 with increasing alpha(i). The shape of S(Theta) curves is consistent with precursor-mediated adsorption (Kisliuk shape, i.e., S approximately const) for low E(i); above E(i)=0.56 eV, however, a turnover to adsorbate-assisted adsorption (S increases with Theta) has been observed. The initial slope of S(Theta) curves decreases thereby with increasing alpha(i), chi(Ar(+)), and T(s), i.e., the adsorbate-assisted adsorption is most distinct for normal impact on the pristine surface at low T(s) and is independent of the CO(2) flux. The S(Theta) curves have been parametrized by analytic precursor models and Monte Carlo simulations have been conducted as well. The temperature dependence of the saturation coverage shows two structures which could be assigned to adsorption on pristine and intrinsic defect sites, respectively, in agreement with a prior thermal desorption spectroscopy study. The heat of adsorption E(d) for the pristine sites amounts to 34.0-5.4Theta, whereas for adsorption on the intrinsic defect sites E(d) of approximately 43.6 kJ/mol could be estimated. Thus, a kinetic structure-activity relationship was present.
Journal Article↗
Perinucleolar compartment prevalence has an independent prognostic value for breast cancer.
The perinucleolar compartment (PNC) is a multicomponent nuclear structure enriched with RNAs transcribed by RNA pol III and RNA binding proteins. Studies in cultured cells showed an association between PNC and transformed phenotype. To evaluate the relationship between structure and malignancy in vivo, we examined PNC prevalence (the percentage of cells containing at least one PNC) in normal and cancerous paraffin-embedded breast tissues using immunohistochemistry against a PNC-associated protein. Five hundred nuclei in the most active area of each sample were scored for PNC prevalence. The results show that PNC prevalence significantly correlates with the progression of breast cancer (by the criteria of staging). PNC prevalence in primary tumors, lymph nodes, and distant metastases shows a stepwise increase from a median of 23% in primary tumors to approximately 100% in distant metastases. In addition, univariate and multivariate (controlling for tumor size and grade) analyses show that early-stage patients with invasive ductal carcinomas containing a higher PNC prevalence have a significantly poorer prognosis. These findings link PNC prevalence with the progression of breast cancer in vivo and suggest that PNC-containing cells have metastatic advantages. These findings also show the potential of PNC prevalence as a prognostic marker for breast cancer.
Aged↗
[In vitro evidence for pancreatic lineage: Ngn3 positive cells are endocrine progenitors derived from cultured islets].
OBJECTIVE: Further studies have been conducted to evaluate the roles of Ngn3 in adult islet maintenance and renewal. METHODS: Islets were isolated from 6 - 8 week old male C57BL/6 mice. After common bile duct cannulation, the pancreas was resected and digested in collagenase V (2.5 mg/ml). Islets were then handpicked and 10 - 12 islets were plated in 60 mm culture dish and cultivated with RPMI-1640, which contained 12.5 mmol/L HEPES, 5.2 mmol/L glucose and 2% fetal bovine serum (FBS). Islet cells were analyzed by immunocytochemistry methods for A6, insulin, glucagon, nestin, Ngn3 and 5-bromo-2'-deoxy-uridine (BrdU). RESULTS: The results of these studies indicated that less than 15 percent of proliferated islet cells were Ngn3 expressing cells, in which about one third of the Ngn3 positive cells co-expressed A6. The existence of Ngn3 in cultured islet cells is consistent with the results from other's findings both in embryogenesis and adult islet studies. A significant finding of our study is that the existence of A6 and Ngn3 co-expressing cells in the cultured islet. A6 is a marker for identifying bile duct epithelial cell oriented hepatic progenitor cells. Islet-derived A6 cells are possibly born in the adult pancreatic duct and migrate into islets. A6 cells co-express Ngn3 when these cells commit to endocrine lineage within the islets. More interestingly, islet-derived A6 positive cells have the potential to transdifferentiate into hepatic cells. CONCLUSION: The presence of Ngn3(+) and A6(+) cells in the cultured islets suggests that the four established islet cell types arise from a common endocrine lineage residing within the adult islets. A6 and Ngn3 are useful markers for understanding intra-islet adult stem cell lineages in our future studies. This approach may allow for significant advances in understanding the IPC proliferation and differentiation, and open the possibility of using intra-islet adult stem cells for diabetes treatment.
Animals↗