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E Wang

Publications and source records attributed to E Wang.

At least 73 records · Page 4Linked to original sources
PubMed2001

A cross-sectional study of human serum sphingolipids, diet and physiologic parameters.

Sphinganine and sphingosine, the two sphingoid base backbones of sphingolipids, are highly bioactive compounds that are of increasing interest to nutritionists because they occur in food and their metabolism can be altered by fungal toxins that contaminate some foods. Nonetheless, no studies of diet and sphinganine or sphingosine concentrations in serum have yet been reported. Here we describe a cross-sectional study of 265 residents of Linxian, People's Republic of China, which examines potential demographic, physiologic and dietary correlates of serum sphinganine and sphingosine in this population. Median concentrations of serum sphinganine and sphingosine were compared among strata for 29 different variables. For sphinganine, no significant differences were found. For sphingosine, significant differences were seen among strata of age, menstruation status, serum cholesterol, carotenoids, retinol, tocopherols, fresh and dried vegetable and fresh fruit consumption. Using multivariate linear regression with stepwise selection, we found that the significant predictors for serum sphingosine included total tocopherols, age, serum selenium and retinol, with a final R(2) = 0.22; for sphinganine, tooth loss was the sole correlate, with R(2) = 0.015. Analyses using ranked sphingolipid data or principal components analysis, to simplify the food variables, did not materially alter these results. This study represents the largest report of human serum sphingolipid concentrations to date and provides insight into potential explanatory variables that can be incorporated into future studies.

Adult↗
PubMed2001

Flexible use of high-density oligonucleotide arrays for single-nucleotide polymorphism discovery and validation.

A method for identifying and validating single nucleotide polymorphisms (SNPs) with high-density oligonucleotide arrays without the need for locus-specific polymerase chain reactions (PCR) is described in this report. Genomic DNAs were divided into subsets with complexity of ~10 Mb by restriction enzyme digestion and gel-based fragment size resolution, ligated to a common adaptor, and amplified with one primer in a single PCR reaction. As a demonstration of this approach, a total of 124 SNPs were located in 190 kb of genomic sequences distributed across the entire human genome by hybridizing to high-density variant detection arrays (VDA). A set of independent validation experiments was conducted for these SNPs employing bead-based affinity selection followed by hybridization of the affinity-selected SNP-containing fragments to the same VDA that was used to identify the SNPs. A total of 98.7% (74/75) of these SNPs were confirmed using both DNA dideoxynucleotide sequencing and the VDA methodologies. With flexible sample preparation, high-density oligonucleotide arrays can be tailored for even larger scale genome-wide SNP discovery as well as validation.

Cell Line↗
PubMed2001

Pulmonary and systemic host response to Streptococcus pneumoniae and Klebsiella pneumoniae bacteremia in normal and immunosuppressed mice.

Mortality related to bacteremic pneumonia remains high, and the role of sepsis in inflammation, pulmonary injury, and death remains unclear, mostly in leukopenic states. In the present study, the microbiology, histopathology, and host response to Streptococcus pneumoniae and Klebsiella pneumoniae infection were determined in an experimental model of bacteremia in immunocompetent and leukopenic mice. Leukocyte depletion by cyclophosphamide did not impair the early clearance of pneumococci from blood but facilitated growth in lungs. By contrast, klebsiellae rapidly grew in blood of leukopenic mice. These observations suggest that tissue-based phagocytes and circulating leukocytes, respectively, play prominent roles in S. pneumoniae and K. pneumoniae eradication. The kinetics of leukocyte recruitment in lungs during S. pneumoniae bacteremia suggested early strong inflammation in immunocompetent mice that is associated with tumor necrosis factor alpha release and histological disorders, including cell debris and surfactant in alveolar spaces. Leukocyte depletion further stimulated pulmonary capillary leakage both in S. pneumoniae and K. pneumoniae bacteremia, which seemed attributable to bacterial virulence factors. Nitric oxide production did not differ significantly among groups. Leukopenia and low platelet counts characterized the late stage of bacteremia for both strains, but only K. pneumoniae altered renal function. Understanding the pathogenesis of bacteremia will help establish beneficial therapies for both sepsis and pneumonia.

Animals↗
PubMed2001

Potential sources of the 1995 Venezuelan equine encephalitis subtype IC epidemic.

Venezuelan equine encephalitis viruses (VEEV) belonging to subtype IC have caused three (1962-1964, 1992-1993 and 1995) major equine epizootics and epidemics. Previous sequence analyses of a portion of the envelope glycoprotein gene demonstrated a high degree of conservation among isolates from the 1962-1964 and the 1995 outbreaks, as well as a 1983 interepizootic mosquito isolate from Panaquire, Venezuela. However, unlike subtype IAB VEEV that were used to prepare inactivated vaccines that probably initiated several outbreaks, subtype IC viruses have not been used for vaccine production and their conservation cannot be explained in this way. To characterize further subtype IC VEEV conservation and to evaluate potential sources of the 1995 outbreak, we sequenced the complete genomes of three isolates from the 1962-1964 outbreak, the 1983 Panaquire interepizootic isolate, and two isolates from 1995. The sequence of the Panaquire isolate, and that of virus isolated from a mouse brain antigen prepared from subtype IC strain P676 and used in the same laboratory, suggested that the Panaquire isolate represents a laboratory contaminant. Some authentic epizootic IC strains isolated 32 years apart showed a greater degree of sequence identity than did isolates from the same (1962-1964 or 1995) outbreak. If these viruses were circulating and replicating between 1964 and 1995, their rate of sequence evolution was at least 10-fold lower than that estimated during outbreaks or that of closely related enzootic VEEV strains that circulate continuously. Current understanding of alphavirus evolution is inconsistent with this conservation. This subtype IC VEEV conservation, combined with phylogenetic relationships, suggests the possibility that the 1995 outbreak was initiated by a laboratory strain.

Amino Acid Sequence↗
PubMed2001

Brefeldin A rapidly disrupts plasma membrane polarity by blocking polar sorting in common endosomes of MDCK cells.

Recent studies showing thorough intermixing of apical and basolateral endosomes have demonstrated that endocytic sorting is critical to maintaining the plasma membrane polarity of epithelial cells. Our studies of living, polarized cells show that disrupting endocytosis with brefeldin-A rapidly destroys the polarity of transferrin receptors in MDCK cells while having no effect on tight junctions. Brefeldin-A treatment induces tubulation of endosomes, but the sequential compartments and transport steps of the transcytotic pathway remain intact. Transferrin is sorted from LDL, but is then missorted from common endosomes to the apical recycling endosome, as identified by its nearly neutral pH, and association with GFP chimeras of Rabs 11a and 25. From the apical recycling endosome, transferrin is then directed to the apical plasma membrane. These data are consistent with a model in which polarized sorting of basolateral membrane proteins occurs via a brefeldin-A-sensitive process of segregation into basolateral recycling vesicles. Although disruption of polar sorting correlates with dissociation of gamma-adaptin from endosomes, gamma-adaptin does not appear to be specifically involved in sorting into recycling vesicles, as we find it associated with the transcytotic pathway, and particularly to the post-sorting transcytotic apical recycling endosome.

Adaptor Protein Complex gamma Subunits↗
PubMed2001

Sphingolipid metabolism: roles in signal transduction and disruption by fumonisins.

Sphingolipids have important roles in membrane and lipoprotein structure and in cell regulation as second messengers for growth factors, differentiation factors, cytokines, and a growing list of agonists. Bioactive sphingolipids are formed both by the turnover of complex sphingolipids and as intermediates of sphingolipid biosynthesis. Usually, the amounts are highly regulated; however, by inhibiting ceramide synthase, fumonisins block the biosynthesis of complex sphingolipids and cause sphinganine (and sometimes sphingosine) to accumulate. Where the mechanism has been studied most thoroughly, the accumulation of sphingoid bases is a primary cause of the toxicity of fumonisin B (FB). Nonetheless, the full effects of fumonisins probably involve many biochemical events. The elevations in sphingoid bases also affect the amounts of other lipids, including the 1-phosphates and N-acetyl derivatives of sphinganine. Furthermore, the aminopentol backbone of FB1 (AP1) is both an inhibitor and a substrate for ceramide synthase, and the resultant N-palmitoyl-AP1 (PAP1) is an even more potent inhibitor of ceramide synthase (presumably as a product analog). PAP1 is 10 times more toxic than FB1 or AP1 for HT-29 cells in culture, and hence may play a role in the toxicity of nixtamalized fumonisins. All these processes--the effects of fumonisins on sphingolipid metabolism, the pathways altered by perturbation of sphingolipid metabolism, and the complex cellular behaviors regulated by sphingolipids--must be borne in mind when evaluating the pathologic effects of fumonisins.

Carboxylic Acids↗
PubMed2001

T-cell-directed cancer vaccines: the melanoma model.

Significant advances in the understanding of the molecular basis for tumour/host interactions in humans have occurred in the last decade through studying patients with metastatic melanoma. This disease is characterised by its tendency to be modulated by immunologic factors. Furthermore, immunologic manipulation of the host with various systemic agents, in particular IL-2, frequently affects this natural phenomenon and can lead to complete rejection of cancer. By studying the cellular immunology occurring in patients undergoing immunotherapy, several tumour antigens (TA) and their epitopes recognised by human leukocyte antigen (HLA) class I-restricted cytotoxic T-lymphocytes (CTL) have been identified. Most of these TA are non-mutated molecules expressed by the majority of melanoma in vivo and most melanoma cell lines. In addition, unique minimal epitopic sequences play an immunodominant role in the context of specific HLA class I alleles. Since melanoma lesions from different patients often share expression of the same TA, and a minimal peptide sequence from a TA can cause immunologic changes in multiple patients, interest has grown in the development of TA-specific vaccines suitable for broad patient populations. Repeated in vitro stimulation of peripheral blood mononuclear cells (PBMC) with TA-derived epitopes can induce a high frequency of TA-reactive T-cells in melanoma patients. The same epitopes can also enhance TA-specific T-cell reactivity in vivo when administered subcutaneously in combination with Incomplete Freund's Adjuvant (IFA). Epitope-based vaccinations, however, have not shown strong clinical efficacy unless combined with IL-2 administration. Attempts to increase the efficacy of these vaccines have combined specialised antigen-presenting cells or the administration of whole TA through DNA- or RNA-based vaccines with the intention of increasing antigen presentation and processing. Save for scattered reports, however, the success of these approaches has been limited and T-cell-directed vaccination against cancer remains at a paradoxical standstill whereby anticancer immunisation can be induced but it is not sufficient, in most cases, to induce tumour regression. Using melanoma as the standard model for immunotherapy, we will review various methods of T-cell-directed vaccination, the monitoring and analysis of the resulting immune response, and several clinical trials in which cancer vaccines have successfully induced immunisation.

Antigens, Neoplasm↗
PubMed2001

T-cell-directed cancer vaccines: mechanisms of immune escape and immune tolerance.

Recent clinical trials using vaccines directed toward tumour-associated antigens (TA) have shown the increasing capacity of vaccines to cause immunologic responses. In fact, strongly reactive TA-specific cytolytic T-lymphocytes and tumour-infiltrating lymphocytes (TIL) can be identified and expanded ex vivo from patients with metastatic melanoma vaccinated with melanoma-associated antigens. Paradoxically, this strong immunological response does not correlate with clinical tumour regression. Proposed mechanisms responsible for this glaring inconsistency are numerous and varied; systemic immunosuppressive as well as local mechanistic factors are implicated. In this review we will critically evaluate the possible mechanisms that allow tumours to escape immune destruction and be tolerated by the immune system. In addition, strategies that may allow further insight into the biology of tumour rejection are discussed, in the hope of deepening the understanding of this phenomenon and enhancing its therapeutic potential.

Cancer Vaccines↗
PubMed2001

Ion-channel sensing of ferricyanide anion based on a supported bilayer lipid membrane.

Ferricyanide anion has usually been used as a marker of ion-channel sensors. In this work we first found that ferricyanide, itself, can act as a stimulus to regulate the permeability of sBLM prepared from didodecyldimethylammonium bromide (a kind of synthetic lipid) on a GC electrode. We used cyclic voltammetry and a.c. impedance to investigate this phenomenon. The interaction between sBLM and ferricyanide concerns time. Furthermore, we developed a sensor for ferricyanide anion. The ion-channel sensor is highly sensitive. It can detect ferricyanide concentration as low as 5 microM.

Anions↗
PubMed2001

Virulence and viremia characteristics of 1992 epizootic subtype IC Venezuelan equine encephalitis viruses and closely related enzootic subtype ID strains.

Following a 19-year hiatus, Venezuelan equine encephalitis (VEE) reemerged in western Venezuela in December 1992. This outbreak is important in understanding VEE emergence because phylogenetic studies imply that sympatric, enzootic, subtype ID VEE viruses mutated to generate the epizootic/epidemic. Although the 1992-1993 strains belong to subtype IC, a serotype implicated in extensive outbreaks during the 1960s and in 1995, relatively small numbers of human and equine cases occurred in 1992-1993. We, therefore, evaluated the pathogenicity of these Venezuelan enzootic ID and epizootic IC viruses to determine 1) if they exhibit phenotypes like those described previously for more distantly related enzootic and epizootic strains, and 2) if the 1992-1993 outbreak was limited by the inability of these IC viruses to exploit equines as amplification hosts. All strains were virulent in mice and guinea pigs, but were benign for cotton rats, natural hosts of enzootic viruses. However, only the IC strains produced equine disease, with mean peak viremias of 10(5) suckling mouse 50% lethal doses per mL serum, and some titers exceeding 10(7). These viremias approximate those observed previously with VEE strains isolated during more extensive epizootics, suggesting that efficient equine amplification did not limit the scope and duration of the 1992-1993 outbreak. Enzootic ID virus infection protected all horses from challenge with epizootic strain P676, supporting the hypothesis that epizootics bypass regions of enzootic transmission due to natural immunization of equines by enzootic VEE viruses.

Animals↗
PubMed2001

Sources of variability: a College of American Pathologists Therapeutic Drug Monitoring study.

OBJECTIVE: To determine the magnitudes and sources of analytic variation in testing for therapeutic drugs. Specifically, among laboratories using the same analytic method, to compare the within-laboratory variation (including both short- and long-term variation) with the between-laboratory variation. DESIGN: Four identical challenges were prepared from a lyophilized pool of spiked sera and were sent in pairs 4 months apart to laboratories participating in a nationwide proficiency-testing program. For each of 25 drugs, the variability in reported results from laboratories using the same method was investigated using nested analysis of variance. SETTING: The first 2 mailings of the College of American Pathologists Therapeutic Drug Monitoring Survey, 1996, sets Z and ZM. MAIN OUTCOME MEASURES: For each drug, total variance was partitioned into within- and between-laboratory components for common methods. The within-laboratory component was further partitioned into short- and long-term components. PARTICIPANTS: The approximately 5000 laboratories enrolled in the survey. RESULTS: For the 25 drugs, the average percentages of the total variance due to short-term, within-laboratory variance; long-term, within-laboratory variance; between-laboratory variance; and total laboratory variance were 25.0% (range, 8.8--50.6%), 57.8% (35.3--73.7%), 17.3% (5.0--35.4%), and 82.7% (64.6--95.0%), respectively. CONCLUSION: For all drugs tested, the within-laboratory component of variance was greater than the between-laboratory component of variance. Within laboratories, the magnitude of the long-term component was generally greater than the magnitude of the short-term component. This information will be helpful in determining the clinical utility of various drug assays and in evaluating the appropriateness of regulations involving therapeutic drug testing.

Analysis of Variance↗
PubMed2001

An evaluation of analytic goals for assays of drugs: a College of American Pathologists Therapeutic Drug Monitoring Survey Study.

OBJECTIVE: To determine if the levels of imprecision of the commonly used analytic methods for drug measurements are suitable for long-term therapeutic drug monitoring. DESIGN: In 1996, 4 identical lyophilized samples (2 in the first mailing and 2 in the second mailing 4 months later) were sent to laboratories participating in a nationwide proficiency testing program. Similarly, in 1999, replicates from a liquid pool of spiked sera were mailed 3 times, 4 months apart, to participating laboratories. For each of 11 drugs regulated under the Clinical Laboratory Improvement Amendments of 1988 and 1 metabolite, the total variance for each method was partitioned into within- and between-laboratory components. The total within-laboratory and the total survey coefficients of variation (CVs) for each method were then compared with the "acceptable" precision criteria of Glick, Burnett, and Fraser for each drug. SETTING: The first 2 mailings of the College of American Pathologists Therapeutic Drug Monitoring surveys for 1996, sets Z and ZM, and the 3 mailings of 1999, sets ZM, Z, and Z2. MAIN OUTCOME MEASURES: For each drug studied, the CV of each method was compared with the various imprecision criteria, and if greater than any of the criteria, the method was then tabulated as not meeting that specific criterion.Participants.-The approximately 5000 participants of the survey. RESULTS: The number of methods deemed as not having acceptable total long-term within-laboratory precision by the various criteria ranged from 35% to 88% in 1996 and from 22% to 77% in 1999. CONCLUSION: The number of failures possibly indicates that many of the reagent assays being utilized are not precise enough for long-term therapeutic drug monitoring of chronically administered drugs or that the published criteria used to evaluate the data in this study are too stringent.

Data Collection↗
PubMed2001

Rosai-Dorfman disease presenting with isolated bilateral orbital masses: report of two cases.

Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy) is a rare benign idiopathic proliferative disease of phagocytic histiocytes. Approximately 80% of patients present with painless massive cervical lymphadenopathy. Isolated extranodal involvement is relatively uncommon. Two cases of Rosai-Dorfman disease are reported: one with isolated bilateral orbital involvement and one with marked cervical lymphadenopathy and multiple dural-based and intraventricular masses.

Adult↗
PubMed2001

[Comparison and analysis of clinicopathology of lung cancer between 1980s and 1990s in the Shenyang area (1,224 cases)].

OBJECTIVE: To compare the changes in pathogenetis and histopathology of lung cancer between 1980s and 1990s in the Shenyang area. METHODS: The HE stained sections of 572 cases of lung cancer from 1981-1990 and 652 cases from 1991-2000 were reviewed. Parts of these samples were also studied with immunohistochemistry and in situ hybridization. RESULTS AND CONCLUSIONS: By comparing the finding in the 1980s and those of the 1990s, it was found that (1) the incidence of lung cancer in women increased. (2) the highest incidence occurred in the 61 to 70 year of old group in 1990s, in 1980s it was 51-60 years. (3) there was an increased incidence of adenocarcinoma, especially papillary adenocarcinoma and acinar adenocarcinoma and bronchioloalveolar carcinoma in the 1990s.

Adult↗
PubMed2001

[A prospective study of histological changes after AraAMP treatment in patients with chronic hepatitis B infection].

OBJECTIVE: To investigate the histological changes in liver biopsy tissue induced by AraAMP therapy for 50 days in patients with chronic hepatitis B infection. METHODS: Eleven patients were enrolled into this prospective study. All the patients had liver biopsy performed within 1 week before starting AraAMP therapy. A second liver biopsy was taken for comparison six months after the end of therapy. Blinded biopsies were scored according to Knodell's histology activity index (HAI), and examined for HBeAg and alpha-smooth muscle actin with immunohistochemistry as well as HBV DNA by using in situ hybridization. RESULTS: Histological improvement of >or=2 points decrease in the necroinflammatory HAI scores was seen in 8 of the 11 (72.7%) of patients after treatment. In these patients histological assessment revealed a significant improvement in intralobular inflammation and fibrosis as compared with pretreatment values(P < 0.05). There was significant difference of HAI changes in 6 cases graded as G3 based on the degree of periportal interface hepatitis and spotty parenchymal injury, but not in 5 cases graded as G2. HBeAg disappeared from liver tissue in 4 of the 9 cases and a significant reduction of activated liver stellate cells was demonstrated in the second biopsy(P = 0.018). Of the nine cases with HBV DNA positive at the first biopsy with in situ hybridization examination, 4 were negative at the second biopsy. CONCLUSION: Significant improvement in intralobular inflammation and fibrosis can be observed in liver tissue from patients with chronic hepatitis B infection treated with AraAMP.

Adolescent↗