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排序方式: 共有103条查询结果,搜索用时 546 毫秒
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Spatial Assessment of Heavy Metals in Surface Soil from Klang District (Malaysia): An Example from a Tropical Environment 总被引:1,自引:0,他引:1
Sarva Mangala Praveena Biswajeet Pradhan Sharifah Norkhadijah Syed Ismail 《人类与生态风险评估》2015,21(7):1980-2003
Heavy metals (Al, Cd, Co, Cr, Cu, Fe, Pb, Zn) in surface soil of Klang district were determined and multivariate analysis was used to understand their potential sources. The total and bioavailability of concentrations were used in identifying the potential risks to the ecology and human health. The means for the total heavy metal concentrations were found to be in the order of Fe > Al > Zn > Pb > Cu > Cr > Co > Cd, while the means for the bioavailability concentrations were found to be in the order of Al > Fe > Zn > Cu > Co > Cd > Pb > Cr. Principal Component Analysis showed Principal Component 1 as being of natural origin whereas Principal Components 2, 3, and 4 were associated with mixed anthropogenic sources, such as traffic and industrial emissions, organic matter, and granulometric fractions. Potential ecological risk assessment indicated an overall low ecological risk. Spatial assessment of non-carcinogenic risks showed that the Hazard Index values were more than one in Johan Setia, due to biomass burning of peat swamps exploited for agricultural development. While for spatial assessment of carcinogenic risks, the Lifetime Cancer Risk values were in the limit (1 × 10?5), indicating low cancer inducing risks. Nevertheless, with intense development pressure in the Klang district could overlap pollution inputs in the future. 相似文献
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Zoltan Beck Bruce K. Brown Lindsay Wieczorek Kristina K. Peachman Gary R. Matyas Victoria R. Polonis Mangala Rao Carl R. Alving 《PloS one》2009,4(12)
Although CD4(+) cells represent the major target for HIV infection in blood, claims of complement-independent binding of HIV-1 to erythrocytes and the possible role of Duffy blood group antigen, have generated controversy. To examine the question of binding to erythrocytes, HIV-1 was incubated in vitro with erythrocytes from 30 healthy leukapheresis donors, and binding was determined by p24 analysis and adsorption of HIV-1 with reduction of infectivity for CD4(+) target cells. All of the cells, regardless of blood group type, bound HIV-1 p24. A typical preparation of erythrocytes bound <2.4% of the added p24, but erythrocytes selectively removed essentially all of the viral infectivity as determined by decreased infection of CD4(+) target cells; however, cell-associated HIV-1 was approximately 100-fold more efficient, via trans infection, than unadsorbed virus for infection of CD4(+) cells. All of the bound HIV-1 p24 was released by treatment of the cells with EDTA, and binding was optimized by adding Ca2+ and Mg2+ during the washing of erythrocytes containing bound HIV-1. Although the small number of contaminating leukocytes in the erythrocyte preparation also bound HIV-1 p24, there was no significant binding to CD4, and it thus appears that the binding occurred on leukocytes at non-CD4 sites. Furthermore, binding occurred to erythrocyte ghosts from which contaminating leukocytes had been previously removed. The results demonstrate that erythrocytes incubated in vitro with HIV-1 differentially adsorb all of the infectious HIV-1 virions (as opposed to non-infectious or degraded virions) in the absence of complement and independent of blood group, and binding is dependent on divalent cations. By analogy with HIV-1 bound to DC-SIGN on dendritic cells, erythrocyte-bound HIV-1 might comprise an important surface reservoir for trans infection of permissive cells. 相似文献
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Sonali Vora Asad Abbas Chong J Kim Taryn LS Summerfield Juan P Kusanovic Jay D Iams Roberto Romero Douglas A Kniss William E AckermanIV 《Reproductive biology and endocrinology : RB&E》2010,8(1):8
Background
The objective of this study was to quantify the nuclear localization and DNA binding activity of p65, the major transactivating nuclear factor-kappa B (NF-kappaB) subunit, in full-thickness fetal membranes (FM) and myometrium in the absence or presence of term or preterm labor. 相似文献27.
Mucins comprise an important class of tumor-associated antigens. The objectives of the present study were (a) to establish an in vitro model system using human non-small cell lung adenocarcinoma cell lines NCIH650 and NCIH2077 (b) provide evidence that these cell lines secrete mucin in culture conditions and (c) investigate the effects of select secretagogues on mucin secretion. The cell lines were established in ACL-4 medium containing several growth factors and retinoic acid and 5% fetal calf serum. The high molecular weight glycoconjugates secreted in the culture medium were purified by ammonium sulfate precipitation and Superose 6 and Superose 12 FPLC chromatography. The purified high molecular weight glycoconjugate fraction and the carcinoma cells were shown to have mucin by dot blot, Western blot and immunohistochemical analysis, respectively, using specific antibodies to purified major mucin, HTM-1. Also, incorporation experiments with mucin precursor 3H-glucosamine demonstrated that the cells indeed synthesize high molecular weight mucins. The effects of secretagogues such as, 8-bromocyclic AMP, ionomycin, phorbol-12-myristate-13-acetate and neutrophil elastase on mucin secretion were also investigated. Only 8-bromocyclic AMP and neutrophil elastase influenced mucin secretion. These studies provided strong evidence that the lung adenocarcinoma cell lines secrete high molecular weight mucins in culture conditions and only two of the four tested secretagogues significantly increased mucin secretion. Thus, this in vitro model system may be useful in determining alterations in mucin structure, if any, in lung adenocarcinomas as well as in studying the regulation of mucin gene expression. 相似文献
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Induction of immune responses in mice and monkeys to Ebola virus after immunization with liposome-encapsulated irradiated Ebola virus: protection in mice requires CD4(+) T cells
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Ebola Zaire virus (EBO-Z) causes severe hemorrhagic fever in humans, with a high mortality rate. It is thought that a vaccine against EBO-Z may have to induce both humoral and cell-mediated immune responses to successfully confer protection. Because it is known that liposome-encapsulated antigens induce both antibody and cellular responses, we evaluated the protective efficacy of liposome-encapsulated irradiated EBO-Z [L(EV)], which contains all of the native EBO-Z proteins. In a series of experiments, mice immunized intravenously with L(EV) were completely protected (94/94 mice) against illness and death when they were challenged with a uniformly lethal mouse-adapted variant of EBO-Z. In contrast, only 55% of mice immunized intravenously with nonencapsulated irradiated virus (EV) survived challenge, and all became ill. Treatment with anti-CD4 antibodies before or during immunization with L(EV) eliminated protection, while treatment with anti-CD8 antibodies had no effect, thus indicating a requirement for CD4(+) T lymphocytes for successful immunization. On the other hand, treatment with either anti-CD4 or anti-CD8 antibodies after immunization did not abolish the protection. After immunization with L(EV), antigen-specific gamma interferon (IFN gamma)-secreting CD4(+) T lymphocytes were induced as analyzed by enzyme-linked immunospot assay. Anti-CD4 monoclonal antibody treatment abolished IFN gamma production (80 to 90% inhibition compared to that for untreated mice). Mice immunized with L(EV), but not EV, developed cytotoxic T lymphocytes specific to two peptides (amino acids [aa] 161 to 169 and aa 231 to 239) present in the amino-terminal end of the EBO-Z surface glycoprotein. Because of the highly successful results in the mouse model, L(EV) was also tested in three cynomolgus monkeys. Although immunization of the monkeys with L(EV)-induced virus-neutralizing antibodies against EBO-Z caused a slight delay in the onset of illness, it did not prevent death. 相似文献
29.
Safia S. Aljedani Tyler J. Liban Karen Tran Ganesh Phad Suruchi Singh Viktoriya Dubrovskaya Pradeepa Pushparaj Paola Martinez-Murillo Justas Rodarte Alex Mileant Vidya Mangala Prasad Rachel Kinzelman Sijy ODell John R. Mascola Kelly K. Lee Gunilla B. Karlsson Hedestam Richard T. Wyatt Marie Pancera 《PLoS pathogens》2021,17(9)
Understanding the molecular mechanisms by which antibodies target and neutralize the HIV-1 envelope glycoprotein (Env) is critical in guiding immunogen design and vaccine development aimed at eliciting cross-reactive neutralizing antibodies (NAbs). Here, we analyzed monoclonal antibodies (mAbs) isolated from non-human primates (NHPs) immunized with variants of a native flexibly linked (NFL) HIV-1 Env stabilized trimer derived from the tier 2 clade C 16055 strain. The antibodies displayed neutralizing activity against the autologous virus with potencies ranging from 0.005 to 3.68 μg/ml (IC50). Structural characterization using negative-stain EM and X-ray crystallography identified the variable region 2 (V2) of the 16055 NFL trimer to be the common epitope for these antibodies. The crystal structures revealed that the V2 segment adopts a β-hairpin motif identical to that observed in the 16055 NFL crystal structure. These results depict how vaccine-induced antibodies derived from different clonal lineages penetrate through the glycan shield to recognize a hypervariable region within V2 (residues 184–186) that is unique to the 16055 strain. They also provide potential explanations for the potent autologous neutralization of these antibodies, confirming the immunodominance of this site and revealing that multiple angles of approach are permissible for affinity/avidity that results in potent neutralizing capacity. The structural analysis reveals that the most negatively charged paratope correlated with the potency of the mAbs. The atomic level information is of interest to both define the means of autologous neutralization elicited by different tier 2-based immunogens and facilitate trimer redesign to better target more conserved regions of V2 to potentially elicit cross-neutralizing HIV-1 antibodies. 相似文献
30.
Kristina K. Peachman Nicos Karasavvas Agnes-Laurence Chenine Robert McLinden Supachai Rerks-Ngarm Kaewkungwal Jaranit Sorachai Nitayaphan Punnee Pitisuttithum Sodsai Tovanabutra Susan Zolla-Pazner Nelson L. Michael Jerome H. Kim Carl R. Alving Mangala Rao 《PloS one》2015,10(12)