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1

Procaspase 8 and Bax Are Up-regulated by Distinct Pathways in Streptococcal Pyrogenic Exotoxin B-induced Apoptosis*  

PubMed Central

We have previously identified integrin ?v?3 and Fas as receptors for the streptococcal pyrogenic exotoxin B (SPE B), and G308S, a mutant of SPE B that binds to Fas only. In the current study we found that after binding to ?v?3, SPE B stimulated the tyrosine phosphorylation of JAK2 and STAT1. STAT1 tyrosine phosphorylation was inhibited by a JAK2 inhibitor, AG490, short interfering RNA (siRNA) silencing of JAK2, and anti-?V?3 antibody. AG490 also decreased the binding of tyrosine-phosphorylated STAT1 to the procaspase 8 promoter, decreasing procaspase 8 expression, suggesting that SPE B up-regulates procaspase 8 expression via the JAK2/STAT1 pathway. Alternatively, both SPE B and G308S increased STAT1 phosphorylation at serine 727, which was inhibited by anti-Fas antibody, a p38 inhibitor, SB203580, and siRNA silencing of p38. In addition, SPE B and G308S increased binding of serine-phosphorylated STAT1 to the Bax promoter and Bax expression, which was decreased by SB203580. SPE B and G308S-stimulated Bax expression was also inhibited by anti-Fas antibody. These findings suggest that Fas mediate SPE B-induced Bax expression through p38. Silencing of JAK2 or p38 by siRNA blocked procaspase 8 expression, whereas only p38 siRNA decreased Bax expression. Furthermore, JAK2 inhibition and p38 inhibition reduced SPE B-induced apoptosis, but only p38 inhibition blocked G308S-induced apoptosis.

Chang, Chia-Wen; Tsai, Wan-Hua; Chuang, Woei-Jer; Lin, Yee-Shin; Wu, Jiunn-Jong; Liu, Ching-Chuan; Tsai, Pei-Jane; Lin, Ming T.

2009-01-01

2

The hepatitis C virus NS2 protein is an inhibitor of CIDE-B-induced apoptosis.  

PubMed

Chronic hepatitis C virus (HCV) infection frequently leads to liver cancer. To determine the viral factor(s) potentially involved in viral persistence, we focused our work on NS2, a viral protein of unknown function. To assign a role for NS2, we searched for cellular proteins that interact with NS2. Performing a two-hybrid screen on a human liver cDNA library, we found that NS2 interacted with the liver-specific pro-apoptotic CIDE-B protein. Binding specificity of NS2 for CIDE-B was confirmed by cell-free assays associated with colocalization studies and coprecipitation experiments on human endogenous CIDE-B. CIDE-B, a member of the novel CIDE family of apoptosis-inducing factors, has been reported to show strong cell death-inducing activity in its C-terminal domain. We show that this CIDE-B killing domain is involved in the NS2 interaction. NS2 binding was sufficient to inhibit CIDE-B-induced apoptosis because an NS2 deletion mutant unable to interact with CIDE-B in vitro lost its capacity to interfere with CIDE-B cell death activity. Although it has been reported that CIDE-B-induced apoptosis is characterized by mitochondrial localization, the precise apoptotic mechanism remained unknown. Here, we show that CIDE-B induced cell death in a caspase-dependent manner through cytochrome c release from mitochondria. Furthermore, we found that NS2 counteracted the cytochrome c release induced by CIDE-B. In vivo, the CIDE-B protein level was extremely low in adenovirus-infected transgenic mice expressing the HCV polyprotein compared with that in wild-type mice. We suggest that NS2 interferes with the CIDE-B-induced death pathway and participates in HCV strategies to subvert host cell defense. PMID:12595532

Erdtmann, Lars; Franck, Nathalie; Lerat, Hervé; Le Seyec, Jacques; Gilot, David; Cannie, Isabelle; Gripon, Philippe; Hibner, Urszula; Guguen-Guillouzo, Christiane

2003-02-20

3

The Salmonella Invasin SipB Induces Macrophage Apoptosis by Binding to Caspase1  

Microsoft Academic Search

Recently, Salmonella spp. were shown to induce apoptosis in infected macrophages. The mechanism responsible for this process is unknown. In this report, we establish that the Inv-Spa type III secretion apparatus target invasin SipB is necessary and sufficient for the induction of apoptosis. Purified SipB microinjected into macrophages led to cell death. Binding studies show that SipB associates with the

David Hersh; Denise M. Monack; Mark R. Smith; Nafisa Ghori; Stanley Falkow; Arturo Zychlinsky

1999-01-01

4

NF-?B, inducible nitric oxide synthase and apoptosis by Helicobacter pylori infection  

Microsoft Academic Search

Oxygen radicals are considered as an important regulator in the pathogenesis of Helicobacter pylori (H. pylori)-induced gastric ulceration and carcinogenesis. Inflammatory genes including inducible nitric oxide synthase (iNOS) may be regulated by oxidant-sensitive transcription factor, nuclear factor-?B (NF-?B). iNOS induction has been related to gastric apoptosis. We studied the role of NF-?B on iNOS expression and apoptosis in H. pylori-stimulated

Joo Weon Lim; Hyeyoung Kim; Kyung Hwan Kim

2001-01-01

5

UV-B induced thymocytes apoptosis blocked by dicyclodextrinyl ditelluride-A GPX mimic.  

PubMed

Apoptosis is known to occur after ultraviolet-B (UV-B) radiation. It was found that UV-B could induce cell apoptosis and change cell cycle progression. After exposure to 100J/m(2) of UV-B, pre-G1 phase thymocytes were increased significantly and S phase thymocytes were decreased significantly. UV-B could also induce lipid peroxidation of thymocytes to have their MDA amount increased. These phenomena could be explained by production of reactive oxygen species (ROS), which were induced by UV-B radiation. In this study, we examined the protective effect of dicyclodextrinyl ditelluride (2-TeCD), the glutathione peroxidase (GPX, EC 1.11.1.9) mimics, on thymocytes apoptosis induced by UV-B radiation. The experimental results showed that 2-TeCD protects thymocytes from apoptosis. Moreover, 2-TeCD inhibits lipid peroxidation of thymocytes and displayed great antioxidant ability. Furthermore, 2-TeCD blocks the accumulation of wild-type-p53 (wt-p53) tumor-suppressor gene product caused by UV-B radiation. PMID:21787621

Wang, Linlin; Lv, Shaowu; Yan, Ganglin; Luo, Guimin; Mu, Ying

2010-03-19

6

The Role of Cholesterol In Ultraviolet Light B-Induced Apoptosis  

PubMed Central

Modification of major lipid raft components, such as cholesterol and ceramide, plays a role in regulation of programmed cell death under various stimuli. However, the relationship between cholesterol level modification and the activation of apoptotic signaling cascades upon ultraviolet B light has not been established. In this report, we demonstrate that upon UVB irradiation cholesterol levels in membrane rafts of skin cells increase, which leads to Fas aggregation in the rafts. Utilizing a continuous velocity floatation technique, we show that Fas accumulated in the lipid rafts of human melanoma M624 cells after UVB-irradiation. The subsequent events of DISC formation were also detected in the lipid raft fractions. Depletion of cholesterol by methyl-?-cyclodextrin reduces Fas aggregation, while overloading increases. Disruption of lipid rafts also prevents Daxx from dissociating from Fas in the lipid rafts, which is accompanied with a reduced apoptotic, but increased non-apoptotic death of UVB-irradiated human keratinocytes, HaCaT cells. Results indicate that cholesterol located in the plasma membrane of skin cells is required for lipid raft domain formation and activation of UVB-induced apoptosis.

George, Kimberly S.; Elyassaki, Walid; Wu, Qiong; Wu, Shiyong

2011-01-01

7

The role of cholesterol in UV light B-induced apoptosis.  

PubMed

Modification of major lipid raft components, such as cholesterol and ceramide, plays a role in regulation of programmed cell death under various stimuli. However, the relationship between cholesterol level modification and the activation of apoptotic signaling cascades upon UVB light has not been established. In this report, we demonstrate that upon UVB irradiation cholesterol levels in membrane rafts of skin cells increase, which leads to Fas-receptor (Fas) aggregation in the rafts. Utilizing a continuous velocity floatation technique, we show that Fas accumulated in the lipid rafts of human melanoma M624 cells after UVB irradiation. The subsequent events of death-inducing signaling complex formation were also detected in the lipid raft fractions. Depletion of cholesterol by methyl-?-cyclodextrin reduces Fas aggregation, while overloading increases. Disruption of lipid rafts also prevents Fas death domain-associated protein (Daxx) from dissociating from Fas in the lipid rafts, which is accompanied with a reduced apoptotic, but increased nonapoptotic death of UVB-irradiated human keratinocytes, HaCaT cells. Results indicate that cholesterol located in the plasma membrane of skin cells is required for lipid raft domain formation and activation of UVB-induced apoptosis. PMID:22077874

George, Kimberly S; Elyassaki, Walid; Wu, Qiong; Wu, Shiyong

2011-12-16

8

Indole-3-carbinol and ultraviolet B induce apoptosis of human melanoma cells via down-regulation of MITF.  

PubMed

We investigated the mechanism of indole-3-carbinol (13C)/ultraviolet B (UVB)-induced apoptosis using SK-MEL-2 and SK-MEL-5 human melanoma cells. 13C/UVB significantly reduced the viability of SK-MEL-2 cells, whereas it had little influence on SK-MEL-5 cells. Correspondingly, cell cycle analysis showed that 13C/UVB induced a clear increase in the sub-G0/G1 phase in SK-MEL-2 cells. Furthermore, 13C/UVB activated caspase-9, caspase-8, caspase-3, and Bid and caused the cleavage of poly(ADP-ribose) polymerase (PARP) in SK-MEL-2 cells. In contrast, 13C/UVB showed no effects on the apoptotic signaling pathways in SK-MEL-5 cells. Moreover, we found that 13C down-regulated the microphthalmia-associated transcription factor (MITF) in SK-MEL-2 cells, but not in SK-MEL-5 cells. Next, to investigate the involvement of MITF in 13C/UVB-induced apoptosis, MITF silencing was conducted using small interfering RNA (siRNA) for MITF in SK-MEL-5 cells. Interestingly, 13C/UVB dramatically decreased the viability of MITF-down-regulated SK-MEL-5 cells. These results indicate that MITF plays a critical role in melanoma cell survival. PMID:22312706

Kim, So-Young; Kima, Dong-Seok; Jeong, Yun-Mi; Moon, Sang-Ik; Kwon, Sun-Bang; Park, Kyoung-Chan

2011-12-01

9

Cytochalasin B induces apoptosis through the mitochondrial apoptotic pathway in HeLa human cervical carcinoma cells.  

PubMed

Cytochalasin B (CB) is a cell-permeable mycotoxin. It inhibits cytoplasmic division by blocking the formation of contractile microfilaments, it inhibits cell movement and induces nuclear extrusion. In the present study, we investigated the anticancer activity of CB in HeLa human cervical carcinoma cells. CB showed significant cytotoxicity, with an IC50 of 7.9 µM, in a WST-8 assay and significantly inhibited cell proliferation. Furthermore, results from Annexin V-FITC/propidium iodide double-staining indicated that CB induced early apoptosis of HeLa cells in a time-dependent manner. The cells exhibited apoptotic morphology, including cell shrinkage and nuclear condensation. CB induced cell cycle arrest at the S phase. We also observed inhibition of DNA replication in a [3H]-thymidine incorporation assay. Furthermore, CB induced a time-dependent increase in reactive oxygen species and a decrease in mitochondrial membrane potential. Western blot analysis showed an increase in levels of mitochondrial factors Bax and Bcl-2, which was followed by activation of caspase-9 and -3. These results suggested that CB induced apoptosis via a mitochondrial-dependent pathway in HeLa cells. PMID:23863920

Hwang, Jiyoung; Yi, Myeongjin; Zhang, Xin; Xu, Yi; Jung, Jee H; Kim, Dong-Kyoo

2013-07-17

10

SPE (TM) Electrolyzers for Space Propulsion.  

National Technical Information Service (NTIS)

Viewgraphs on SPE electrolyzers for space propulsion are presented. Topics covered include: SPE electrochemical cell reactions; SPE fuel cell/electrolyzer features; SPE cell life capability; SPE cell voltage stability; state-of-the-art SPE cell structure;...

E. M. Shane

1990-01-01

11

Jolkinolide B induces apoptosis in MCF-7 cells through inhibition of the PI3K/Akt/mTOR signaling pathway.  

PubMed

The aim of this study was to explore the molecular mechanisms of jolkinolide B (JB), which is extracted from the root of Euphorbia fischeriana Steud. In this study, we found that JB, a diterpenoid from the traditional Chinese medicinal herb, strongly inhibited the PI3K/Akt/mTOR signaling pathway. Furthermore, we evaluated the effects of JB on the proliferation and apoptosis of MCF-7 human breast cancer cells. Our results showed significant induction of apoptosis in MCF-7 cells incubated with JB. The viability of the MCF-7 cells was assessed by MTT assay. Flow cytometry was used to detect apoptosis and cell cycle analysis. Transmission electron microscopy (TEM) analysis was used to observe cell morphology. MCF-7 cells were subcutaneously inoculated into nude mice to study the in vivo antitumor effects of JB. The growth of MCF-7 cells was inhibited and arrested in the S phase by JB. The data showed significantly decreased tumor volume and weight in nude mice inoculated with MCF-7 cells. In addition, treatment with JB was able to induce downregulation of cyclinD1, cyclinE, mTOR, p-PI3K and p-Akt, and upregulation of PTEN and p-eIF4E. Collectively, JB-induced apoptosis of MCF-7 cells occurs through the PI3K/Akt/mTOR signaling pathway. Furthermore, the PI3K/Akt signaling cascade plays a role in the induction of apoptosis in JB-treated cells. These observations suggest that JB may have therapeutic applications in the treatment of cancer. PMID:23129237

Xu, Hui-Yu; Chen, Zhi-Wei; Hou, Jin-Cai; Du, Feng-Xia; Liu, Ji-Cheng

2012-10-31

12

ARID3B Induces Tumor Necrosis Factor Alpha Mediated Apoptosis While a Novel ARID3B Splice Form Does Not Induce Cell Death  

PubMed Central

Alternative splicing is a common occurrence in many cancers. Alternative splicing is linked with decreased apoptosis and chemoresistance in cancer cells. We previously demonstrated that ARID3B, a member of the AT-rich interactive domain (ARID) family of DNA binding proteins, is overexpressed in ovarian cancer. Therefore we wanted to assess the effect of ARID3B splice forms on cell viability. We identified a novel splice form of the ARID3B gene (designated as ARID3B Sh), which lacks the C-terminal exons 5–9 present in the full-length isoform (ARID3B Fl). ARID3B Fl is expressed in a variety of cancer cell lines. Expression of ARID3B Sh varied by cell type, but was highly expressed in most ovarian cancer lines. ARID3B is modestly transcriptionally activated by epidermal growth factor receptor (EGFR) signaling through the PEA3 transcription factor. We further found that ARID3B Fl is predominantly nuclear but is also present at the plasma membrane and in the cytosol. Endogenous ARID3B Sh is present in nuclear fractions, yet, when overexpressed ARID3B Sh accumulates in the cytosol and membrane fractions. The differential localization of these isoforms suggests they have different functions. Importantly, ARID3B Fl overexpression results in upregulation of pro-apoptotic BIM and induces Tumor Necrosis Factor alpha (TNF?) and TNF-related apoptosis inducing ligand (TRAIL) induced cell death. The ARID3B Fl-induced genes include TNF?, TRAIL, TRADD, TNF-R2, Caspase 10 and Caspase 7. Interestingly, ARID3B Sh does not induce apoptosis or expression of these genes. ARID3B Fl induces death receptor mediated apoptosis while the novel splice form ARID3B Sh does not induce cell death. Therefore alternative splice forms of ARID3B may play different roles in ovarian cancer progression.

Joseph, Stancy; Deneke, Victoria E.; Cowden Dahl, Karen D.

2012-01-01

13

Flavokawain B induces apoptosis of human oral adenoid cystic cancer ACC-2 cells via up-regulation of Bim and down-regulation of Bcl-2 expression.  

PubMed

Novel effective drugs are still urgently needed in the prevention and treatment of oral adenoid cystic carcinoma (ACC). In this study, we have assessed the antitumor potential and molecular mechanisms of flavokawain B (FKB) as a kava chalcone on the ACC-2 cell line in vitro. The results demonstrated that FKB could significantly inhibit the cell proliferation of ACC-2 in a dose-dependent manner that was associated with induced apoptosis and cell cycle G2-M arrest, and the half maximal inhibitory concentration (IC(50)) of flavokawain-B treatment for 48 h was estimated to be 4.69 ± 0.43 µmol/L. Mechanistically, FKB could induce the release of cytochrome c from mitochondria into the cytosol, and activate the cleavage of caspase-3 and, eventually, the poly(ADP-ribose) polymerase (PARP), in a dose-dependent manner, leading to marked apoptotic effect of ACC-2 cells. The apoptotic action of FKB was associated with the increased expression of proapoptotic proteins: Bim, Bax, Bak and a decreased expression of antiapoptotic Bcl-2. Among them, Bim expression was significantly induced by FKB, and knockdown of Bim expression by short-hairpin RNAs attenuated the inhibitory effect induced by FKB on ACC-2 cells. These results suggest Bim may be one of the potential transcriptional targets, and suggests the potential usefulness of FKB for the prevention and treatment of ACC. PMID:22115332

Zhao, Xi; Chao, Yong-Lie; Wan, Qian-Bing; Chen, Xin-Min; Su, Peng; Sun, Jian; Tang, Yaxiong

2011-11-24

14

PEM/SPE fuel cell  

DOEpatents

A PEM/SPE fuel cell is described including a membrane-electrode assembly (MEA) having a plurality of oriented filament embedded the face thereof for supporting the MEA and conducting current therefrom to contiguous electrode plates. 4 figs.

Grot, S.A.

1998-01-13

15

Apoptosis  

NSDL National Science Digital Library

Apoptosis is a highly orchestrated form of cell death in which cells neatly commit suicide by chopping themselves into membrane-packaged bits. Apoptosis, also known as programmed cell death, has caught the imagination of researchers worldwide. This article introduces a special issue on apoptosis.

Linda J. Miller (AAAS;); Jean Marx (AAAS;)

1998-08-28

16

Apoptosis  

NSDL National Science Digital Library

This Teaching Resource provides lecture notes and slides for a class covering apoptosis and is part of the course "Cell Signaling Systems: A Course for Graduate Students." The lecture contains a discussion of the apoptosis genes in Caenorhabditis elegans, the properties of the caspases, the major components of the extrinsic apoptotic signal transduction pathway, and the major components of the intrinsic (mitochondrial) apoptotic pathway.

Sherwin Wilk (Mount Sinai School of Medicine;Department of Pharmacology and Biological Chemistry REV)

2005-05-24

17

Leptomycin B-induced apoptosis is mediated through caspase activation and down-regulation of Mcl-1 and XIAP expression, but not through the generation of ROS in U937 leukemia cells  

Microsoft Academic Search

Leptomycin B (LMB), which is originally isolated from Streptomyces, possesses anti-tumor properties in vivo and in vitro. Though it was previously reported that LMB induces cell cycle arrest and p53-mediated apoptosis in certain cancer cells, however, the mechanism by which LMB induces apoptosis remains poorly understood. Here, we investigated the mechanisms of apoptosis induced by LMB in U937 cells. Treatment

Byeong-Churl Jang; Ji-Hye Paik; Hye-Yun Jeong; Hyun-Ji Oh; Jong-Wook Park; Taeg Kyu Kwon; Dae-Kyu Song; Jong-Gu Park; Sang-Pyo Kim; Jae-Hoon Bae; Kyo-Chul Mun; Min-Ho Suh; Minoru Yoshida; Seong-II Suh

2004-01-01

18

Photoelectrochemical characteristics of semiconductor-metal/SPE/metal cells  

SciTech Connect

A solid polymer electrolyte (SPE) photoelectrochemical cell, semiconductor-metal/SPE/Pt, is proposed as a new device to convert solar energy to electrical and/or chemical energy. The photoelectrochemical characteristics of TiO2-Pt/SPE and TiO2-Au/SPE were studied as well as those of the whole cell systems TiO2-Pt/SPE/Pt and TiO2-Au/SPE/Pt. By above-band gap energy illumination of the TiO2-metal side, negative photovoltage and anodic photocurrent were observed, as reported at TiO2 electrodes. In whole cell systems, i.e., TiO2-Pt/SPE/Pt and TiO2-Au/SPE/Pt, the conversion of light to electricity was achieved without using electrolyte solution.

Uosaki, K.; Kita, H.

1983-11-01

19

SPE Water Electrolyzers in Support of the Lunar Outpost.  

National Technical Information Service (NTIS)

During the 1970s, the SPE water electrolyzer, which uses ion exchange membranes as its sole electrolyte, was developed for nuclear submarine metabolic oxygen production. These developments included SPE water electrolyzer operation at up to 3,000 psia and ...

J. F. Mcelroy

1992-01-01

20

SPE44 Implements Sperm Cell Fate  

Microsoft Academic Search

The sperm\\/oocyte decision in the hermaphrodite germline of Caenorhabditis elegans provides a powerful model for the characterization of stem cell fate specification and differentiation. The germline sex determination program that governs gamete fate has been well studied, but direct mediators of cell-type-specific transcription are largely unknown. We report the identification of spe-44 as a critical regulator of sperm gene expression.

Madhura Kulkarni; Diane C. Shakes; Katie Guevel; Harold E. Smith

2012-01-01

21

Nuclear factor-? B inducing kinase is required for graft-versus-host disease  

PubMed Central

Background Donor T lymphocytes are directly responsible for graft-versus-host disease. Molecules important in T-cell function may, therefore, be appropriate targets for graft-versus-host disease therapy and/or prophylaxis. Here we analyzed whether nuclear factor-? B inducing kinase might have a role in graft-versus-host disease. Design and Methods We studied the expression of nuclear factor-? B inducing kinase in human samples from patients with graft-versus-host disease. We also explored the effect of nuclear factor-? B inducing kinase in a murine model of graft-versus-host disease using donor cells from aly/aly mice (deficient in nuclear factor-? B inducing kinase) and C57BL/6 mice (control). Results We detected expression of nuclear factor-? B inducing kinase in T-lymphocytes in the pathological lesions of patients with acute graft-versus-host disease. Mice transplanted with aly/aly T lymphocytes did not develop graft-versus-host disease at all, while mice receiving C57BL/6 cells died of a lethal form of the disease. Deficiency of nuclear factor-? B inducing kinase did not affect the engrafting ability of donor T cells, but severely impaired their expansion capacity early after transplantation, and aly/aly T cells showed a higher proportion of apoptosis than did C57BL/6 T cells. Effector T lymphocytes were the T-cell subset most affected by nuclear factor-? B inducing kinase deficiency. We also detected lower amounts of inflammatory cytokines in the serum of mice receiving aly/aly T cells than in the serum of mice receiving C57BL/6 T cells. Conclusions Our results show that nuclear factor-? B inducing kinase has a role in graft-versus-host disease by maintaining the viability of activated alloreactive T lymphocytes.

Sanchez-Valdepenas, Carmen; Casanova, Lucia; Colmenero, Isabel; Arriero, Mar; Gonzalez, Africa; Lozano, Nieves; Gonzalez-Vicent, Marta; Diaz, Miguel A.; Madero, Luis; Fresno, Manuel; Ramirez, Manuel

2010-01-01

22

The sperm surface localization of the TRP-3/SPE-41 Ca2+ -permeable channel depends on SPE-38 function in Caenorhabditis elegans.  

PubMed

Despite undergoing normal development and acquiring normal morphology and motility, mutations in spe-38 or trp-3/spe-41 cause identical phenotypes in Caenorhabditis elegans-mutant sperm fail to fertilize oocytes despite direct contact. SPE-38 is a novel, four-pass transmembrane protein and TRP-3/SPE-41 is a Ca(2+)-permeable channel. Localization of both of these proteins is confined to the membranous organelles (MOs) in undifferentiated spermatids. In mature spermatozoa, SPE-38 is localized to the pseudopod and TRP-3/SPE-41 is localized to the whole plasma membrane. Here we show that the dynamic redistribution of TRP-3/SPE-41 from MOs to the plasma membrane is dependent on SPE-38. In spe-38 mutant spermatozoa, TRP-3/SPE-41 is trapped within the MOs and fails to reach the cell surface despite MO fusion with the plasma membrane. Split-ubiquitin yeast-two-hybrid analyses revealed that the cell surface localization of TRP-3/SPE-41 is likely regulated by SPE-38 through a direct protein-protein interaction mechanism. We have identified sequences that influence the physical interaction between SPE-38 and TRP-3/SPE-41, and show that these sequences in SPE-38 are required for fertility in transgenic animals. Despite the mislocalization of TRP-3/SPE-41 in spe-38 mutant spermatozoa, ionomycin or thapsigargin induced influx of Ca(2+) remains unperturbed. This work reveals a new paradigm for the regulated surface localization of a Ca(2+)-permeable channel. PMID:22425620

Singaravelu, Gunasekaran; Chatterjee, Indrani; Rahimi, Sina; Druzhinina, Marina K; Kang, Lijun; Xu, X Z Shawn; Singson, Andrew

2012-03-09

23

Reciprocal, Temporal Expression of SpeA and SpeB by Invasive M1T1 Group A Streptococcal Isolates In Vivo  

Microsoft Academic Search

The streptococcal pyrogenic exotoxins (Spes) play a central role in the pathogenesis of invasive group A streptococcal (GAS) infections. The majority of recent invasive GAS infections have been caused by an M1T1 strain that harbors the genes for several streptococcal superantigens, including speA, speB, speF, speG, and smeZ. However, considerable variation in the expression of Spe proteins among clonal M1

SHAHANA U. KAZMI; RITA KANSAL; RAMY K. AZIZ; MASSOUMEH HOOSHDARAN; ANNA NORRBY-TEGLUND; D. E. Low; ABDEL-BASET HALIM; MALAK KOTB

2001-01-01

24

Soy protein extract (SPE) exhibits differential in vitro cell proliferation effects in oral cancer and normal cell lines.  

PubMed

Prior research has demonstrated that specific isoflavones derived from soy may exhibit antitumor effects against many cancers, including oral cancer. Most of this prior research involved isolation and testing of individual soy components, such as genistein, daidzein, and glycitein, which exhibit cytotoxicity against cancerous cells but may also have residual cytotoxic effects on normal cells. Few studies have evaluated whole soy extract, containing a combination of these isoflavones, and other bioreactive compounds, which may function synergistically and more effectively against oral cancers. This study compared the antiproliferative effects of whole soy protein extract (SPE) on CAL 27 and SCC25 oral cancer cell lines in vitro. Administration of SPE significantly inhibited oral cancer growth and exerted these effects at lower concentrations compared with another class of flavonoids (proanthocyanidins) that were previously tested on these cell lines. This SPE-induced growth inhibition correlated with down-regulated mRNA expression in the oral cancer cell-cycle promoter ornithine decarboxylase (ODC), as well as upregulation of caspase-2 and caspase-8, initiators and effectors of apoptosis. These results suggest that SPE may represent a potential chemopreventive or chemotherapeutic option for oral cancer. Moreover, SPE may be more effective than other flavonoids currently used and may be effective at lower concentrations that approximate physiologic serum levels (0-2 ?mol/l). This study may help to explain why diets rich in fruits, vegetables, and soy protein are associated with protection against development and progression of oral cancers, although further study is needed to develop specific public health recommendations for oral cancer treatment and prevention. PMID:22432688

Kingsley, Karl; Truong, Khanh; Low, Erik; Hill, Charles K; Chokshi, Shruti B; Phipps, Don; West, M Abigail; Keiserman, Mark A; Bergman, Christine J

2011-06-01

25

SPE (tm) regenerative hydrogen\\/oxygen fuel cells for extraterrestrial surface and microgravity applications  

Microsoft Academic Search

Viewgraphs on SPE regenerative hydrogen\\/oxygen fuel cells for extraterrestrial surface and microgravity applications are presented. Topics covered include: hydrogen-oxygen regenerative fuel cell energy storage system; electrochemical cell reactions; SPE cell voltage stability; passive water removal SPE fuel cell; fuel cell performance; SPE water electrolyzers; hydrophobic oxygen phase separator; hydrophilic\\/electrochemical hydrogen phase separator; and unitized regenerative fuel cell.

J. F. McElroy

1990-01-01

26

SPE (tm) regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications  

NASA Astrophysics Data System (ADS)

Viewgraphs on SPE regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications are presented. Topics covered include: hydrogen-oxygen regenerative fuel cell energy storage system; electrochemical cell reactions; SPE cell voltage stability; passive water removal SPE fuel cell; fuel cell performance; SPE water electrolyzers; hydrophobic oxygen phase separator; hydrophilic/electrochemical hydrogen phase separator; and unitized regenerative fuel cell.

McElroy, J. F.

27

Amphotericin B induced abnormalities in human platelets  

PubMed Central

Aims—To investigate in vitro the effect of amphotericin B on platelets in order to understand poor platelet recovery in patients receiving platelet transfusions and amphotericin B simultaneously. Methods—Washed platelets were isolated from platelet concentrates and exposed to amphotericin B (4 ?g/ml) for one hour. Platelet function was assessed by aggregation response to thrombin (0-0.6 U/ml), serotonin release, response to hypotonic stress, and mean platelet volume. The expression of surface membrane glycoprotein (GP) Ib-IX complex, GPIIb-IIIa complex and CD62P (P-selectin) was examined by flow cytometry using fluorescence labelled monoclonal antibodies. Heterotypic cell adhesion was measured in amphotericin B treated platelets coincubated with isolated, autologous polymorphonuclear leucocytes (PMN) by flow cytometric analysis. Results—Amphotericin B induced platelet dysfunction. The rate of aggregation by thrombin, serotonin uptake and thrombin induced release of serotonin, and the response of platelets to hypotonic stress were inhibited. There was up to a two-fold increase in the mean platelet volume. The expression of platelet surface GPIb-IX and GPIIb-IIIa was not affected. P-selectin, normally expressed only on the surface of activated platelets, was also expressed on unactivated platelets. Amphotericin B increased platelet adherence to PMN and the number of platelets bound per PMN. Conclusions—In vitro, amphotericin B induces P-selectin expression on the surface of unactivated platelets and increases platelet adhesion to PMN, which is exacerbated by storage. Platelet dysfunction resulting from exposure to amphotericin B may contribute to poor platelet recovery in vivo when amphotericin B is administered concomitantly with platelet transfusion.

Pastakia, K B; Brownson, N E; Terle, D A; Poindexter, B J

1996-01-01

28

Spermiogenesis initiation in Caenorhabditis elegans involves a casein kinase 1 encoded by the spe-6 gene.  

PubMed Central

Immature spermatids from Caenorhabditis elegans are stimulated by an external activation signal to reorganize their membranes and cytoskeleton to form crawling spermatozoa. This rapid maturation, termed spermiogenesis, occurs without any new gene expression. To better understand this signal transduction pathway, we isolated suppressors of a mutation in the spe-27 gene, which is part of the pathway. The suppressors bypass the requirement for spe-27, as well as three other genes that act in this pathway, spe-8, spe-12, and spe-29. Eighteen of the suppressor mutations are new alleles of spe-6, a previously identified gene required for an early stage of spermatogenesis. The original spe-6 mutations are loss-of-function alleles that prevent major sperm protein (MSP) assembly in the fibrous bodies of spermatocytes and arrest development in meiosis. We have isolated the spe-6 gene and find that it encodes a predicted protein-serine/threonine kinase in the casein kinase 1 family. The suppressor mutations appear to be reduction-of-function alleles. We propose a model whereby SPE-6, in addition to its early role in spermatocyte development, inhibits spermiogenesis until the activation signal is received. The activation signal is transduced through SPE-8, SPE-12, SPE-27, and SPE-29 to relieve SPE-6 repression, thus triggering the formation of crawling spermatozoa.

Muhlrad, Paul J; Ward, Samuel

2002-01-01

29

Proceedings of the ninth SPE symposium on formation damage control  

SciTech Connect

This book contains the proceedings of the ninth SPE symposium on formation damage control. Topics covered include: factors affecting gravel placement on long deviated intervals, use of CT scanning in the investigation of damage to unconsolidated cores, simulation of sandstone acidizing of a damaged perforation, completion fluids design criteria and current technology weaknesses.

Not Available

1990-01-01

30

A simple model for solid polymer electrolyte (SPE) water electrolysis  

Microsoft Academic Search

Solid polymer electrolyte (SPE) water electrolysis is analyzed by a simple model based on Butler–Volmer kinetics for electrodes and transport resistance in the polymer electrolyte. An equivalent electrical circuit analogy is provided for the sequential kinetic and transport resistances. The model provides a relation between applied terminal voltage of the electrolysis cell and current density in terms of Nernst potential,

Pyoungho Choi; Dmitri G. Bessarabov; Ravindra Datta

2004-01-01

31

SPE (TM) Water Electrolyzers in Support of Mission from Planet Earth.  

National Technical Information Service (NTIS)

During the 1970's, the Solid Polymer Electrolyte (SPE) water electrolyzer, which uses ion exchange membranes as its sole electrolyte, was developed for nuclear submarine metabolic oxygen production. SPE water electrolyzer developments included operation a...

J. F. Mcelroy

1991-01-01

32

SPE (TM) Regenerative Hydrogen/Oxygen Fuel Cells for Extraterrestrial Surface and Microgravity Applications.  

National Technical Information Service (NTIS)

Viewgraphs on SPE regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications are presented. Topics covered include: hydrogen-oxygen regenerative fuel cell energy storage system; electrochemical cell reactions; SPE c...

J. F. Mcelroy

1990-01-01

33

SPE (tm) water electrolyzers in support of mission from planet Earth  

NASA Astrophysics Data System (ADS)

During the 1970's, the Solid Polymer Electrolyte (SPE) water electrolyzer, which uses ion exchange membranes as its sole electrolyte, was developed for nuclear submarine metabolic oxygen production. SPE water electrolyzer developments included operation at up to 3,000 psia and at current densities in excess of 1,000 amps per square foot. The SPE water electrolyzer system has accumulated tens of thousands of system hours with the Navies of both the United States and the United Kingdom. During the 1980's, the basic SPE water electrolyzer cell structure developed for the Navies was incorporated into several demonstrators for NASA's Space Station Program. Among these were: (1) the SPE regenerative fuel cell for electrical energy storage; (2) the SPE water electrolyzer for metabolic oxygen production; and (3) the high pressure SPE water electrolyzer for reboost propellant production. In the 1990's, emphasis will be the development of SPE water electrolyzers for Mission from Planet Earth. Currently defined potential applications for the SPE water electrolyzer include: (1) SPE water electrolyzers operating at high pressure as part of a regenerative fuel cell extraterrestrial surface energy storage system; (2) SPE water electrolyzers for propellant production from extraterrestrial indigenous materials; and (3) SPE water electrolyzers for metabolic oxygen and potable water production from reclaimed water.

McElroy, J. F.

1991-09-01

34

Fiber-packed SPE tips based on electrospun fibers  

Microsoft Academic Search

A novel fiber-packed solid-phase extraction (SPE) tip was designed based on electrospun nanofibers. The tip was used to investigate\\u000a the extraction of hydrocortisone (HC), cortisone acetate (CA), ethinylestradiol (EE), and estradiol (E2). The effects of diameters,\\u000a porous figurations, and functional groups of the electrospun fibers on the selectivity and efficiency were studied. The experimental\\u000a results indicated that the detection limit

Yiyun Zhang; Xuejun Kang; Liqin Chen; Chao Pan; Yingfang Yao; Zhong-Ze Gu

2008-01-01

35

HPLC-SPE-NMR in pharmaceutical development: capabilities and applications.  

PubMed

High-performance liquid chromatography-solid phase extraction-NMR spectroscopy (HPLC-SPE-NMR) has recently become commercially available and has been evaluated with regard to its applicability in a pharmaceutical environment. The addition of an automated SPE unit to an HPLC-NMR system for peak trapping results in an improved NMR signal-to-noise ratio (S/N) and also has other practical advantages. The trapping efficiency is shown to depend on compound polarity and is highest for compounds eluting late on reversed-phase HPLC systems. Multiple peak trapping further increases the S/N, again with the best results for less polar compounds. For polar compounds, multiple peak trapping resulted in no S/N gain as the amount of material retained on the SPE cartridge was equivalent to that from a single injection. When compared with conventional HPLC-NMR, a S/N gain of up to five-fold could be achieved for some compounds in a single trapping step. A major advantage of the technique is the independence of the chromatographic step from the NMR step, resulting in greater versatility than conventional HPLC-NMR in the HPLC solvents and NMR solvents that can be used. Practical applications from both drug metabolite and drug impurity identification are presented. PMID:16049946

Sandvoss, Martin; Bardsley, Ben; Beck, Tony L; Lee-Smith, Emma; North, Stephanie E; Moore, Peter J; Edwards, Andrew J; Smith, Richard J

2005-09-01

36

Dynamics of speB mRNA Transcripts in Streptococcus pyogenes  

PubMed Central

Streptococcus pyogenes (group A streptococcus [GAS]) is a human-specific pathogen that causes a variety of diseases ranging from superficial infections to life-threatening diseases. SpeB, a potent extracellular cysteine proteinase, plays an important role in the pathogenesis of GAS infections. Previous studies show that SpeB expression and activity are controlled at the transcriptional and posttranslational levels, though it had been unclear whether speB was also regulated at the posttranscriptional level. In this study, we examined the growth phase-dependent speB mRNA level and decay using quantitative reverse transcription-PCR (qRT-PCR) and Northern blot analyses. We observed that speB mRNA accumulated rapidly during exponential growth, which occurred concomitantly with an increase in speB mRNA stability. A closer observation revealed that the increased speB mRNA stability was mainly due to progressive acidification. Inactivation of RNase Y, a recently identified endoribonuclease, revealed a role in processing and degradation of speB mRNA. We conclude that the increased speB mRNA stability contributes to the rapid accumulation of speB transcript during growth.

Itzek, Andreas; Malke, Horst; Ferretti, Joseph J.

2012-01-01

37

SPE-NMR metabolite sub-profiling of urine.  

PubMed

NMR-based metabolite profiling of urine is a fast and reproducible method for detection of numerous metabolites with diverse chemical properties. However, signal overlap in the (1)H NMR profiles of human urine may hamper quantification and identification of metabolites. Therefore, a new method has been developed using automated solid-phase extraction (SPE) combined with NMR metabolite profiling. SPE-NMR of urine resulted in three fractions with complementary and reproducible sub-profiles. The sub-profile from the wash fraction (100 % water) contained polar metabolites; that from the first eluted fraction (10 % methanol-90 % water) semi-polar metabolites; and that from the second eluted fraction (100 % methanol) aromatic metabolites. The method was validated by analysis of urine samples collected from a crossover human nutritional intervention trial in which healthy volunteers consumed capsules containing a polyphenol-rich mixture of red wine and grape juice extract (WGM), the same polyphenol mixture dissolved in a soy drink (WGM_Soy), or a placebo (PLA), over a period of five days. Consumption of WGM clearly increased urinary excretion of 4-hydroxyhippuric acid, hippuric acid, 3-hydroxyphenylacetic acid, homovanillic acid, and 3-(3-hydroxyphenyl)-3-hydroxypropionic acid. However, there was no difference between the excreted amounts of these metabolites after consumption of WGM or WGM_Soy, indicating that the soy drink is a suitable carrier for WGM polyphenols. Interestingly, WGM_Soy induced a significant increase in excretion of cis-aconitate compared with WGM and PLA, suggesting a higher demand on the tricarboxylic acid cycle. In conclusion, SPE-NMR metabolite sub-profiling is a reliable and improved method for quantification and identification of metabolites in urine to discover dietary effects and markers of phytochemical exposure. PMID:22932811

Jacobs, Doris M; Spiesser, Laura; Garnier, Maxime; de Roo, Niels; van Dorsten, Ferdi; Hollebrands, Boudewijn; van Velzen, Ewoud; Draijer, Richard; van Duynhoven, John

2012-08-31

38

Novel Chimeric Spermidine Synthase-Saccharopine Dehydrogenase Gene (SPE3LYS9) in the Human Pathogen Cryptococcus neoformans  

Microsoft Academic Search

The Cryptococcus neoformans LYS9 gene (encoding saccharopine dehydrogenase) was cloned and found to be part of an evolutionarily conserved chimera with SPE3 (encoding spermidine synthase). spe3-lys9, spe3-LYS9, and SPE3-lys9 mutants were constructed, and these were auxotrophic for lysine and spermidine, spermidine, and lysine, respectively. Thus, SPE3-LYS9 encodes functional spermidine synthase and saccharopine dehydro- genase gene products. In contrast to Saccharomyces

Joanne M. Kingsbury; Zhonghui Yang; Tonya M. Ganous; Gary M. Cox; John H. McCusker

2004-01-01

39

A maximum power point tracking for photovoltaic-SPE system using a maximum current controller  

Microsoft Academic Search

Processes to produce hydrogen from solar photovoltaic (PV)-powered water electrolysis using solid polymer electrolysis (SPE) are reported. An alternative control of maximum power point tracking (MPPT) in the PV-SPE system based on the maximum current searching methods has been designed and implemented.Based on the characteristics of voltage–current and theoretical analysis of SPE, it can be shown that the tracking of

Riza Muhida; Mohammed Dakkak; Kenji Matsuura; Akira Tsuyoshi; Masakazu Michira

2003-01-01

40

SPE (tm) water electrolyzers in support of mission from planet Earth  

Microsoft Academic Search

During the 1970's, the Solid Polymer Electrolyte (SPE) water electrolyzer, which uses ion exchange membranes as its sole electrolyte, was developed for nuclear submarine metabolic oxygen production. SPE water electrolyzer developments included operation at up to 3,000 psia and at current densities in excess of 1,000 amps per square foot. The SPE water electrolyzer system has accumulated tens of thousands

J. F. McElroy

1991-01-01

41

Method of making MEA for PEM/SPE fuel cell  

DOEpatents

A method of making a membrane-electrode-assembly (MEA) for a PEM/SPE fuel cell comprising applying a slurry of electrode-forming material directly onto a membrane-electrolyte film. The slurry comprises a liquid vehicle carrying catalyst particles and a binder for the catalyst particles. The membrane-electrolyte is preswollen by contact with the vehicle before the electrode-forming slurry is applied to the membrane-electrolyte. The swollen membrane-electrolyte is constrained against shrinking in the "x" and "y" directions during drying. Following assembly of the fuel cell, the MEA is rehydrated inside the fuel cell such that it swells in the "z" direction for enhanced electrical contact with contiguous electrically conductive components of the fuel cell.

Hulett, Jay S. (West Henrietta, NY)

2000-01-01

42

Solid Polymer Electrolyte (SPE) Fuel Cell Technology, Program Review, Phase 2.  

National Technical Information Service (NTIS)

The purpose of the solid polymer electrolyte (SPE) fuel cell program is to advance the SPE fuel cell technology in four target areas. These areas are: (1) reduced fuel cell costs; (2) reduced fuel cell weight; (3) improved fuel cell efficiency; and (4) in...

1976-01-01

43

Spermidine biosynthesis in Escherichia coli: promoter and termination regions of the speED operon.  

PubMed Central

Two enzymes, S-adenosylmethionine decarboxylase and spermidine synthase, are essential for the biosynthesis of spermidine in Escherichia coli. We have previously shown that the genes encoding these enzymes (speD and speE) form an operon and that the area immediately upstream from the speE gene is necessary for the expression of both the speE and speD genes. We have now studied the upstream promoter and the downstream terminator regions of this operon more completely. We have shown that the major mRNA initiation site (Ia) of the operon is located 475 base pairs (bp) upstream from the speE gene and that there is an open reading frame that encodes for a polypeptide of 115 amino acids between the Ia site and the ATG start codon for the speE gene. Downstream from the stop codon for the speD gene is a potential hairpin structure immediately followed by an mRNA termination site, t. An additional mRNA termination site, t', is present about 110 bp downstream from t and is stronger than t. By comparing our DNA fragments with those prepared from this region of the E. coli chromosome by Kohara et al., we have located the speED operon on the physical map of the E. coli chromosome. We have shown that the orientation of the speED operon is counterclockwise and that the operon is located 137.5 to 140 kbp (2.9 minutes) clockwise from the zero position of the E. coli chromosomal map. Images

Xie, Q W; Tabor, C W; Tabor, H

1989-01-01

44

Novel chimeric spermidine synthase-saccharopine dehydrogenase gene (SPE3-LYS9) in the human pathogen Cryptococcus neoformans.  

PubMed

The Cryptococcus neoformans LYS9 gene (encoding saccharopine dehydrogenase) was cloned and found to be part of an evolutionarily conserved chimera with SPE3 (encoding spermidine synthase). spe3-lys9, spe3-LYS9, and SPE3-lys9 mutants were constructed, and these were auxotrophic for lysine and spermidine, spermidine, and lysine, respectively. Thus, SPE3-LYS9 encodes functional spermidine synthase and saccharopine dehydrogenase gene products. In contrast to Saccharomyces cerevisiae spe3 mutants, the polyamine auxotrophy of C. neoformans spe3-LYS9 mutants was not satisfied by spermine. In vitro phenotypes of spe3-LYS9 mutants included reduced capsule and melanin production and growth rate, while SPE3-lys9 mutants grew slowly at 30 degrees C, were temperature sensitive in rich medium, and died upon lysine starvation. Consistent with the importance of saccharopine dehydrogenase and spermidine synthase in vitro, spe3-lys9 mutants were avirulent and unable to survive in vivo and both functions individually contributed to virulence. SPE3-LYS9 mRNA levels showed little evidence of being influenced by exogenous spermidine or lysine or starvation for spermidine or lysine; thus, any regulation is likely to be posttranscriptional. Expression in S. cerevisiae of the full-length C. neoformans SPE3-LYS9 cDNA complemented a lys9 mutant but not a spe3 mutant. However, expression in S. cerevisiae of a truncated gene product, consisting of only C. neoformans SPE3, complemented a spe3 mutant, suggesting possible modes of regulation. Therefore, we identified and describe a novel chimeric SPE3-LYS9 gene, which may link spermidine and lysine biosynthesis in C. neoformans. PMID:15189996

Kingsbury, Joanne M; Yang, Zhonghui; Ganous, Tonya M; Cox, Gary M; McCusker, John H

2004-06-01

45

The Caenorhabditis elegans spe-39 gene is required for intracellular membrane reorganization during spermatogenesis.  

PubMed Central

Caenorhabditis elegans spermatid formation involves asymmetric partitioning of cytoplasm during the second meiotic division. This process is mediated by specialized ER/Golgi-derived fibrous body-membranous organelles (FB-MOs), which have a fibrous body (FB) composed of bundled major sperm protein filaments and a vesicular membranous organelle (MO). spe-39 mutant spermatocytes complete meiosis but do not usually form spermatids. Ultrastructural examination of spe-39 spermatocytes reveals that MOs are absent, while FBs are disorganized and not surrounded by the membrane envelope usually observed in wild type. Instead, spe-39 spermatocytes contain many small vesicles with internal membranes, suggesting they are related to MOs. The spe-39 gene was identified and it encodes a novel hydrophilic protein. Immunofluorescence with a specific SPE-39 antiserum reveals that it is distributed through much of the cytoplasm and not specifically associated with FB-MOs in spermatocytes and spermatids. The spe-39 gene has orthologs in Drosophila melanogaster and humans but no homolog was identified in the yeast genome. This suggests that the specialized membrane biogenesis steps that occur during C. elegans spermatogenesis are part of a conserved process that requires SPE-39 homologs in other metazoan cell types.

Zhu, Guang-Dan; L'Hernault, Steven W

2003-01-01

46

SPE-39 Family Proteins Interact with the HOPS Complex and Function in Lysosomal Delivery  

PubMed Central

Yeast and animal homotypic fusion and vacuole protein sorting (HOPS) complexes contain conserved subunits, but HOPS-mediated traffic in animals might require additional proteins. Here, we demonstrate that SPE-39 homologues, which are found only in animals, are present in RAB5-, RAB7-, and RAB11-positive endosomes where they play a conserved role in lysosomal delivery and probably function via their interaction with the core HOPS complex. Although Caenorhabditis elegans spe-39 mutants were initially identified as having abnormal vesicular biogenesis during spermatogenesis, we show that these mutants also have disrupted processing of endocytosed proteins in oocytes and coelomocytes. C. elegans SPE-39 interacts in vitro with both VPS33A and VPS33B, whereas RNA interference of VPS33B causes spe-39–like spermatogenesis defects. The human SPE-39 orthologue C14orf133 also interacts with VPS33 homologues and both coimmunoprecipitates and cosediments with other HOPS subunits. SPE-39 knockdown in cultured human cells altered the morphology of syntaxin 7-, syntaxin 8-, and syntaxin 13-positive endosomes. These effects occurred concomitantly with delayed mannose 6-phosphate receptor-mediated cathepsin D delivery and degradation of internalized epidermal growth factor receptors. Our findings establish that SPE-39 proteins are a previously unrecognized regulator of lysosomal delivery and that C. elegans spermatogenesis is an experimental system useful for identifying conserved regulators of metazoan lysosomal biogenesis.

Zhu, Guang-dan; Salazar, Gloria; Zlatic, Stephanie A.; Fiza, Babar; Doucette, Michele M.; Heilman, Craig J.; Levey, Allan I.

2009-01-01

47

IADC/SPE panel probes drilling contracts, business trends  

SciTech Connect

From 1981 to early 1983, more than half the rigs in the U.S. switched from daywork contracts to footage or turnkey drilling. This switch resulted from sudden reversal of the supply/demand picture. It created broad changes in the way operators and drilling contractors do business with each other. It transferred much of the liability and risk to the contractor. It lowered drilling costs. And it caused stunning improvements in rig efficiency. Both operators and contractors are still sorting out the best ways to work under the new order. Their actions on today's challenges will define the future of this marketplace. The form of the contract has been instrumental in changing the nature of drilling. The agreements are changing too. New contracts are more than just a file document mostly for lawyers. They offer a means of communication, a tool for motivation, and a business framework with implications covering business philosophy, profitability, cooperation, and overall results. Four spokesmen from each vantage examined contract trends at the last IADC/SPE Drilling Technology Conference. They hammered out the problems of transition, discussed the long-term future of contracts, and brought forth new proposals beneficial to both parties. Here are the key points from the meeting moderated by Ted Warren, FWA Drilling, and Glen Trimble, Mobil.

Not Available

1983-09-12

48

Development of an SPE/CE method for analyzing HAAs  

USGS Publications Warehouse

The haloacetic acid (HAA) analysis methods approved by the US Environmental Protection Agency involve extraction and derivatization of HAAs (typically to their methyl ester form) and analysis by gas chromatography (GC) with electron capture detection (ECD). Concerns associated with these methods include the time and effort of the derivatization process, use of potentially hazardous chemicals or conditions during methylation, poor recoveries because of low extraction efficiencies for some HAAs or matrix effects from sulfate, and loss of tribromoacetic acid because of decarboxylation. The HAA analysis method introduced here uses solid-phase extraction (SPE) followed by capillary electrophoresis (CE) analysis. The method is accurate, reproducible, sensitive, relatively safe, and easy to perform, and avoids the use of large amounts of solvent for liquid-liquid extraction and the potential hazards and hassles of derivatization. The cost of analyzing HAAs using this method should be lower than the currently approved methods, and utilities with a GC/ECD can perform the analysis in-house.

Zhang, L.; Capel, P. D.; Hozalski, R. M.

2007-01-01

49

Effect of SpeB and EndoS from Streptococcus pyogenes on Human Immunoglobulins  

PubMed Central

Streptococcus pyogenes secretes a specific immunoglobulin G (IgG)-protease, SpeB, as well as the IgG glycan-hydrolyzing enzyme EndoS. Here we show that SpeB also degrades IgA, IgM, IgD, and IgE. We also show that EndoS only hydrolyzes the glycan moiety on native but not denatured IgG. Thus, SpeB has a broad immunoglobulin-degrading activity, while EndoS is highly specific for IgG.

Collin, Mattias; Olsen, Arne

2001-01-01

50

Effect of SpeB and EndoS from Streptococcus pyogenes on human immunoglobulins.  

PubMed

Streptococcus pyogenes secretes a specific immunoglobulin G (IgG)-protease, SpeB, as well as the IgG glycan-hydrolyzing enzyme EndoS. Here we show that SpeB also degrades IgA, IgM, IgD, and IgE. We also show that EndoS only hydrolyzes the glycan moiety on native but not denatured IgG. Thus, SpeB has a broad immunoglobulin-degrading activity, while EndoS is highly specific for IgG. PMID:11598100

Collin, M; Olsén, A

2001-11-01

51

Pre-shot simulations of far-field ground motion for the Source Physics Experiment (SPE) Explosions at the Climax Stock, Nevada National Security Site: SPE2  

SciTech Connect

The Source Physics Experiment (SPE) is planning a 1000 kg (TNT equivalent) shot (SPE2) at the Nevada National Security Site (NNSS) in a granite borehole at a depth (canister centroid) of 45 meters. This shot follows an earlier shot of 100 kg in the same borehole at a depth 60 m. Surrounding the shotpoint is an extensive array of seismic sensors arrayed in 5 radial lines extending out 2 km to the north and east and approximately 10-15 to the south and west. Prior to SPE1, simulations using a finite difference code and a 3D numerical model based on the geologic setting were conducted, which predicted higher amplitudes to the south and east in the alluvium of Yucca Flat along with significant energy on the transverse components caused by scattering within the 3D volume along with some contribution by topographic scattering. Observations from the SPE1 shot largely confirmed these predictions although the ratio of transverse energy relative to the vertical and radial components was in general larger than predicted. A new set of simulations has been conducted for the upcoming SPE2 shot. These include improvements to the velocity model based on SPE1 observations as well as new capabilities added to the simulation code. The most significant is the addition of a new source model within the finite difference code by using the predicted ground velocities from a hydrodynamic code (GEODYN) as driving condition on the boundaries of a cube embedded within WPP which provides a more sophisticated source modeling capability linked directly to source site materials (e.g. granite) and type and size of source. Two sets of SPE2 simulations are conducted, one with a GEODYN source and 3D complex media (no topography node spacing of 5 m) and one with a standard isotropic pre-defined time function (3D complex media with topography, node spacing of 5 m). Results were provided as time series at specific points corresponding to sensor locations for both translational (x,y,z) and rotational components. Estimates of spectral scaling for SPE2 are provided using a modified version of the Mueller-Murphy model. An estimate of expected aftershock probabilities were also provided, based on the methodology of Ford and Walter, [2010].

Mellors, R J; Rodgers, A; Walter, W; Ford, S; Xu, H; Matzel, E; Myers, S; Petersson, N A; Sjogreen, B; Hauk, T; Wagoner, J

2011-10-18

52

WINGS-SPE Spectroscopy in the WIde-field Nearby Galaxy-cluster Survey  

Microsoft Academic Search

Aims: We present the results from a comprehensive spectroscopic survey of the WINGS (WIde-field Nearby Galaxy-cluster Survey) clusters, a program called WINGS-SPE. The WINGS-SPE sample consists of 48 clusters, 22 of which are in the southern sky and 26 in the north. The main goals of this spectroscopic survey are: (1) to study the dynamics and kinematics of the WINGS

A. Cava; D. Bettoni; B. M. Poggianti; W. J. Couch; M. Moles; J. Varela; A. Biviano; M. D'Onofrio; A. Dressler; G. Fasano; J. Fritz; P. Kjærgaard; M. Ramella; T. Valentinuzzi

2009-01-01

53

WINGS-SPE Spectroscopy in the WIde-field Nearby Galaxy-cluster Surve y  

Microsoft Academic Search

Aims. We present the results from a comprehensive spectroscopic survey of the WINGS (WIde-field Nearby Galaxy-cluster Survey ) clusters, a program called WINGS-SPE. The WINGS-SPE sampleconsists of 48 clusters, 22 of which are in the southern sky and 26 in the north. The main goals of this spectroscopic survey are: (1) to study the dynamics and kinematics of the WINGS

A. Cava; D. Bettoni; B. M. Poggianti; W. J. Couch; M. Moles; J. Varela; A. Biviano; M. D'Onofrio; A. Dressler; G. Fasano; J. Fritz; P. Kjærgaard; M. Ramella; T. Valentinuzzi

54

Spark plasma extrusion (SPE) of ball-milled aluminum and carbon nanotube reinforced aluminum composite powders  

Microsoft Academic Search

Ball-milled aluminum (Al) and Al–carbon nanotube (CNT) composite (2.5wt.% CNT loading) powders have been consolidated using a spark plasma extrusion (SPE) process. Compared with spark plasma sintering (SPS), SPE has the added advantages of allowing the production of powder-based materials of extended geometries and bulk deformation under the influence of electric current which may yield materials with unique properties. The

K. Morsi; A. M. K. Esawi; S. Lanka; A. Sayed; M. Taher

2010-01-01

55

Determination of ethyl glucuronide in human hair by SPE and LC–MS\\/MS  

Microsoft Academic Search

A method for the sensitive and selective determination of ethyl glucuronide (EtG) in hair has been developed using solid-phase extraction (SPE) and liquid chromatography–tandem mass spectrometry (LC–MS\\/MS). Washed and cut hair segments were extracted by ultrasonication (3h, 50°C) and the extracts were cleaned-up with aminopropyl SPE columns. LC–MS\\/MS analysis was performed using a polar-endcapped phenyl-hexyl-RP-phase with negative mode electrospray ionisation

Ines Janda; Wolfgang Weinmann; Thorsten Kuehnle; Martina Lahode; Andreas Alt

2002-01-01

56

SPE–GC\\/FTD determination of N-methyl-2-pyrrolidone and its metabolites in urine  

Microsoft Academic Search

An analytical method using a combination of solid-phase extraction (SPE) and gas chromatography with a flame thermionic detector (GC\\/FTD) was developed for determination of N-methyl-2-pyrrolidone (NMP), N-methylsuccinimide (MSI), and 2-hydroxy-N-methylsuccinimide (2-HMSI) in human urine. The SPE cartridge of poly(divinylbenzene\\/hydroxymethacrylate) used was directly loaded with urine sample, followed by elution with methyl isobutyl ketone (MIBK) and subsequent centrifugation, and the supernatant

Ryuichi Kubota; Yoko Endo; Akito Takeuchi; Yoshinori Inoue; Hiroko Ogata; Masanori Ogawa; Tomoo Nakagawa; Nobuhiko Onda; Ginji Endo

2007-01-01

57

New SPE column packing material: Retention assessment method and its application for the radionuclide chromatographic separation  

Microsoft Academic Search

a  The preparation of the OASIS®-HLB sorbent based solid phase extraction (SPE) resins and their application for the 177Lu radioisotope separation were investigated. Di-(2-ethylhexyl) orthophosphoric acid (HDEHP) impregnated OASIS-HLB sorbent\\u000a based SPE resins (OASIS-HDEHP) were successfully developed from this investigation. The wettable porosity structure of the\\u000a moderately extractant impregnated OASIS-HDEHP resins is favorable for the effective diffusion of polar and ionic

Le Van So; N. Morcos

2008-01-01

58

The M Protein Is Dispensable for Maturation of Streptococcal Cysteine Protease SpeB  

PubMed Central

The streptococcal pyrogenic exotoxin B (SpeB) is an important virulence factor of group A streptococci (GAS) with cysteine protease activity. Maturation of SpeB to a proteolytically active form was suggested to be dependent on cell-wall-anchored M1 protein, the major surface protein of GAS (M. Collin and A. Olsén, Mol. Microbiol. 36:1306-1318, 2000). Collin and Olsén showed that mutant GAS strains expressing truncated M protein secrete a conformationally different form of unprocessed SpeB with no proteolytic activity. Alternatively, we hypothesized that a truncated M protein may interfere with processing of this secreted protease, and therefore we tested cysteine protease activity in genetically defined mutant strains that express either no M protein or membrane-anchored M protein with an in-frame deletion of the AB repeat region. Measurements of SpeB activity by cleavage of a substrate n-benzoyl-Pro-Phe-Arg-p-nitroanilide hydrochloride showed that the proteolytic activities in culture supernatants of both mutants were similar to those from the wild-type strain. In addition, Western blot analysis of culture supernatants showed that SpeB expression and processing to a mature form was unaffected by either deletion mutation. Therefore, we conclude that M protein is not required for maturation of the streptococcal cysteine protease SpeB.

Zimmerlein, Bjorn; Park, Hae-Sun; Li, Shaoying; Podbielski, Andreas; Cleary, P. Patrick

2005-01-01

59

Epidermal Langerhans Cell Depletion After Artificial Ultraviolet B Irradiation of Human Skin In Vivo: Apoptosis Versus Migration  

Microsoft Academic Search

Ultraviolet B radiation can suppress cellular immunity. One of the mechanisms related to this immunosuppression is the disappearance of Langerhans cells from the epidermis. The aim of this study was to establish the mechanism of ultraviolet B-induced Langerhans cell disappearance in healthy individuals. The two most likely mechanisms for Langerhans cell disappearance are apoptosis and migration. Apoptosis was assessed in

Wendy Kölgen; Hilde Both; Huib van Weelden; Kees L. H. Guikers; Carla A. F. M. Bruijnzeel-Koomen; Edward F. Knol; Willem A. van Vloten; Frank R. de Gruijl

2002-01-01

60

Spacecraft Solar Particle Event (SPE) Shielding: Shielding Effectiveness as a Function of SPE Model as Determined with the FLUKA Radiation Transport Code  

Microsoft Academic Search

In the this paper, we report the results of modeling and simulation studies in which the radiation transport code FLUKA (FLUktuierende KAskade) is used to determine the changes in total ionizing dose (TID) and single-event effect (SEE) environments behind aluminum, polyethylene, carbon, and titanium shielding masses when the assumed form (i.e., Band or Exponential) of the solar particle event (SPE)

S. L. Koontz; W. A. Atwell; B. Reddell; K. Rojdev

2010-01-01

61

Tubifex: a sensitive model for UV-B-induced phototoxicity.  

PubMed

The natural increase of UV-B radiation levels due to depletion of the ozone layer in the atmosphere may impose additional stress for the survival of zooplanktons which serve as a major constituent of the aquatic food chain. To study the adverse effects of UV-B radiation on the aquatic biomass, studies were conducted using the aquatic organism Tubifex as a model, as UV-B radiation is known to penetrate into the natural waters. UV-B radiation induced mortality in tubifex and the production of activated oxygen species by these organisms. Alterations in DNA, RNA, protein, glutathione (GSH), hydrogen peroxide H(2)O(2), thiobarbituric acid-reactive substance (TBA-RS), ATPase, AChE, GST, and LDH activities in Tubifex at various doses (0-2.0 J) of UV-B radiation were found. LC(50) value for UV-B-induced mortality of Tubifex was 0.80+/-0.15 J and the threshold dose was 0.35+/-0.05 J; mortality began within 3h postirradiation. UV-B dose-dependent production of singlet oxygen, superoxide anion, and hydroxyl radicals by Tubifex was observed. DNA, RNA, protein, and GSH contents were found to decrease significantly (P<0.001) while H(2)O(2) and TBA-RS increased (P<0.01) under the influence of UV-B radiation. The activities of ATpase, AChE, and GST enzymes were inhibited (P<0.01) and LDH activity was significantly increased (P<0.001) in Tubifex exposed to UV-B radiation. The results suggest that an increase in UV-B radiation alters several biochemical processes, leading to the mortality of the organism. Tubifex could be useful as a sensitive alternate model for studying UV-B-induced phototoxicity and possible mechanisms of action. PMID:12297092

Misra, R B; Babu, G Suresh; Ray, R S; Hans, R K

2002-07-01

62

The Transurethral Suprapubic endo-Cystostomy (T-SPeC): A Novel Suprapubic Catheter Insertion Device  

PubMed Central

Abstract Background and Purpose Current methods of suprapubic cystostomy (SPC) catheter insertion may be difficult for patients in poor health and can result in significant morbidity and mortality. These include a highly invasive open procedure, as well as the use of the percutaneous trocar punch methods, commonly associated with short-term SPC. We present the first human experience with the Transurethral Suprapubic endo-Cystostomy (T-SPeC®) device, a novel disposable device used for introducing a suprapubic catheter via a retrourethral (inside-to-out) approach similar to the Lowsley technique. Patients and Methods Four men at St. Mary's General Hospital in Kitchener Ontario, Canada, received the T-SPeC device (model T7) under general anesthesia. Results Patients had no complications from catheterization using the T-SPeC T7 Surgical System. The mean surgical time of the four procedures was 9.7 minutes, with a range of 7.9 to 13.5 minutes, including instrument preparation and cystoscopy. All four procedures were highly accurate and rapid. There were no complications and minimal blood loss from the procedure. Conclusions We found that the T-SPeC device allows for efficient and safe insertion of a suprapubic catheter in an outpatient setting and may be a useful addition to the urologic armamentarium. The T-SPeC Surgical System facilitates rapid and precise suprapubic catheter placement.

Egerdie, R. Blair; Albala, David M.; Flynn, Brian J.

2013-01-01

63

Selective determination of potential impurities in an active pharmaceutical ingredient using HPLC-SPE-HPLC.  

PubMed

The present paper describes the selective determination of two synthetic intermediates (2,4-dichloro-6,7-dimethoxyquinazoline (IMP-1) and its derivative (IMP-2) as potential impurities in the active pharmaceutical ingredient (API)-A using two-dimensional high-performance liquid chromatography (HPLC) hyphenated via on-line solid-phase extraction (SPE) (HPLC-SPE-HPLC). Two synthetic intermediates that are potential impurities in API-A were concentrated on-line on two Shimadzu MAYI-ODS SPE columns (10 mm×4.6 mm I.D.) after heartcutting in 1st dimension HPLC (1st HPLC) using a Shiseido CAPCELL PAK ACR C18 column (250 mm × 10.0 mm I.D.). Each analyte retained on these SPE columns was transferred to 2nd dimension HPLC (2nd HPLC) with a Shiseido CAPCELL PAK MG-II column (150 mm × 3.0 mm I.D.) for further separation and was subsequently detected with high sensitivity UV. The HPLC-SPE-HPLC system achieved a stepwise downsizing in HPLC. The method was validated and found to be accurate and precise with a linear range of 0.25-250 ppm of each intermediate in API-A with respect to a 500 ?L injection of 40 mg/mL of API-A in dimethyl sulfoxide. The method was successfully applied for the determination of these impurities in API batches, and the results demonstrated the usefulness of HPLC-SPE-HPLC for the selective determination of trace impurities in APIs. PMID:23806999

Yamamoto, Eiichi; Niijima, Jun; Asakawa, Naoki

2013-06-13

64

On-line coupling of SPE and CE-MS for peptide analysis.  

PubMed

An on-line SPE-CE-MS system has been developed for the analysis of peptides. Analytes are preconcentrated using a C(18) microcolumn (5 x 0.5 mm id), and then introduced into the CE system via a valve interface. The CE system with a Polybrene-poly(vinylsulfonate) bilayer coated capillary is combined with an ion-trap mass spectrometer via ESI using a coaxial sheath-liquid sprayer. The on-line coupling of the SPE and CE step by the valve interface is advantageous because it allows an independent functioning of the system parts. Optimization of the SPE-CE system was performed using UV detection. Subsequently, the SPE-CE system has been coupled to the ion-trap mass spectrometer. Test solutions with enkephalin peptides (50 ng/mL) were used for evaluation of system performance. Repeatability of effective mobility and peak area ratio of the two enkephalins were within 1.2% and 9% RSD, respectively. The analysis of 1:1 v/v diluted cerebrospinal fluid samples spiked with enkephalin peptides showed detection limits (S/N = 3) in the range of 1.5-3 ng/mL (around 5 nM), which were similar to those obtained for enkephalin test solutions. Moreover, the potential of the on-line SPE-CE-MS system was demonstrated by the analysis of a cytochrome C digest. Some hydrophilic peptides did not show sufficient retention on the SPE column, and were lost during preconcentration. Nonetheless, positive identification of the protein was achieved, indicating the feasibility of the system for proteomics. PMID:17351891

Tempels, F W Alexander; Underberg, Willy J M; Somsen, Govert W; de Jong, Gerhardus J

2007-05-01

65

Lysosomes as a possible target of enniatin B-induced toxicity in Caco-2 cells.  

PubMed

Enniatins are cyclic hexadepsipeptidic mycotoxins with ionophoric, antibiotic, and insecticidal activity. Enniatin B (EnnB), the most important analogue, is produced by many Fusarium species and is a common contaminant in grain-based foods. The compound's cytotoxic potential has been shown in different experiments; however, the mode of action has not been detailed so far. In the present study, several mutually confirmative experiments have been performed indicating that EnnB-initiated cytotoxicity could be connected with lysosomal membrane permeabilization (LMP). Lysosomal functionality, as assessed by the Neutral Red assay, was already affected after 3 h of toxin exposure. After 24 h, cell proliferation was decreased, and there was indication for a cell cycle arrest in the G(2)/M phase leading to the initiation of apoptosis or necrosis. Intracellular ROS-production was observed. However, antioxidants did not alter the observed EnnB-induced loss of lysosomal functionality leading to the conclusion that ROS was not an initial factor but one produced later in the event cascade. The collected data suggested that lysosomal destabilization is an upstream event in EnnB-initiated cytotoxicity followed by a certain extent of translocation of cathepsins into the cytosol, which was observed using immunological and proteomic methods. It appeared that cell death induced by EnnB was delayed and occurred not as a massive lysosomal breakdown but was probably progressing and leading to partial and selective LMP, starting a nonapoptotic cell death pathway with morphological features that had been previously considered as necrotic. The molecular mechanism of EnnB-triggered lysosomal destabilization, and the cellular processes leading to mitochondrial permeabilization and cell death are still unknown. They may, however, be connected to the compound's ionophoric properties. PMID:22731695

Ivanova, L; Egge-Jacobsen, W M; Solhaug, A; Thoen, E; Fæste, C K

2012-07-19

66

Photovoltaic-powered solid polymer electrolyte (SPE) electrolyzer system evaluation. Final report  

SciTech Connect

The final results of the evaluation of a photovoltaic-powered solid polymer electrolyte (SPE) electrolyzer system at the Brookhaven National Laboratory (BNL) Hydrogen Technology Evaluation Center (HTEC) are presented. The HTEC facility and the SPE electrolyzer system are described. Electrolyzer test results are then presented. A technoeconomic analysis of hydrogen production via PV-powered electrolysis and other options is reported. The use of grid versus photovoltaic electricity is evaluated parametrically. PV-electrolyzer system transient computer results are presented. The economic model on which the technoeconomic analysis is based is appended, as well as fitting equations and coefficients of some of the test results. (LEW)

Metz, P.D.; Piraino, M.

1985-07-01

67

Cytochrome P-450-catalyzed reactive oxygen species production mediates the (-)schisandrin B-induced glutathione and heat shock responses in H9c2 cardiomyocytes  

PubMed Central

Objective: Schisandrin B (Sch B) is the most abundant, active dibenzocyclooctadiene derivative isolated from the fruit of Schisandra chinensis (Turcz) Baillon (Schisandraceae). (–)Sch B was found to be the most potent stereoisomer of Sch B in producing cytoprotective action in H9c2 cardiomyocytes. The elucidation of biochemical mechanism underlying the cytoprotection of (–)Sch B has attracted much interest in the area of preventive medicine. Here, we examined whether the (–)Sch B-induced enhancement of glutathione antioxidant and heat shock responses and the associated cytoprotection against hypoxia/reoxygenation-induced apoptosis are mediated by reactive oxygen species (ROS) arising from cytochrome P-450 (CYP)-catalyzed metabolism of (–)Sch B in H9c2 cardiomyocytes. Materials and Methods: The effects of CYP inhibitor (1-aminobenzotriazole, ABT) and antioxidant (dimethylthiouracil, DMTU) on (–)Sch B-induced ROS production and associated increases in cellular-reduced glutathione (GSH) level as well as heat shock protein (Hsp) 25/70 production were investigated in H9c2 cardiomyocytes. The (–)Sch B-induced ROS generation was monitored with or without ABT/DMTU for 6 h in situ, while (–)Sch B-induced cellular GSH level and Hsp 25/70 production, as well as cytoprotection were measured at 16 h post-(–)Sch B exposure. Results: The results indicated that (–)Sch B caused a dose-dependent increase in ROS production in H9c2 cardiomyocytes, which was completely suppressed by pre- and co-treatment with ABT or DTMU. The incubation with (–)Sch B for 6 h caused dose-dependent increases in cellular GSH level and Hsp 25/70 production, as well as protection against hypoxia/reoxygenation-induced apoptosis at 16-h post-drug exposure in H9c2 cardiomyocytes. All these cellular responses were abrogated by treatment with ABT or DMTU. Conclusion: The results suggest that ROS arising from the CYP-catalyzed metabolism of (–)Sch B elicit glutathione antioxidant and heat shock responses, thereby protecting against oxidant-induced apoptosis in H9c2 cardiomyocytes.

Chen, Na; Chiu, Po Yee; Leung, Hoi Yan; Ko, Kam Ming

2012-01-01

68

MULTI-SPE OF CAFFEINE AND CATECHIN COMPOUNDS FROM GREEN TEA BY CAFFEINE AND (+) CATECHIN MIPS  

Microsoft Academic Search

In this work, the caffeine and some catechin compounds (+) C, EC, and EGCG were extracted from green tea by using two molecular imprinted polymers (MIPs) as sorbent materials in a multi-solid-phase extraction (SPE) process known as MISPE (molecular imprinted solid-phase extraction). To obtain synthesis of MIP, (+) catechin (and caffeine) was employed as the template, AM (and MAA) as

Yinzhe Jin; Yong-Hao Xuan; Ying-Shan Jin; Kyung Ho Row

2011-01-01

69

Electrochemical treatment of aqueous oxalic acid solution by using solid polymer electrolyte (SPE) reactor  

Microsoft Academic Search

In this study, the feasibility of electrochemical oxidation of the aqueous oxalic acid solution has been investigated in an electrochemical reactor with SPE and simultaneous hydrogen production has been observed.Experiments were conducted to examine the effects of applied current density, flow rate of solution, pH of the solution, the concentration of supporting electrolyte, the temperature of the solution, types of

Ebru Önder; Ali Sava? Koparal; Ülker Bakir Ö?ütveren

2009-01-01

70

The sensibility of SPE induced atmospheric photochemical response to the ionization rate variations.  

NASA Astrophysics Data System (ADS)

During Solar proton event (SPE) energetic particles affect neutral atmospheric chemistry (Jackman et al. 1990, Krivolutsky A.A. et al. 2001 ets. ). The calculations results for [NO] and [O3] changes have qualitative suitability with observations data from satellites (UARS, HALOE for N.P.), although the simulated result differs in value from observed ones for nitrogen compounds. It seems potential probable reasons for this diversity exist. The sensibility of SPE induced atmospheric response to the ionization rates was investigated. The solar proton fluxes data from two satellites were used for ionization rate calculations by the method Vitt and Jackman (1996): geo-stationary GOES-10 (orbit height ? 40000 km) and CORONAS (orbit height is ? 400 km) for period of SPE 28.10. 2003. Calculated time integral ion creation during SPE using low and high orbit data differs for 1.5. Differences in ionization rate vertical distribution from GOES and CORONAS were found. Using this different ionization data the atmospherical composition response has been simulated with 1D photochemical model. The corresponding differences are discussed.

Krivolutsky, Alexei A.; Kukoleva, Anna; Kuminov, Alexander; Maygkova, Irina

71

LC-SPE-NMR Identification of Co-products from Biomass  

Technology Transfer Automated Retrieval System (TEKTRAN)

The hyphenated technique of LC-SPE-NMR was utilized to isolate and identify cinnamic acids and investigate their derivatives from the chloroform extract from Coastal bermudagrass. This method has shown to be useful in handling impure mixtures of extractants from biomass material. It overcomes the ...

72

WINGS-SPE Spectroscopy in the WIde-field Nearby Galaxy-cluster Survey  

NASA Astrophysics Data System (ADS)

Aims: We present the results from a comprehensive spectroscopic survey of the WINGS (WIde-field Nearby Galaxy-cluster Survey) clusters, a program called WINGS-SPE. The WINGS-SPE sample consists of 48 clusters, 22 of which are in the southern sky and 26 in the north. The main goals of this spectroscopic survey are: (1) to study the dynamics and kinematics of the WINGS clusters and their constituent galaxies, (2) to explore the link between the spectral properties and the morphological evolution in different density environments and across a wide range of cluster X-ray luminosities and optical properties. Methods: Using multi-object fiber-fed spectrographs, we observed our sample of WINGS cluster galaxies at an intermediate resolution of 6-9 Å and, using a cross-correlation technique, we measured redshifts with a mean accuracy of ~45 km s-1. Results: We present redshift measurements for 6137 galaxies and their first analyses. Details of the spectroscopic observations are reported. The WINGS-SPE has ~30% overlap with previously published data sets, allowing us both to perform a complete comparison with the literature and to extend the catalogs. Conclusions: Using our redshifts, we calculate the velocity dispersion for all the clusters in the WINGS-SPE sample. We almost triple the number of member galaxies known in each cluster with respect to previous works. We also investigate the X-ray luminosity vs. velocity dispersion relation for our WINGS-SPE clusters, and find it to be consistent with the form Lx ? ?_v^4. Table 4, containing the complete redshift catalog, is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/495/707

Cava, A.; Bettoni, D.; Poggianti, B. M.; Couch, W. J.; Moles, M.; Varela, J.; Biviano, A.; D'Onofrio, M.; Dressler, A.; Fasano, G.; Fritz, J.; Kjærgaard, P.; Ramella, M.; Valentinuzzi, T.

2009-03-01

73

Influence of cyclic AMP, agmatine, and a novel protein encoded by a flanking gene on speB (agmatine ureohydrolase) in Escherichia coli.  

PubMed Central

The speB gene of Escherichia coli encodes agmatine ureohydrolase (AUH), a putrescine biosynthetic enzyme. The speB gene is transcribed either from its own promoter or as a polycistronic message from the promoter of the speA gene encoding arginine decarboxylase. Two open reading frames (ORF1 and ORF2) are present on the strand complementary to speB; approximately 90% of ORF2 overlaps the speB coding region. Analysis of transcriptional and translational fusions of ORF1 or ORF2 to lacZ revealed that ORF1 encoded a novel protein while ORF2 was not transcribed. Deletion of ORF1 from a plasmid containing ORF1, ORF2, and speB reduced the activity of AUH by 83%. In contrast, the presence of plasmid-encoded ORF1 caused an 86% increase in chromosomally encoded AUH activity. ORF1 did not stimulate alkaline phosphatase expressed from a phi(speB-phoA) transcriptional fusion encoded on the same plasmid. Western analysis (immunoblot) of a phi(ORF1-lacZ) translational fusion revealed that ORF1 encodes a 25.3-kDa protein. Agmatine induced transcription of phi(speB-phoA) but not phi(speA-phoA) fusions. Consequently, agmatine affects selection between the monocistronic and the polycistronic modes of speB transcription. In contrast, cyclic AMP (cAMP) repressed AUH activity of chromosomally encoded AUH but had no effect on plasmid-borne speB nor phi(speB-phoA). It is concluded that ORF1 encodes a protein which is a posttranscriptional regulator of speB, agmatine induces speB independent of speA, and cAMP regulates speB indirectly. Images

Szumanski, M B; Boyle, S M

1992-01-01

74

EndoS and SpeB from Streptococcus pyogenes Inhibit Immunoglobulin-Mediated Opsonophagocytosis  

PubMed Central

The human pathogen Streptococcus pyogenes primarily infects the upper respiratory tract and skin, but occasionally it disseminates and causes severe invasive disease with high mortality. This study revealed that the activity of extracellular EndoS, which hydrolyzes the functionally important N-linked oligosaccharides on opsonizing immunoglobulin G (IgG), contributes to increased survival of S. pyogenes in human blood ex vivo. The inability to kill the bacteria is due to reduced binding of IgG to Fc receptors and impaired classical pathway-mediated activation of complement. In addition, the activity of extracellular SpeB, which cleaves IgG into Fc and Fab fragments, also increases bacterial survival. This suggests that S. pyogenes expresses two enzymes, EndoS and SpeB, which modulate IgG by different mechanisms in order to evade the adaptive immune system.

Collin, Mattias; Svensson, Mikael D.; Sjoholm, Anders G.; Jensenius, Jens C.; Sjobring, Ulf; Olsen, Arne

2002-01-01

75

First Results From an IRTF Near-Infrared SPeX Debris Disk Spectral Survey  

NASA Astrophysics Data System (ADS)

Over the last 3 years we have conducted a focused SPeX study of nearby AFGK exosystems with strong IRAS/Spitzer mid-IR fluxes and < 1 Gyr ages. Objects were observed from 0.8 - 5.2 um using R=1000 to 2000 spectroscopy. Our observational goal is to characterize the primary star and determine the amount of scattered light, thermal emission, and line emission due to orbiting circumstellar material. The ultimate scientific goal is to characterize the circumstellar material and find evidence for material created by impacts, collisional grinding, and/or sublimation of bodies in these planet building systems. Our observations take advantage of and add to the SPeX spectral library of ~200 cool FGKM stars (Rayner et al. 2009). In this talk we report the preliminary findings of our survey of 20+ systems.

Lisse, Carey M.; Sitko, M. L.; Christian, D. J.; Melis, C.; Chen, C.

2013-01-01

76

EndoS and SpeB from Streptococcus pyogenes inhibit immunoglobulin-mediated opsonophagocytosis.  

PubMed

The human pathogen Streptococcus pyogenes primarily infects the upper respiratory tract and skin, but occasionally it disseminates and causes severe invasive disease with high mortality. This study revealed that the activity of extracellular EndoS, which hydrolyzes the functionally important N-linked oligosaccharides on opsonizing immunoglobulin G (IgG), contributes to increased survival of S. pyogenes in human blood ex vivo. The inability to kill the bacteria is due to reduced binding of IgG to Fc receptors and impaired classical pathway-mediated activation of complement. In addition, the activity of extracellular SpeB, which cleaves IgG into Fc and Fab fragments, also increases bacterial survival. This suggests that S. pyogenes expresses two enzymes, EndoS and SpeB, which modulate IgG by different mechanisms in order to evade the adaptive immune system. PMID:12438337

Collin, Mattias; Svensson, Mikael D; Sjöholm, Anders G; Jensenius, Jens C; Sjöbring, Ulf; Olsén, Arne

2002-12-01

77

Cloning of the gene, speB, for streptococcal pyrogenic exotoxin type B in Escherichia coli.  

PubMed Central

The structural gene encoding streptococcal pyrogenic exotoxin type B, designated speB, was cloned in Escherichia coli and localized onto a 4.5-kilobase BamHI-BglII DNA fragment. Streptococcal pyrogenic exotoxin type B, partially purified from E. coli clones, was immunologically related to streptococcus-derived toxin. Also, toxin derived from either E. coli or Streptococcus pyogenes had similar lymphocyte mitogenic activity and molecular weight (29,300) and displayed comparable microheterogeneity when evaluated by isoelectric focusing. Images

Bohach, G A; Hauser, A R; Schlievert, P M

1988-01-01

78

Analytical development for analysis of pharmaceuticals in water samples by SPE and GC–MS  

Microsoft Academic Search

An analytical procedure involving solid-phase extraction (SPE) and gas chromatography–mass spectrometry (GC–MS) has been developed\\u000a for determination of pharmaceutical compounds (aspirin, caffeine, carbamazepine, diclofenac, ketoprofen, naproxen, ibuprofen,\\u000a clofibrate, clofibric acid, and gemfibrozil) in a variety of aqueous samples (wastewater and surface water). After filtration,\\u000a samples were extracted and concentrated using C18 or HLB cartridges, depending on the type of compound.

Anne Togola; Hélène Budzinski

2007-01-01

79

Determination of antibiotic compounds in water by on-line SPE-LC\\/MSD  

Microsoft Academic Search

This study attempts to provide an improved approach for the analysis of antibiotics, which normally exist at low concentration in complex matrices such as receiving streams of wastewater treatment plant discharge. The analytical method developed in this study combines an existing pretreatment technique of solid-phase extraction (SPE) with liquid chromatography mass spectrometry (LC\\/MSD) through on-line connection. The on-line connection suppressed

Keun-Joo Choi; Sang-Goo Kim; Chang-won Kim; Seung-Hyun Kim

2007-01-01

80

Identification of Radical Scavenging Compounds in Rhaponticum carthamoides by Means of LC-DAD-SPE-NMR  

Microsoft Academic Search

A hyphenated LC-DAD-SPE-NMR setup in combination with on-line radical scavenging detection has been applied for the identification of radical scavenging compounds in extracts of Rhaponticum carthamoides. After NMR measurements, the pure compounds were infused into a mass spectrometer. The technique enabled selective detection and identification of individual radical scavenging compounds without any prior off-line chromatographic steps. Seven compounds, namely, quercetagetin-7--glucopyranoside

Giedrius Miliauskas; Beek van T. A; Pieter de Waard; Rimantas P. Venskutonis; Ernst J. R. Sudhölter

2005-01-01

81

Simulation of the SPE4 small-break loss-of-coolant accident  

Microsoft Academic Search

A small-break loss of coolant accident (SBLOCA) conducted at the PMK-2 integral test facility was analyzed using RELAP5\\/MOD3. 1. The experiment simulated a 7.4% break in the cold leg of a VVER-440\\/213-type nuclear power plant as part of the International Atomic Energy Agency's Fourth Standard Problem Exercise (SPE-4). The VVER design differs from pressurized water reactors (PWRS) of western origin,

P. Cebull; Y. A. Hassan

1993-01-01

82

A New Method of Facial Expression Recognition Based on SPE Plus SVM  

NASA Astrophysics Data System (ADS)

A novel method of facial expression recognition (FER) is presented, which uses stochastic proximity embedding (SPE) for data dimension reduction, and support vector machine (SVM) for expression classification. The proposed algorithm is applied to Japanese Female Facial Expression (JAFFE) database for FER, better performance is obtained compared with some traditional algorithms, such as PCA and LDA etc.. The result have further proved the effectiveness of the proposed algorithm.

Ying, Zilu; Huang, Mingwei; Wang, Zhen; Wang, Zhewei

83

Modeling Saturn's 5-micron IRTF/SpeX and Cassini/VIMS Spectra  

NASA Astrophysics Data System (ADS)

Cassini's Visual Infrared Mapping Spectrometer (VIMS) is revealing dramatic structure in the clouds of Saturn's atmosphere. We complement VIMS observations by simultaneously making ground-based observations around 5 microns using the SpeX spectrograph on NASA's Infrared Telescope Facility (IRTF). Compared to VIMS, SpeX has higher spectral resolution but lower spatial resolution. Saturn's 5-micron flux from the day side is divided into two roughly equal components: reflected sunlight and thermal emission from the deep atmosphere. The exact ratio of these components varies spatially on Saturn due to its cloud structure. VIMS can separate the components by observing not only Saturn's day side, but also its night side, where by definition the reflected sunlight component is zero. Near 5 microns, we specifically concentrate on phosphine and ammonia absorption. We model Saturn's spectra using the SSP code at NASA/GSFC, which accounts for volume mixing ratio vs pressure profiles of atmospheric species and cloud height and thickness. We start by modeling the thermal component of VIMS night-side data at various northern and southern latitudes and then model VIMS day-side data and SpeX data by adding the reflected sunlight component, also at various latitudes. Observing Saturn's northern hemisphere from the IRTF is becoming easier as Saturn approaches its equinox in 2009. Our modeling efforts will enable us to characterize latitudinal variations in the spectra around 5 microns. The rich data sets provided by Cassini/VIMS and IRTF/SpeX can provide us with many insights into atmospheric abundances, chemistry, transport, and energy balance. This project is supported by a scholarship from the U.S. Air Force and grants from the National Science Foundation (AST-0507558) and NASA (NNG06G126G).

Carlson, Randall E.; Chanover, N.; Bjoraker, G.; Momary, T.; Baines, K. H.; Hewagama, T.; Glenar, D.

2008-09-01

84

Retention behaviour of some high-intensity sweeteners on different SPE sorbents  

Microsoft Academic Search

The objective of this paper is to provide information about application of solid-phase extraction (SPE) for isolation of nine high-intensity sweeteners (acesulfame-K, alitame, aspartame, cyclamate, dulcin, neotame, saccharin, sucralose and neohesperidin dihydrochalcone) from aqueous solutions. The influence of several types of LC–MS compatible buffers (different pH values and compositions) on their recovery has been studied and discussed. A number of

Agata Zygler; Andrzej Wasik; Jacek Namie?nik

2010-01-01

85

SPE analysis of high efficiency PMTs for the DEAP-3600 dark matter detector  

NASA Astrophysics Data System (ADS)

The Dark matter Experiment using Argon Pulse-shape discrimination is a collaborative effort to develop a next-generation, tonne-scale dark matter detector at SNOLAB. The detector will feature a single-phase liquid argon (LAr) target surrounded by an array of 266 photomultiplier tubes (PMTs). A new high-efficiency Hamamatsu R877-100 PMT has been delivered to the University of Alberta for evaluation by the DEAP collaboration. The increase in efficiency could lead to a much greater light yield, but other experiments have reported a slower rise time [1],[2]. We have placed the PMT in a small dark box and had a base and preamplifier designed to be used with either an oscilloscope or a multi-channel analyzer. With this setup we have demonstrated the PMT's ability to distinguish single photo-electrons (SPE) and characterized the PMT by measuring the SPE pulse height spectrum, the peak-to-valley ratio, the dark pulse rate, the baseline, time resolution and SPE efficiency for varying the high voltage supplied to the PMT.

Olsen, Kevin; Hallin, Aksel; DEAP/CLEAN Collaboration

2011-09-01

86

Overview of passive Chemcatcher sampling with SPE pretreatment suitable for the analysis of NPEOs and NPs.  

PubMed

The European Union Water Framework Directive (WFD; 2000/60/EC) is an important piece of environmental legislation that protects rivers, lakes, coastal waters and groundwaters (EC 2000). The implementation of the WFD requires the establishment and use of novel and low-cost monitoring programmes, and several methods, e.g. passive sampling, have been developed to make the sampling process more representative compared to spot sampling. This review considers passive sampling methods focusing mainly on a passive sampler named Chemcatcher®, which has been used for monitoring several harmful compounds in aquatic environments. Also, the sample treatment and analysis of nonylphenol ethoxylates (NPEOs) and nonylphenol (NPs) from water using solid phase extraction (SPE) is briefly summarized. The procedure of Chemcatcher passive sampling is quite similar to that of the SPE extraction since it concentrates the studied compounds from water as well. After sampling, the accumulated substances are extracted from the receiving phase of the sampler. The concentrations of NPEOs and NPs are currently monitored by taking conventional spot samples; SPE can be successfully used as a pretreatment procedure. Chemcatcher® passive sampling technique is a simple and useful monitoring tool and can be applied to new chemicals, such as NPEOs and NPs in aquatic environments. PMID:22983602

Ahkola, Heidi; Herve, Sirpa; Knuutinen, Juha

2012-09-15

87

Targeted natural product isolation guided by HPLC-SPE-NMR: constituents of Hubertia species.  

PubMed

The hyphenated technique, high-performance liquid chromatography-solid-phase extraction-nuclear magnetic resonance spectroscopy (HPLC-SPE-NMR), has been applied for rapid identification of novel natural products in crude extracts of Hubertia ambavilla and Hubertia tomentosa. The technique allowed full or partial identification of all major extract constituents and demonstrated the presence of unusual quinic acid derivatives containing the (1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetyl residue that exhibit strongly coupled ABXY patterns, the parameters of which were obtained by spin simulations. Using homo- and heteronuclear 2D NMR data acquired in the HPLC-SPE-NMR mode, complete structure determination of three new natural products, i.e., 3,5-di-O-caffeoyl-4-O-[(1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetyl]quinic acid (1), its 2-hydroxy derivative (2), and 3,5-di-O-caffeoyl-4-O-[(4-hydroxyphenyl)acetyl]quinic acid (3), was performed. Finally, targeted isolation of 1 was achieved by SPE fractionation and preparative HPLC, followed by evaluation of its antioxidant and antimicrobial activity. In contrast to chlorogenic acid and 3,5-di-O-caffeoylquinic acid, which act as antioxidants, compound 1 proved at the same conditions to possess prooxidant activity in an assay evaluating the oxidation of human low-density lipoprotein induced by Cu(2+). PMID:17822297

Sprogøe, Kennett; Staerk, Dan; Jäger, Anna K; Adsersen, Anne; Hansen, Steen Honoré; Witt, Matthias; Landbo, Anne-Katrine R; Meyer, Anne S; Jaroszewski, Jerzy W

2007-09-07

88

SPE-GC/FTD determination of N-methyl-2-pyrrolidone and its metabolites in urine.  

PubMed

An analytical method using a combination of solid-phase extraction (SPE) and gas chromatography with a flame thermionic detector (GC/FTD) was developed for determination of N-methyl-2-pyrrolidone (NMP), N-methylsuccinimide (MSI), and 2-hydroxy-N-methylsuccinimide (2-HMSI) in human urine. The SPE cartridge of poly(divinylbenzene/hydroxymethacrylate) used was directly loaded with urine sample, followed by elution with methyl isobutyl ketone (MIBK) and subsequent centrifugation, and the supernatant was injected into the capillary GC using a DB1701. This method allowed efficient separation of NMP, MSI, and 2-HMSI, which were nearly free of interference by other GC peaks arising from urine. Recoveries of NMP, MSI, and 2-HMSI from the SPE cartridge were about 98, 101, and 67%, respectively, with limits of detection of 0.04, 0.02, and 0.06 mg/L, respectively, which met the regulatory requirements. The present method was used for assay in biological monitoring of workers exposed to NMP in their occupational environment. PMID:17485256

Kubota, Ryuichi; Endo, Yoko; Takeuchi, Akito; Inoue, Yoshinori; Ogata, Hiroko; Ogawa, Masanori; Nakagawa, Tomoo; Onda, Nobuhiko; Endo, Ginji

2007-04-25

89

LC-SPE-NMR-MS: a total analysis system for bioanalysis.  

PubMed

Liquid chromatography (LC)-solid-phase extraction (SPE)-nuclear magnetic resonance (NMR)-mass spectrometry (MS) coupling is a key technology for fast and thorough structure elucidation of valuable mass-limited samples. Laborious serial isolation and purification procedures of metabolites, byproducts or impurities from complex biomatrices, natural product extracts or other mixtures of several components can be circumvented by the use of this integrated modular system. This combination of high-end analytical technology significantly accelerates the structure-elucidation process for valuable samples present in minute quantities in mixtures. The information depth is significantly increased by the concurrent availability of NMR and MS data of one chromatographic peak. Thus, this flexible technique is well on its way to becoming the gold standard in analytical chemistry of mixtures. LC-SPE-NMR-MS overcomes the limitations of directly coupled LC-NMR. Full flexibility regarding chromatographic conditions and NMR acquisition is gained by this modular technique. LC-SPE-NMR-MS allows for a rapid structure-elucidation process that would not be possible on the basis of MS or NMR data alone. PMID:21083152

Schlotterbeck, Götz; Ceccarelli, Simona M

2009-06-01

90

SolidPhase Extraction (SPE) and HPLC Analysis of Toxic Compounds and Comparison of SPE and Liquid-Liquid Extraction. I. Analysis of 4, 4?-Methyl-Enedianiline in Serum. II. Analysis of the Components of Dental Materials  

Microsoft Academic Search

In this paper, we discuss two subjects concerned with solid phase extraction (SPE) and HPLC analysis of toxic compounds eluted to serum from materials used for medical devices. SPE and liquid-liquid extraction for serum toxic compounds were compared. Firstly, an analysis of a toxic and carcinogenic compound, 4,4?-methylenedianiline (MDA), from polyurethane sterilized by gamma-ray irradiation was studied. Serum MDA was

H. Shintani

1992-01-01

91

Development of colorimetric solid phase extraction (C-SPE) for in-flight monitoring of spacecraft water supplies  

Microsoft Academic Search

Colorimetric solid phase extraction (C-SPE) is a sorption-spectrophotometric technique that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water samples. In C-SPE, a syringe is used to meter a known volume of sample through a membrane impregnated with a selective colorimetric reagent along with any additives required to optimize the complexation of the

Daniel Bryan Gazda

2004-01-01

92

Fertilization in C. elegans requires an intact C-terminal RING finger in sperm protein SPE42  

Microsoft Academic Search

Background  The C. elegans sperm protein SPE-42, a membrane protein of unknown structure and molecular function, is required for fertilization. Sperm\\u000a from worms with spe-42 mutations appear normal but are unable to fertilize eggs. Sequence analysis revealed the presence of 8 conserved cysteine\\u000a residues in the C-terminal cytoplasmic domain of this protein suggesting these residues form a zinc-coordinating RING finger\\u000a structure.

Luke D Wilson; Jacqueline M Sackett; Bryce D Mieczkowski; Abigail L Richie; Kara Thoemke; Jon N Rumbley; Tim L Kroft

2011-01-01

93

The design of an on-line semi-preparative LC-SPE-NMR system for trace analysis.  

PubMed

This paper reports the design of an on-line semi-preparative LC-SPE-NMR system and its use in the structural analysis of mixture components at the 0.02-1% level. The combination provides at least a five fold mass sensitivity increase over that obtained from typical analytical LC-SPE systems and a >30-fold total NMR sensitivity enhancement over analysis by LC-NMR. This is accomplished by using a novel on-line device to store, dilute (1-100-fold) and deliver (at an optimized flow-rate) the isolated component of interest to an SPE trap unit. The SPE unit consists of two cartridges connected in parallel to increase the overall SPE capacity and also to decrease the flow-rate through each trap for enhanced trapping efficiency. As the coupling of semi-preparative LC with NMR (through SPE) is well matched in terms of optimal mass loading for both techniques, only one LC-SPE cycle is required to enrich a 50 microg ml(-1) component (1% in a 5 mg ml(-1) mixture) for the acquisition of heteronuclear (1)H-(13)C NMR data using a conventional NMR flow probe. Furthermore, analytes at the 0.02% level (approximately 1 microg ml(-1)) can be studied using 2D (1)H NMR techniques if peak cuts from replicate sample injections (> or =3) are accumulated into the storage/dilution unit and the resulting solution processed by just one SPE trap and elute cycle. PMID:16049948

Xu, Feng; Alexander, Anthony J

2005-09-01

94

Salvianolic Acid B Induces Apoptosis in Human Glioma U87 Cells Through p38-Mediated ROS Generation.  

PubMed

Salvianolic acid B (SalB), the main water-soluble bioactive compounds isolated from the traditional Chinese medical herb Danshen, has been shown to exert anti-cancer effect in several cancer cell lines. The aim of our study was to investigate the potential anti-cancer effect of SalB in human glioma U87 cells. We found that treatment with SalB significantly decreased cell viability of U87 cells in a dose- and time-dependent manner. SalB also enhanced the intracellular ROS generation and induced apoptotic cell death in U87 cells. Western blot analysis suggested that SalB increased the phosphorylation of p38 MAPK and p53 in a dose-dependent manner. Moreover, blocking p38 activation by specific inhibitor SB203580 or p38 specific siRNA partly reversed the anti-proliferative and pro-apoptotic effects, and ROS production induced by SalB treatment. The anti-tumor activity of SalB in vivo was also demonstrated in U87 xenograft glioma model. All of these findings extended the anti-cancer effect of SalB in human glioma cell lines, and suggested that these inhibitory effects of SalB on U87 glioma cell growth might be associated with p38 activation mediated ROS generation. Thus, SalB might be concerned as an effective and safe natural anticancer agent for glioma prevention and treatment. PMID:23842993

Wang, Zi-Shu; Luo, Peng; Dai, Shu-Hui; Liu, Zao-Bin; Zheng, Xin-Rui; Chen, Tao

2013-07-11

95

spe-10 Encodes a DHHC-CRD Zinc-Finger Membrane Protein Required for Endoplasmic Reticulum/Golgi Membrane Morphogenesis During Caenorhabditis elegans Spermatogenesis  

PubMed Central

C. elegans spermatogenesis employs lysosome-related fibrous body–membranous organelles (FB–MOs) for transport of many cellular components. Previous work showed that spe-10 mutants contain FB–MOs that prematurely disassemble, resulting in defective transport of FB components into developing spermatids. Consequently, spe-10 spermatids are smaller than wild type and contain defective FB–MO derivatives. In this article, we show that spe-10 encodes a four-pass integral membrane protein that has a DHHC–CRD zinc-finger motif. The DHHC–CRD motif is found in a large, diverse family of proteins that have been implicated in palmitoyl transfer during protein lipidation. Seven spe-10 mutants were analyzed, including missense, nonsense, and deletion mutants. An antiserum to SPE-10 showed significant colocalization with a known marker for the FB–MOs during wild-type spermatogenesis. In contrast, the spe-10(ok1149) deletion mutant lacked detectable SPE-10 staining; this mutant lacks a spe-10 promoter and most coding sequence. The spe-10(eb64) missense mutation, which changes a conserved residue within the DHHC–CRD domain in all homologues, behaves as a null mutant. These results suggest that wild-type SPE-10 is required for the MO to properly deliver the FB to the C. elegans spermatid and the DHHC–CRD domain is essential for this function.

Gleason, Elizabeth J.; Lindsey, Wesley C.; Kroft, Tim L.; Singson, Andrew W.; L'Hernault, Steven W.

2006-01-01

96

Bag-SPE--a convenient extraction method for screening of pharmaceutical residues in influent and effluent water from sewage treatment plants.  

PubMed

Bag-SPE is a solid-phase extraction (SPE) technique here applied to sample pharmaceutical residues in wastewater. The device, consisting of 20 mg polystyrene-divinylbenzene (PS-DVB) enclosed in a woven polyester fabric was immersed into a 20-mL sample. Extraction of the analytes was performed under gentle rotation (25 rpm) until distribution equilibrium was achieved (4 h). The extraction efficiency for thirteen pharmaceuticals was evaluated for the bag-SPE sampler compared to a conventional SPE cartridge (Oasis HLB). All analyses were determined on an ultra-performance liquid chromatography (UPLC) coupled to a quadrupole time-of-flight (QToF) mass spectrometer. The detection limit of the bag-SPE technique for the analytes in wastewater ranged from 15-100 ng/L with recoveries between 20.7% and 58.2% and ion suppressions between 2.2% and 53.2%. Although the extraction efficiencies were lower with the bag-SPE sampler compared to the SPE technique, the two methods showed similar detection limits due to the lower ion suppression experienced with the bag-SPE. The results demonstrate that bag-SPE is an attractive alternative to the more, in terms of manual handling, demanding SPE technique. PMID:19756534

Magnér, J A; Alsberg, T E; Broman, D

2009-09-09

97

Potassium Deprivation-Induced Apoptosis of Cerebellar Granule Neurons: A Sequential Requirement for New mRNA and Protein Synthesis, ICE-Like Protease Activity, and Reactive Oxygen Species  

Microsoft Academic Search

Potassium (K1) deprivation-induced apoptosis of cerebellar granule neurons requires new mRNA and protein synthesis. Using a fluorogenic substrate for interleukin-1b converting en- zyme (ICE), we show that K1 deprivation of cerebellar granule neurons induces cycloheximide-sensitive ICE-like protease ac- tivity. A peptide inhibitor of ICE-like protease activity, Ac- YVAD-chloromethylketone (Ac-YVAD-CMK), prevents K1 deprivation-induced apoptosis. Further, reactive oxygen spe- cies (ROS) are

Jorg B. Schulz; Michael Weller; Thomas Klockgether

98

Retention behaviour of some high-intensity sweeteners on different SPE sorbents.  

PubMed

The objective of this paper is to provide information about application of solid-phase extraction (SPE) for isolation of nine high-intensity sweeteners (acesulfame-K, alitame, aspartame, cyclamate, dulcin, neotame, saccharin, sucralose and neohesperidin dihydrochalcone) from aqueous solutions. The influence of several types of LC-MS compatible buffers (different pH values and compositions) on their recovery has been studied and discussed. A number of commercially available SPE cartridges, such as Chromabond C18ec, Strata-X RP, Bakerbond Octadecyl, Bakerbond SDB-1, Bakerbond SPE Phenyl, Oasis HLB, LiChrolut RP-18, Supelclean LC-18, Discovery DSC-18 and Zorbax C18 were tested in order to evaluate their applicability for the isolation of analytes. Very high recoveries (better than 92%) of all studied compounds were obtained using formic acid-N,N-diisopropylethylamine buffer adjusted to pH 4.5 and C(18)-bonded silica sorbents. Behaviour of polymeric sorbents strongly depends on their structure. Strata-X RP behaves much like a C(18)-bonded silica sorbent. Recoveries obtained using Oasis HLB were comparable with those observed for silica-based sorbents. The only compound less efficiently (83%) retained by this sorbent was cyclamate. Bakerbond SDB-1 shows unusual selectivity towards aspartame and alitame. Recoveries of these two sweeteners were very low (26 and 42%, respectively). It was also found that aspartame and alitame can be selectively separated from the mixture of sweeteners using formic acid-triethylamine buffer at pH 3.5. PMID:20875571

Zygler, Agata; Wasik, Andrzej; Namie?nik, Jacek

2010-08-06

99

Estimates of HZE particle contributions to SPE radiation exposures on interplanetary missions.  

PubMed

Estimates of radiation doses resulting from possible HZE (high energy heavy ion) components of solar particle events (SPEs) are presented for crews of manned interplanetary missions. The calculations assume a model spectrum obtained by folding measured solar flare HZE particle abundances with the measured energy spectra of SPE alpha particles. These hypothetical spectra are then transported through aluminum spacecraft shielding. The results, presented as estimates of absorbed dose and dose equivalent, indicate that HZE components by themselves are not a major concern for crew protection but should be included in any overall risk assessment. The predictions are found to be sensitive to the assumed spectral hardness parameters. PMID:11538032

Townsend, L W; Cucinotta, F A; Wilson, J W; Bagga, R

1994-01-01

100

LC-MS-MS determination of brostallicin in human plasma following automated on-line SPE.  

PubMed

LC-MS-MS method using automated on-line solid-phase extraction (SPE) has been developed and validated for the quantitation of brostallicin (I), a new distamycin derivative, in human plasma. I is a DNA minor groove binder currently under phase I-II clinical evaluation as an anticancer drug. Plasma (0.4 ml) was spiked with 0.2 ml stable label IS solution and placed in a 96-well plate maintained at +4 degrees C. Aliquots of 0.1 ml of prepared samples were loaded into the on-line SPE HySphere Resin SH cartridges (10 mm x 2 mm ID) and the analytes back eluted with the mobile phase into LC-MS-MS system. A Platinum Cyano column (100 mm x 4.6 mm, 3.6 microm) was used to perform the chromatographic analysis. The mobile phase was acetonitrile-ammonium formate buffer (pH 3.5; 20 mM) (70:30, v/v) at a flow rate of 1.0 ml/min. LC flow was split so that 300 microl/min was directed toward the mass spectrometer interface. Retention time of I was 2.6 min and the total cycle time was 8 min. MS detection used an Applied Biosystems/MDS SCIEX API 365 with a TurboIonSpray interface and MRM (m/Z: 725/257 for I and m/Z: 729/257 for IS) operated in positive ion mode. The method was validated over the calibration range 0.124-497 ng/ml. A negligible carry-over effect from the system was observed. In spite of the known instability of I in human plasma (about 20% decrease over 12 h), the ratio analyte/IS peak area showed good stability over the analysis time required for 96 samples. The automated on-line SPE method can be considered as a valid alternative to the off-line manual SPE procedure previously developed. PMID:12899950

Calderoli, Sara; Colombo, Emiliana; Frigerio, Enrico; James, Christopher A; Sibum, Martin

2003-08-01

101

Development of colorimetric solid phase extraction (C-SPE) for in-flight monitoring of spacecraft water supplies  

NASA Astrophysics Data System (ADS)

Colorimetric solid phase extraction (C-SPE) is a sorption-spectrophotometric technique that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water samples. In C-SPE, a syringe is used to meter a known volume of sample through a membrane impregnated with a selective colorimetric reagent along with any additives required to optimize the complexation of the reagent and analyte. As the sample is passed through the membrane, analytes are extracted and complexed, leading to a detectable change in the optical characteristics of the membrane. The analyte-reagent complex is then quantified directly on the membrane, using a hand-held diffuse reflectance spectrophotometer. This dissertation focuses on the development, ground testing, and microgravity flight demonstration of C-SPE methods to meet the near- and long-term water quality monitoring needs of NASA. To this end, the ability of C-SPE to function in a microgravity environment was tested through performance evaluations of methods for the determination of the biocidal agents silver(I) and iodine on the KC-135 microgravity simulator. The biocidal iodine platform was investigated further to determine which iodine species is responsible for the C-SPE signal. Through systematic comparisons of C-SPE results and UV-Visible absorbance studies it was determined that biocidally active I2 is the iodine species complexed by poly(vinylpyrrolidone). The application of C-SPE to additional target water quality parameters is demonstrated through the determination of nickel(II), a metal leachate found in archived water samples from the International Space Station, using dimethylglyoxime. This method introduced a new variation of C-SPE, the quantification of trace analytes based on the collection of an insoluble, colored precipitate. The nickel(II) method was then combined with the method for biocidal silver(I) and a new method to measure sample pH to create a multiplexed C-SPE platform. This invention is presented as an approach to increase the collection of on-orbit water quality data collected without requiring additional crew time. The dissertation is concluded with a summation of the current work and a look at future directions.

Gazda, Daniel Bryan

102

Cotton HILIC SPE microtips for microscale purification and enrichment of glycans and glycopeptides.  

PubMed

Solid-phase extraction microtips are important devices in modern bioanalytics, as they allow miniaturized sample preparation for mass spectrometric analysis. Here we introduce the use of cotton wool for the preparation of filter-free HILIC SPE microtips. To this end, pieces of cotton wool pads (approximately 500 ?g) were packed into 10 ?L pipet tips. The performance of the tips was evaluated for microscale purification of tryptic IgG Fc N-glycopeptides. Cotton wool HILIC SPE microtips allowed the removal of salts, most nonglycosylated peptides, and detergents such as SDS from glycoconjugate samples. MALDI-TOF-MS glycopeptide profiles were very repeatable with different tips as well as reused tips, and very similar profiles were obtained with different brands of cotton wool pads. In addition, we used cotton HILIC microtips to purify N-glycans after N-glycosidase F treatment of IgG and transferrin followed by MALDI-TOF-MS detection. In conclusion, we establish cotton wool microtips for glycan and glycopeptide purification with subsequent mass spectrometric detection. PMID:21366235

Selman, Maurice H J; Hemayatkar, Mahdi; Deelder, André M; Wuhrer, Manfred

2011-03-02

103

SpeB of Streptococcus pyogenes Differentially Modulates Antibacterial and Receptor Activating Properties of Human Chemokines  

PubMed Central

Background CXC chemokines are induced by inflammatory stimuli in epithelial cells and some, like MIG/CXCL9, IP–10/CXCL10 and I–TAC/CXCL11, are antibacterial for Streptococcus pyogenes. Methodology/Principal Findings SpeB from S. pyogenes degrades a wide range of chemokines (i.e. IP10/CXCL10, I-TAC/CXCL11, PF4/CXCL4, GRO?/CXCL1, GRO?/CXCL2, GRO?/CXCL3, ENA78/CXCL5, GCP-2/CXCL6, NAP-2/CXCL7, SDF-1/CXCL12, BCA-1/CXCL13, BRAK/CXCL14, SRPSOX/CXCL16, MIP-3?/CCL20, Lymphotactin/XCL1, and Fractalkine/CX3CL1), has no activity on IL-8/CXCL8 and RANTES/CCL5, partly degrades SRPSOX/CXCL16 and MIP-3?/CCL20, and releases a 6 kDa CXCL9 fragment. CXCL10 and CXCL11 loose receptor activating and antibacterial activities, while the CXCL9 fragment does not activate the receptor CXCR3 but retains its antibacterial activity. Conclusions/Significance SpeB destroys most of the signaling and antibacterial properties of chemokines expressed by an inflamed epithelium. The exception is CXCL9 that preserves its antibacterial activity after hydrolysis, emphasizing its role as a major antimicrobial on inflamed epithelium.

Egesten, Arne; Olin, Anders I.; Linge, Helena M.; Yadav, Manisha; Morgelin, Matthias; Karlsson, Anna; Collin, Mattias

2009-01-01

104

Analgesic efficacy of sodium salicylate in an amphotericin B-induced bovine synovitis-arthritis model  

Microsoft Academic Search

This study examined the efficacy of sodium salicylate for providing analgesia in an amphotericin B-induced bovine synovitis-arthritis model using 10 male Holstein calves, 4 to 6 mo old and weighing approximately 250 kg. The study used a repeated measures partial crossover design with 2 phases, consisting of 3 treat- ment periods within each phase. Calves were blocked by body weight

JAMIE LEE KOTSCHWAR; J. F. Coetzee; D. E. Anderson; R. Gehring; B. KuKanich; M. D. Apley

2009-01-01

105

Ram ion scattering caused by Space Shuttle v x B induced differential charging  

Microsoft Academic Search

Observations of secondary, high-inclination ions streams have been reported in the literature. The authors of these previous papers attributed the source of the secondary ions to a disturbed region in the plasma about 10 m from the Space Shuttle Orbiter. A new theory has been developed which shows how v x B induced differential charging on the plasma diagnostics package

I. Katz; V. A. Davis

1987-01-01

106

Yersinia enterocolitica YopT and Clostridium difficile Toxin B Induce Expression of GILZ in Epithelial Cells  

PubMed Central

Glucocorticoid induced-leucine zipper (GILZ) has been shown to be induced in cells by different stimuli such as glucocorticoids, IL-10 or deprivation of IL-2. GILZ has anti-inflammatory properties and may be involved in signalling modulating apoptosis. Herein we demonstrate that wildtype Yersinia enterocolitica which carry the pYV plasmid upregulated GILZ mRNA levels and protein expression in epithelial cells. Infection of HeLa cells with different Yersinia mutant strains revealed that the protease activity of YopT, which cleaves the membrane-bound form of Rho GTPases was sufficient to induce GILZ expression. Similarly, Clostridium difficile toxin B, another bacterial inhibitor of Rho GTPases induced GILZ expression. YopT and toxin B both increased transcriptional activity of the GILZ promoter in HeLa cells. GILZ expression could not be linked to the inactivation of an individual Rho GTPase by these toxins. However, forced expression of RhoA and RhoB decreased basal GILZ promoter activity. Furthermore, MAPK activation proved necessary for profound GILZ induction by toxin B. Promoter studies and gel shift analyses defined binding of upstream stimulatory factor (USF) 1 and 2 to a canonical c-Myc binding site (E-box) in the GILZ promoter as a crucial step of its trans-activation. In addition we could show that USF-1 and USF-2 are essential for basal as well as toxin B induced GILZ expression. These findings define a novel way of GILZ promoter trans-activation mediated by bacterial toxins and differentiate it from those mediated by dexamethasone or deprivation of IL-2.

Koberle, Martin; Goppel, David; Grandl, Tanja; Gaentzsch, Peer; Manncke, Birgit; Berchtold, Susanne; Muller, Steffen; Luscher, Bernhard; Asselin-Labat, Marie-Liesse; Pallardy, Marc; Sorg, Isabel; Langer, Simon; Barth, Holger; Zumbihl, Robert; Autenrieth, Ingo B.; Bohn, Erwin

2012-01-01

107

Yersinia enterocolitica YopT and Clostridium difficile toxin B induce expression of GILZ in epithelial cells.  

PubMed

Glucocorticoid induced-leucine zipper (GILZ) has been shown to be induced in cells by different stimuli such as glucocorticoids, IL-10 or deprivation of IL-2. GILZ has anti-inflammatory properties and may be involved in signalling modulating apoptosis. Herein we demonstrate that wildtype Yersinia enterocolitica which carry the pYV plasmid upregulated GILZ mRNA levels and protein expression in epithelial cells. Infection of HeLa cells with different Yersinia mutant strains revealed that the protease activity of YopT, which cleaves the membrane-bound form of Rho GTPases was sufficient to induce GILZ expression. Similarly, Clostridium difficile toxin B, another bacterial inhibitor of Rho GTPases induced GILZ expression. YopT and toxin B both increased transcriptional activity of the GILZ promoter in HeLa cells. GILZ expression could not be linked to the inactivation of an individual Rho GTPase by these toxins. However, forced expression of RhoA and RhoB decreased basal GILZ promoter activity. Furthermore, MAPK activation proved necessary for profound GILZ induction by toxin B. Promoter studies and gel shift analyses defined binding of upstream stimulatory factor (USF) 1 and 2 to a canonical c-Myc binding site (E-box) in the GILZ promoter as a crucial step of its trans-activation. In addition we could show that USF-1 and USF-2 are essential for basal as well as toxin B induced GILZ expression. These findings define a novel way of GILZ promoter trans-activation mediated by bacterial toxins and differentiate it from those mediated by dexamethasone or deprivation of IL-2. PMID:22792400

Köberle, Martin; Göppel, David; Grandl, Tanja; Gaentzsch, Peer; Manncke, Birgit; Berchtold, Susanne; Müller, Steffen; Lüscher, Bernhard; Asselin-Labat, Marie-Liesse; Pallardy, Marc; Sorg, Isabel; Langer, Simon; Barth, Holger; Zumbihl, Robert; Autenrieth, Ingo B; Bohn, Erwin

2012-07-09

108

The first asteroid observations using the new SpeX instrument at the NASA Infrared Telescope Facility.  

NASA Astrophysics Data System (ADS)

SpeX is a medium-resolution 0.8-2.5 micron spectrograph built at the Institute for Astronomy (IfA) for the NASA Infrared Telescope Facility (IRTF) on Mauna Kea. In June of this year SpeX became available to observers on a shared-risk basis. On June 27-30 the first asteroid observations with SpeX were performed. A summary of the preliminary results of those observations will be reported. During the course of the observing run SpeX performance was excellent with no instrument downtime. The user interface is similar to that of the NSFCAM instrument at the IRTF. Observers familiar with the NSFCAM interface will find that of SpeX more advanced, but still fairly straightforward to learn. This new instrument has several observing modes that vary in resolution. The 0.8-2.5 micron single-prism (or low resolution) mode is useful for solid, rocky bodies whose spectra may exhibit relatively broad absorption features in this region. A variety of asteroids were observed over the course of the four nights with seeing conditions on two nights that approached the theoretical limit for the IRTF. These targets were primarily members of dynamical asteroid families, which were in keeping with the nature of the project that was awarded time. Taxonomic types observed included F, M, P, S, and V, as well as several unclassified asteroids. In addition, a few targets of opportunity were observed, some of which are potential family remnants or escapees. Perhaps the most prominent among these favorable asteroids was 433 Eros. Zappala et al. (1997, Icarus 129, 1-20) suggested that Eros may have originated as part of the Maria asteroid family. Though more recently Eros has been the subject of scrutiny by the NEAR-Shoemaker spacecraft. Preliminary spectra of the asteroids from these new, ground-based observations using SpeX will be presented.

Kelley, M. S.; Hardersen, P. S.; Gaffey, M. J.

2000-10-01

109

Fractionation and determination of aluminum and iron in soil water samples using SPE cartridges and ICP-AES.  

PubMed

The use of commercially available solid phase extraction (SPE) cartridges for the fractionation of Al and Fe in soil water is described. The quantitative determination was done by inductively coupled plasma atomic emission spectrometry (ICP-AES). Different types of SPE cartridges, based on cation exchange, anion exchange, and chelation were studied. To avoid pH changes, the SPE cartridge should be conditioned with a buffer that has a pH close to that of the sample. Both strong cation exchange (SCX) and chelation were found to work well, whereas low recovery was observed for Al when anion exchange was used. For Fe, the sum of the anionic and cationic fractions that passed through the cartridges was nearly 100%. The results obtained for Al for 23 soil water samples using a SPE/SCX cartridge and ICP-AES were compared with equilibrium calculations using the program ALCHEMI and also with a fractionation method that was based on separation on a manually prepared SCX column and detection by molecular spectrophotometry, after complexation with pyrocatechol violet (SCX-PCV method). The SPE/SCX-ICP-AES results for the labile Al fraction (Al bound to the SCX cartridge) showed an acceptable correlation with the results obtained by the equilibrium calculations, except for the samples with the highest DOC concentrations, whereas the values obtained for labile Al by the more traditional SCX-PCV method were much lower. We recommend that the SPE/SCX-ICP-AES procedure described in this work be selected for the fractionation of Al and Fe species in soil and freshwater samples. PMID:12521170

Tangen, Gaute; Wickstrøm, Torild; Lierhagen, Syverin; Vogt, Rolf; Lund, Walter

2002-12-15

110

Signal Transducer and Activator of Transcription-5 Mediates Neuronal Apoptosis Induced by Inhibition of Rac GTPase Activity*  

PubMed Central

In several neuronal cell types, the small GTPase Rac is essential for survival. We have shown previously that the Rho family GTPase inhibitor Clostridium difficile toxin B (ToxB) induces apoptosis in primary rat cerebellar granule neurons (CGNs) principally via inhibition of Rac GTPase function. In the present study, incubation with ToxB activated a proapoptotic Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, and a pan-JAK inhibitor protected CGNs from Rac inhibition. STAT1 expression was induced by ToxB; however, CGNs from STAT1 knock-out mice succumbed to ToxB-induced apoptosis as readily as wild-type CGNs. STAT3 displayed enhanced tyrosine phosphorylation following treatment with ToxB, and a reputed inhibitor of STAT3, cucurbitacin (JSI-124), reduced CGN apoptosis. Unexpectedly, JSI-124 failed to block STAT3 phosphorylation, and CGNs were not protected from ToxB by other known STAT3 inhibitors. In contrast, STAT5A tyrosine phosphorylation induced by ToxB was suppressed by JSI-124. In addition, roscovitine similarly inhibited STAT5A phosphorylation and protected CGNs from ToxB-induced apoptosis. Consistent with these results, adenoviral infection with a dominant negative STAT5 mutant, but not wild-type STAT5, significantly decreased ToxB-induced apoptosis of CGNs. Finally, chromatin immunoprecipitation with a STAT5 antibody revealed increased STAT5 binding to the promoter region of prosurvival Bcl-xL. STAT5 was recruited to the Bcl-xL promoter region in a ToxB-dependent manner, and this DNA binding preceded Bcl-xL down-regulation, suggesting transcriptional repression. These data indicate that a novel JAK/STAT5 proapoptotic pathway significantly contributes to neuronal apoptosis induced by the inhibition of Rac GTPase.

Stankiewicz, Trisha R.; Loucks, F. Alexandra; Schroeder, Emily K.; Nevalainen, Marja T.; Tyler, Kenneth L.; Aktories, Klaus; Bouchard, Ron J.; Linseman, Daniel A.

2012-01-01

111

Uranus' cloud particle properties and latitudinal methane variation from IRTF SpeX observations  

NASA Astrophysics Data System (ADS)

The Uranian atmosphere was observed in August 2009 from 0.8 to 1.8 ?m using the near-infrared spectrometer, SpeX, at NASA's Infrared Telescope Facility. The observations had a spectral resolution of R = 1200 and an average seeing of between 0.5? in the H-Band (1.4–1.8 ?m) and 0.6? in the I-Band (0.8–0.9 ?m). The reduced data were analyzed with a multiple-scattering retrieval code. We were able to reproduce observations when using a vertically-compact cloud in the upper troposphere and a vertically-extended, optically-thin haze above the 1-bar level. The existence of these two clouds is consistent with previous studies.

Tice, Dane S.; Irwin, Patrick G. J.; Fletcher, Leigh N.; Teanby, Nick A.; Hurley, Jane; Orton, Glenn S.; Davis, Gary R.

2013-04-01

112

Asteroid 21 Lutetia at 3-4m: Observations with IRTF SpeX  

NASA Astrophysics Data System (ADS)

We present observations of asteroid 21 Lutetia collected 2003-2008 using the SpeX instrument on the NASA Infrared Telescope Facility (IRTF) covering 2-4 ?m. We also reevaluate NSFCam observations obtained in 1996 [1]. Taken together, these show deeper 3-?m band depths (˜3-5%) in the southern hemisphere of Lutetia, and shallower band depths (? 2%) in the north. Such variation is consistent with observations at shorter wavelength by previous workers [2,3], who observed hemisphericlevel variations from C-like spectra to X-like spectra. It is also consistent with Rosetta's reported nondetection of an OH band in Lutetia's northern hemisphere [4]. While the shallowness of absorption bands on Lutetia hinders identification of its surface composition, goethite appears plausible as a constituent in its southern hemisphere [5].

Rivkin, A. S.; Clark, B. E.; Ockert-Bell, M. E.; Shepard, M. K.; Volquardsen, E. L.; Howell, E. S.; Bus, S. J.

2011-10-01

113

Optimization of an SPE and GC/MS Method for Analyzing Endocrine Disrupting Compounds in Water  

NASA Astrophysics Data System (ADS)

Endocrine disrupting compounds (EDCs) are compounds that interrupt hormonal functions in the body. The literature reports the presence of EDCs in all environmental matrices (air, water and soil) at concentrations of at least 1 nanogram/liter (ng/l), which may be high enough to induce adverse health effects. Therefore, reliable analytical methods for detecting trace amounts of EDCs in water is very important for investigating and controlling their concentrations in the environment. This study investigated a method for analyzing four known or suspected EDCs (chlorpyrifos, musk HHCB, diethyl phthalate, and butylated hydroxyanisole) in water samples. The analytical method was based on the USGS wastewater method developed by Zaugg et al. (2001), but modified, using solid phase extraction (SPE) followed by gas chromatography and mass spectrometry (GC/MS) analysis. The EDCs were extracted using 60mg Water Oasis hydrophilic-lipophillic balance (HLB) extraction cartridges. The SPE efficiency was investigated by using different initial extraction volumes and different EDC concentrations. The lowest concentration was 1ng/l and the lowest extraction volume was 100mL. Results of the study indicate that the initial oven temperature conditions and rate of temperature increases affects the peak signal to noise ratio and the sample run-time in the GC/MS. An increase in gas flow rate did not show any significant changes and hence was maintained at 1ml/min. Preliminary data suggests that the percent recovery of the compounds obtained using this method either met or exceeded those presented by Zaugg et al. (2001) as the USGS wastewater method.

Thomas, S. M.; Bodour, A.; Murray, K. E.

2006-12-01

114

A Naturally Occurring Mutation in ropB Suppresses SpeB Expression and Reduces M1T1 Group A Streptococcal Systemic Virulence  

PubMed Central

Epidemiological studies of group A streptococcus (GAS) have noted an inverse relationship between SpeB expression and invasive disease. However, the role of SpeB in the course of infection is still unclear. In this study we utilize a SpeB-negative M1T1 clinical isolate, 5628, with a naturally occurring mutation in the gene encoding the regulator RopB, to elucidate the role of RopB and SpeB in systemic virulence. Allelic exchange mutagenesis was used to replace the mutated ropB allele in 5628 with the intact allele from the well characterized isolate 5448. The inverse allelic exchange was also performed to replace the intact ropB in 5448 with the mutated allele from 5628. An intact ropB was found to be essential for SpeB expression. While the ropB mutation was shown to have no effect on hemolysis of RBC's, extracellular DNase activity or survival in the presence of neutrophils, strains with the mutated ropB allele were less virulent in murine systemic models of infection. An isogenic SpeB knockout strain containing an intact RopB showed similarly reduced virulence. Microarray analysis found genes of the SpeB operon to be the primary target of RopB regulation. These data show that an intact RopB and efficient SpeB production are necessary for systemic infection with GAS.

Hollands, Andrew; Aziz, Ramy K.; Kansal, Rita; Kotb, Malak; Nizet, Victor; Walker, Mark J.

2008-01-01

115

Cysteine proteinase SpeB from Streptococcus pyogenes - a potent modifier of immunologically important host and bacterial proteins.  

PubMed

Group A streptococcus (Streptococcus pyogenes) is an exclusively human pathogen that causes a wide spectrum of diseases ranging from pharyngitis, to impetigo, to toxic shock, to necrotizing fasciitis. The diversity of these disease states necessitates that S. pyogenes possess the ability to modulate both the innate and adaptive immune responses. SpeB, a cysteine proteinase, is the predominant secreted protein from S. pyogenes. Because of its relatively indiscriminant specificity, this enzyme has been shown to degrade the extracellular matrix, cytokines, chemokines, complement components, immunoglobulins, and serum protease inhibitors, to name but a few of the known substrates. Additionally, SpeB regulates other streptococcal proteins by degrading them or releasing them from the bacterial surface. Despite the wealth of literature on putative SpeB functions, there remains much controversy about this enzyme because many of reported activities would produce contradictory physiological results. Here we review all known host and bacterial protein substrates for SpeB, their cleavage sites, and discuss the role of this enzyme in streptococcal pathogenesis based on the current literature. PMID:22050223

Nelson, Daniel C; Garbe, Julia; Collin, Mattias

2011-12-01

116

Nucleotide sequence and analysis of the speA gene encoding biosynthetic arginine decarboxylase in Escherichia coli.  

PubMed Central

The DNA sequence of a 3.23-kilobase fragment of the Escherichia coli chromosome encoding biosynthetic arginine decarboxylase (ADC) was determined. This sequence contained the speA open reading frame (ORF) as well as partial speB and metK ORFs. The ADC ORF is 1,974 nucleotides long; the deduced polypeptide contains 658 amino acids with a molecular size of 73,980 daltons. The molecular weight and predicted ADC amino acid composition are nearly identical to the amino acid analysis of purified ADC performed by Wu and Morris (J. Biol. Chem. 248:1687-1695, 1973). A translational speA-lacZ fusion, pRM65, including 1,389 base pairs (463 amino acids) of the 5' end of speA was constructed. Western blots (immunoblots) with beta-galactosidase antisera revealed two ADC::beta-galactosidase fusion proteins in E. coli bearing pRM65: 160,000 and 156,000 daltons representing precursor and mature hybrid proteins, respectively. The predicted amino acid sequence of ADC contains a region of six amino acid residues found in two bacterial diaminopimelic acid decarboxylases and three eucaryotic ornithine decarboxylases. This conserved sequence is located approximately eight amino acids from the putative pyridoxal phosphate-binding site of ADC and is predicted to be involved in substrate binding. Images

Moore, R C; Boyle, S M

1990-01-01

117

Observations of 103P/Hartley 2 During the EPOXI Flyby Using SpeX at the NASA IRTF  

NASA Astrophysics Data System (ADS)

This paper reports results from a 2-4 ?m spectral study of 103P/Hartley 2 using SpeX at the NASA IRTF. Such moderate-resolution spectra provide fundamental information on gases in cometary comae that complements high-resolution studies.

Vervack, R. J.; Dello Russo, N.; Weaver, H. A.; Lisse, C. M.; Kawakita, H.; Kobayashi, H.; DiSanti, M. A.

2012-05-01

118

Protective effect of granulocyte-colony stimulating factor against amphotericin B-induced myelosuppression in vitro.  

PubMed

Amphotericin B causes suppression of bone marrow (BM) progenitor cells in vitro. Granulocyte colony stimulating factor (G-CSF) enhances the proliferation of myeloid cells. The present study defines the role of G-CSF in preventing amphotericin B-induced myelosuppression. G-CSF increased the proliferative potential of BM and protected against amphotericin B-induced myelosuppression if it was added to the medium during the early phase of exposure of BM to amphotericin B. Monoclonal antibodies to tumour necrosis factor-alpha (TNF) or interferon-gamma (IFN) inhibited the myelosuppression partially; simultaneous presence of both these antibodies completely abrogated this suppression, suggesting that both TNF alpha and IFN gamma were involved in amphotericin-induced myelosuppression. TNF- or IFN-induced suppression of BM was also inhibited by G-CSF. These data suggest that G-CSF prevents the amphotericin B-induced myelosuppression by antagonizing the suppressive effects of TNF and IFN and by enhancing the proliferative activity of BM. PMID:7529537

Charak, B S; Brown, E G; Mazumder, A

1994-12-01

119

Acetylcholinesterase Involvement in Apoptosis  

PubMed Central

To date, more than 40 different types of cells from primary cultures or cell lines have shown AChE expression during apoptosis and after the induction apoptosis by different stimuli. It has been well-established that increased AChE expression or activity is detected in apoptotic cells after apoptotic stimuli in vitro and in vivo, and AChE could be therefore used as a marker of apoptosis. AChE is not an apoptosis initiator, but the cells in which AChE is overexpressed undergo apoptosis more easily than controls. Interestingly, cells with downregulated levels of AChE are not sensitive to apoptosis induction and AChE deficiency can protect against apoptosis. Some tumor cells do not express AChE, but when AChE is introduced into a tumor cell, the cells cease to proliferate and undergo apoptosis more readily. Therefore, AChE can be classified as a tumor suppressor gene. AChE plays a pivotal role in apoptosome formation, and silencing of the AChE gene prevents caspase-9 activation, with consequent decreased cell viability, nuclear condensation, and poly (adenosine diphosphate-ribose) polymerase cleavage. AChE is translocated into the nucleus, which may be an important event during apoptosis. Several questions still need to be addressed, and further studies that address the non-classical function of AChE in apoptosis are needed.

Zhang, Xue-Jun; Greenberg, David S.

2012-01-01

120

yApoptosis: yeast apoptosis database.  

PubMed

In the past few years, programmed cell death (PCD) has become a popular research area due to its fundamental aspects and its links to human diseases. Yeast has been used as a model for studying PCD, since the discovery of morphological markers of apoptotic cell death in yeast in 1997. Increasing knowledge in identification of components and molecular pathways created a need for organization of information. To meet the demands from the research community, we have developed a curated yeast apoptosis database, yApoptosis. The database structurally collects an extensively curated set of apoptosis, PCD and related genes, their genomic information, supporting literature and relevant external links. A web interface including necessary functions is provided to access and download the data. In addition, we included several networks where the apoptosis genes or proteins are involved, and present them graphically and interactively to facilitate rapid visualization. We also promote continuous inputs and curation by experts. yApoptosis is a highly specific resource for sharing information online, which supports researches and studies in the field of yeast apoptosis and cell death. Database URL: http://www.ycelldeath.com/yapoptosis/ PMID:24082050

Wanichthanarak, Kwanjeera; Cvijovic, Marija; Molt, Andrea; Petranovic, Dina

2013-09-29

121

yApoptosis: yeast apoptosis database  

PubMed Central

In the past few years, programmed cell death (PCD) has become a popular research area due to its fundamental aspects and its links to human diseases. Yeast has been used as a model for studying PCD, since the discovery of morphological markers of apoptotic cell death in yeast in 1997. Increasing knowledge in identification of components and molecular pathways created a need for organization of information. To meet the demands from the research community, we have developed a curated yeast apoptosis database, yApoptosis. The database structurally collects an extensively curated set of apoptosis, PCD and related genes, their genomic information, supporting literature and relevant external links. A web interface including necessary functions is provided to access and download the data. In addition, we included several networks where the apoptosis genes or proteins are involved, and present them graphically and interactively to facilitate rapid visualization. We also promote continuous inputs and curation by experts. yApoptosis is a highly specific resource for sharing information online, which supports researches and studies in the field of yeast apoptosis and cell death. Database URL: http://www.ycelldeath.com/yapoptosis/

Wanichthanarak, Kwanjeera; Cvijovic, Marija; Molt, Andrea; Petranovic, Dina

2013-01-01

122

Role of RopB in Growth Phase Expression of the SpeB Cysteine Protease of Streptococcus pyogenes  

PubMed Central

The Rgg family of transcription regulators is widely distributed among gram-positive bacteria; however, how the members of this family control transcription is poorly understood. In the pathogen Streptococcus pyogenes, the Rgg family member RopB is required for transcription of the gene that encodes the secreted SpeB cysteine protease. Expression of the protease follows distinct kinetics that involves control of transcription in response to the growth phase. In this study, the contribution of RopB to growth phase control was examined. The gene encoding the protease (speB) and ropB are transcribed divergently from a 940-bp intergenic region. Primer extension analyses, in conjunction with reporter fusion studies, revealed that the major region controlling the transcription of both speB and ropB is adjacent to ropB and that the promoters for the two genes likely overlap. Furthermore, it was found that RopB is a DNA-binding protein that specifically binds to sequences in this control region. The interrelationship between ropB and speB expression was further reflected in the observation that transcription of ropB itself is subject to growth phase control. However, while expression of ropB from a promoter expressed during the early logarithmic phase of growth could complement a ropB deletion mutant, ectopic expression of ropB did not uncouple the expression of speB from its growth phase signal. These data implicate other factors in growth phase control and suggest that regulation of ropB expression itself is not the central mechanism of control.

Neely, Melody N.; Lyon, William R.; Runft, Donna L.; Caparon, Michael

2003-01-01

123

Analysis of epothilone B-induced cell death in normal ovarian cells.  

PubMed

We have investigated the mode of cell death induced by a new microtubule-stabilizing agent, epothilone B (EpoB, patupilone), and a clinically used medicine, paclitaxel (PTX), in normal ovarian cells. Using fluorescence microscopy, polyacrylamide gel electrophoresis preceding Western blot analysis, as well as spectrofluorimetric and colorimetric detection, we demonstrate that, compared to EpoB, PTX induced high time-dependent morphological and biochemical changes typical of apoptosis. Induction of apoptosis followed an early increase in p53 levels. Apoptosis reached its maximum at 24-48?h. At the same time, there was a significant increase in caspase-9 and -3 activity and PARP fragmentation, which suggests that an intrinsic path was involved. Apoptosis in MM14 cells was increased more by PTX than EpoB, and also induced more necrosis responsible for inflammation (1.4-fold) than EpoB. PMID:23955989

Rogalska, Aneta; Gajek, Arkadiusz; Marczak, Agnieszka

2013-09-12

124

Determination of ethyl glucuronide in human hair by SPE and LC-MS/MS.  

PubMed

A method for the sensitive and selective determination of ethyl glucuronide (EtG) in hair has been developed using solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Washed and cut hair segments were extracted by ultrasonication (3h, 50 degrees C) and the extracts were cleaned-up with aminopropyl SPE columns. LC-MS/MS analysis was performed using a polar-endcapped phenyl-hexyl-RP-phase with negative mode electrospray ionisation (ESI) using a triple quadrupole mass spectrometer (Sciex API 365) with a turboionspray source and post-column addition of acetonitrile for enhanced sensitivity. The MS/MS transitions monitored were m/z 221 -->75 for EtG and 226 -->75 for D(5)-EtG as an internal standard. The method was selective and sensitive, with a detection limit of 51 pg/mg hair at a signal-to-noise ratio of 3:1. The mean recovery was 96%, with an intra- and inter-day precision of less than 11.7% at a concentration of 200 pg/mg. The linearity was assessed in the range of 25-2000 pg/mg hair, with a correlation coefficient of 0.997. The method was successfully applied to 97 human hair samples which were taken at autopsies from persons with known alcoholism or were obtained from alcoholics who were hospitalized for ethanol withdrawal, from social drinkers and from children having not consumed any alcohol. Although, approximately two-third of the alcoholics showed EtG concentrations in hair of higher than 51 pg/mg (up to >4000 pg/mg), in one-third the EtG concentration was below the detection limit. However, only in one of five hair samples of "social drinkers", the EtG concentration was above the detection limit (51 pg/mg). No EtG has been detected in the hair of children. These investigations demonstrate that heavy alcohol consumption may be but not necessarily has to be detectable by EtG analysis in hair. PMID:12208024

Janda, Ines; Weinmann, Wolfgang; Kuehnle, Thorsten; Lahode, Martina; Alt, Andreas

2002-08-14

125

A Naturally Occurring Rgg Variant in Serotype M3 Streptococcus pyogenes Does Not Activate speB Expression Due to Altered Specificity of DNA Binding?  

PubMed Central

The transcriptional regulator Rgg of Streptococcus pyogenes is essential for expression of the secreted cysteine protease SpeB. Although all isolates of S. pyogenes possess the speB gene, not all of them produce the protein in vitro. In a murine model of infection, the absence of SpeB production is associated with invasive disease. We speculated that naturally occurring mutations in rgg, which would also abrogate SpeB production, may be present in invasive isolates of S. pyogenes. Examination of the inferred Rgg sequences available in public databases revealed that the rgg gene in strain MGAS315 (a serotype M3 strain associated with invasive disease) encodes a proline at amino acid position 103 (Rgg103P); in contrast, all other strains encode a serine at this position (Rgg103S). A caseinolytic assay and Western blotting indicated that strain MGAS315 does not produce SpeB in vitro. Gene-swapping experiments showed that the rgg gene of MGAS315 is solely responsible for the lack of SpeB expression. In contrast to Rgg103S, Rgg103P does not bind to the speB promoter in gel shift assays, which correlates with a lack of speB expression. Despite its inability to activate speB expression, Rgg103P retains the ability to bind to DNA upstream of norA and to influence its expression. Overall, this study illustrates how variation at the rgg locus may contribute to the phenotypic diversity of S. pyogenes.

Kappeler, Kyle V.; Anbalagan, Srivishnupriya; Dmitriev, Alexander V.; McDowell, Emily J.; Neely, Melody N.; Chaussee, Michael S.

2009-01-01

126

Cellular stress and apoptosis  

Microsoft Academic Search

The morphological characteristics of apoptosis are unique and imply a series of alterations including cell shrinkage, membrane blebbing, nuclear condensation and emergence of apoptotic bodies. Three phases can be determined during the process of apoptosis: these are an induction phase corresponding to the initiation of the apoptotic signal, an effector phase involving proteolysis of important substrates and a degradation phase

M. Pallardy; M. Perrin-Wolff; A. Biola

1997-01-01

127

Calpains, mitochondria, and apoptosis  

PubMed Central

Mitochondrial activity is critical for efficient function of the cardiovascular system. In response to cardiovascular injury, mitochondrial dysfunction occurs and can lead to apoptosis and necrosis. Calpains are a 15-member family of Ca2+-activated cysteine proteases localized to the cytosol and mitochondria, and several have been shown to regulate apoptosis and necrosis. For example, in endothelial cells, Ca2+ overload causes mitochondrial calpain 1 cleavage of the Na+/Ca2+ exchanger leading to mitochondrial Ca2+ accumulation. Also, activated calpain 1 cleaves Bid, inducing cytochrome c release and apoptosis. In renal cells, calpains 1 and 2 promote apoptosis and necrosis by cleaving cytoskeletal proteins, which increases plasma membrane permeability and cleavage of caspases. Calpain 10 cleaves electron transport chain proteins, causing decreased mitochondrial respiration and excessive activation, or inhibition of calpain 10 activity induces mitochondrial dysfunction and apoptosis. In cardiomyocytes, calpain 1 activates caspase 3 and poly-ADP ribose polymerase during tumour necrosis factor-?-induced apoptosis, and calpain 1 cleaves apoptosis-inducing factor after Ca2+ overload. Many of these observations have been elucidated with calpain inhibitors, but most calpain inhibitors are not specific for calpains or a specific calpain family member, creating more questions. The following review will discuss how calpains affect mitochondrial function and apoptosis within the cardiovascular system.

Smith, Matthew A.; Schnellmann, Rick G.

2012-01-01

128

Enantiomeric resolution of ibuprofen and flurbiprofen in human plasma by SPE-chiral HPLC methods.  

PubMed

Chiral analysis of profens in human plasma is an important area of research due to different pharmaceutical activities of their enantiomers. The solid phase extraction of ibuprofen and flurbiprofen from human plasma was carried out on C18 cartridges by using phosphate buffer (50 mM, pH 6.0) followed by elution with methanol. Chiral-HPLC was performed on AmyCoat RP (150 mm x 46 mm, 3 ?m particle size) column by using different combinations of water-acetonitrile-trifluoro acetic acid at 1.5 mLmin-1 flow rate. The detection was achieved at 236 and 254 nm for ibuprofen and flurbiprofen, respectively with 27±1°C as working temperature. The chromatographic parameters i.e. retention (k), separation (?) and resolution (Rs) factors ranged from 4.54-14.42, 1.10-1.30 and 1.01-1.49, respectively. The binding differences of enantiomers of ibuprofen and flurbiprofen were 4.4 and 5.2, respectively. These values suggest that S-(+)- enantiomer of flurbiprofen is more active than ibuprofen due to low enantiomeric difference of the later drug. The developed SPE-Chiral HPLC methods were validated, which are selective, efficient and reproducible. PMID:22571370

Ali, Imran; Hussain, Iqbal; Saleem, Kishwar; Aboul-Enein, Hassan Y

2012-07-01

129

Suppressive effects of ascorbate derivatives on ultraviolet-B-induced injury in hacat human keratinocytes  

Microsoft Academic Search

Summary  The aging of skin, including sunburning, is caused by ultraviolet (UV) irradiation. Here, we examined the inhibitory effect\\u000a of ascorbic acid (AsA) and its derivatives AsA 2-phosphate (AA-2P) and AsA 2-glucoside (AA-2G) on UV-B-induced cytotoxicity\\u000a in HaCaT keratinocytes. Results show that cell viability significantly decreased when exposed to UV-B at 0.1–0.4 J\\/cm2 in a dose-dependent manner. In this study, AsA

Shin Yasuda; Mikiro Tada; Koji Yamada; Kyoya Takahata

2004-01-01

130

Apoptosis in Anthracycline Cardiomyopathy  

PubMed Central

Apoptosis is a tightly regulated physiologic process of programmed cell death that occurs in both normal and pathologic tissues. Numerous in vitro or in vivo studies have indicated that cardiomyocyte death through apoptosis and necrosis is a primary contributor to the progression of anthracycline-induced cardiomyopathy. There are now several pieces of evidence to suggest that activation of intrinsic and extrinsic apoptotic pathways contribute to anthracycline-induced apoptosis in the heart. Novel strategies were developed to address a wide variety of cardiotoxic mechanisms and apoptotic pathways by which anthracycline influences cardiac structure and function. Anthracycline-induced apoptosis provides a very valid representation of cardiotoxicity in the heart, an argument which has implications for the most appropriate animal models of damaged heart plus diverse pharmacological effects. In this review we describe various aspects of the current understanding of apoptotic cell death triggered by anthracycline. Differences in the sensitivity to anthracycline-induced apoptosis between young and adult hearts are also discussed.

Shi, Jianjian; Abdelwahid, Eltyeb; Wei, Lei

2011-01-01

131

CORRTEX Diagnostic Deployment for the SPE-III experiment, 24 July 2012: Fielding Report and Preliminary Data Analysis  

SciTech Connect

The Continuous Reflectometry for Radius vs Time Experiments (CORRTEX) diagnostic system was deployed for the third explosives test in the Source Physics Experiment (SPE) sequence to monitor and verify several conditions of the experiment including the detonation velocity of the explosive package and functioning of explosive initiators. Six distance-marked coaxial cables were installed on the SPE-III explosives canister, and key locations documented through along-cable length measurements and photography. CORRTEX uses electrical-pulse time-domain reflectometry to continuously record the two-way transit time (TWTT) of the cables. As the shock front of the detonation advances, the coaxial cable is shorted or destroyed, and the resulting TWTT also decreases. Interpretation of these changes as a function of TWTT can be converted to positional measurements using known parameters of the cables.

Sandoval, Thomas D. [Los Alamos National Laboratory; Schultz-Fellenz, Emily S. [Los Alamos National Laboratory

2012-08-29

132

Absence of SpeB Production in Virulent Large Capsular Forms of Group A Streptococcal Strain 64  

PubMed Central

Passage in human blood of group A streptococcal isolate 64p was previously shown to result in the enhanced expression of M and M-related proteins. Similarly, when this isolate was injected into mice via an air sac model for skin infection, organisms recovered from the spleens showed both increased expression of M and M-related proteins and increased skin-invasive potential. We show that these phenotypic changes were not solely the result of increased transcription of the mRNAs encoding the M and M-related gene products. Rather, the altered expression was associated with posttranslational modifications of the M and M-related proteins that occur in this strain, based on the presence or absence of another virulence protein, the streptococcal cysteine protease SpeB. The phenotypic variability also correlates with colony size variation. Large colonies selected by both regimens expressed more hyaluronic acid, which may explain differences in colony morphology. All large-colony variants were SpeB negative and expressed three distinct immunoglobulin G (IgG)-binding proteins in the M and M-related protein family. Small-colony variants were SpeB positive and bound little IgG through their M and M-related proteins because these proteins, although made, were degraded or altered in profile by the SpeB protease. We conclude that passage in either human blood or a mouse selects for a stable, phase-varied strain of group A streptococci which is altered in many virulence properties.

Raeder, Roberta; Harokopakis, Evlambia; Hollingshead, Susan; Boyle, Michael D. P.

2000-01-01

133

Simultaneous SPE-LC Determination of Three Flavonoid Glycosides of Naringin, Neohesperidin and Hesperidin in Da-Cheng-Qi Decoction  

Microsoft Academic Search

In this paper a rapid solid-phase extraction (SPE) high-performance liquid chromatographic (HPLC) method coupled with ultraviolet\\u000a detector (UV) has been developed and validated for the simultaneous analysis of three flavonoid glycosides of naringin, hesperidin\\u000a and neohesperidin in Da-Cheng-Qi (DCQ) decoction, a widely used purgative prescription of traditional Chinese medicine (TCM).\\u000a The chromatographic separation was performed on an Agilent Zorbax SB-C18

Fengguo Xu; Ying Liu; Zunjian Zhang; Rui Song; Cheng yang; Yuan Tian

2007-01-01

134

Combined SPE and HPTLC as a Screening Assay of Urinary Cotinine from Male Adolescents Exposed to Environmental Tobacco Smoke  

Microsoft Academic Search

Cotinine, as the main metabolite of nicotine, has been determined in urine using solid-phase extraction and the high-performance thin-layer chromatographic (SPE-HPTLC) method. The urine samples were collected from a group of 35 male adolescents which were moderate or significantly exposed to home environmental tobacco smoke (ETS). l-methyl-2-pyrrolidinone was used as the internal standard in the proposed screening procedure. The thin-layer

G. Bazylak; H. Brózik; W. Sabanty

135

Cassia tora Linn Cream Inhibits Ultraviolet-B-Induced Psoriasis in Rats  

PubMed Central

The aim of present study was to determine the antipsoriatic activity of newly formulated O/W creams of methanolic extract of Cassia tora L. leaves by using ultraviolet-B-induced psoriasis in rat. The plant Cassia tora L. is traditionally claimed to be useful in the treatment of a number of skin diseases. However, there are no established scientific reports for its antipsoriatic activity. Methanolic Cassia tora L. leaves extract was used to prepare various concentrations of O/W creams and tested for acute dermal toxicity study. The different O/W creams showed good physical characteristics and passed the sensitivity, irritation, grittiness and bleeding test. The results of acute dermal toxicity showed that the creams were safe up to the dose of 2000?mg/kg. In case of psoriasis model, histopathological analysis revealed that there were absence of Munro's microabscess, elongation of rete ridges, and capillary loop dilation in the section in Test 2 (0.1%) and standard group. O/W creams and methanolic extract of Cassia tora L. leaves exhibited significant reduction in percentage of relative epidermal thickness and spleen index as compared to positive control. We concluded that topical O/W creams and crude extract containing methanolic extract of Cassia tora L. leaves have potent antipsoriatic activity in ultraviolet-B-induced psoriasis in rat.

Singhal, Manmohan; Kansara, Niraj

2012-01-01

136

Application of RP-HPLC-diode array detector after SPE to the determination of pesticides in pepper samples.  

PubMed

The application of HPLC-diode array detector (DAD) after SPE for identification and quantitative analysis of pesticides in red and green pepper samples is demonstrated. An HPLC procedure on an RP column (C18) was developed for analysis of selected pesticides from different chemical groups: metamitron, metalaxyl, linuron, and prometryn. Average recoveries for C18 Polar Plus cartridges and solvents by the proposed RP-HPLC-DAD method after SPE are presented. Average recoveries from the spiked samples and the SDs were 22.5 +/- 2.2, 138.0 +/- 4.1, 78.6 +/- 2.8, and 109.2 +/- 2.3% for metamitron, metalaxyl, linuron, and prometryn, respectively, at concentrations of 7 microg/g in the plant material. The efficiency of the SPE procedure was evaluated using real food samples. The quantities of prometryn, linuron, metalaxyl, and metamitron determined were in the ranges of 0.02-2.24 microg/g (n = 24), 0.08-1.01 microg/g (n = 9), 1.61-2.28 microg/g (n=4), and 0.05-1.07 microg/g (n = 3), respectively, in plant material sampled in 2011. The method was validated for precision, repeatability, and accuracy. PMID:23175966

Tuzimski, Tomasz

137

speB gene as a specific genetic marker for early detection of rheumatic heart disease in human.  

PubMed

Streptococcus pyrogenic exotoxin B gene (speB) is chromosomally encoded pyrogenic and cardiotoxic virulence factor of S. pyogenes. Exotoxin B is produced only in a secreted form, as a 40 KD proprotein, which is subsequently processed to 28 KD in the mature form. Streptococcus pyogenes infection in human, causes initially pharyngitis due to inhalation of aerosols emitted by infected persons, develops rheumatic fever which leads to the rheumatic heart disease (damage of heart valves). The available detection methods are bacterial culture, ?-hemolysis, bacitracin sensitivity, hippurate test, phadebact test, CRP (C-reactive protein), ESR and PCR. All these methods are either expensive or non-confirmatory and have some limitations. Available PCR methods take more time and require other test to confirm the disease. Our PCR based detection of Streptococcus pyogenes in human using specific primers of speB gene completes overall analysis in 80 min which is the minimum time reported so far for the confirmation of the disease. Amplicon of 423bp of speB gene can be used as a specific genetic marker as it does not show homology with other organisms for early detection of rheumatic heart disease. Our method is specific virulence gene based which is quick, economical and more sensitive as compared with other methods. PMID:23273191

Kaushal, A; Kumar, D; Khare, S; Kumar, A

2012-12-22

138

Determination of chloramphenicol in aquatic products by graphene-based SPE coupled with HPLC-MS/MS.  

PubMed

An effective analytical protocol using graphene-based SPE coupled with HPLC-MS/MS for determination of chloramphenicol (CAP) in aquatic products has been developed. In the present work, graphene was evaluated as SPE sorbents for the analytes enrichment and clean up. The target analytes were quantified by a triple-quadrupole linear ion trap MS in multiple-reaction monitoring mode. In addition, the proposed method was validated according to Commission Decision 2002/657/EC. The calibration curve was linear over the range of 0.5-100 ng/mL. The mean values of RSD of intra- and interday ranging from 1.48 to 4.29% and from 3.25 to 7.42% were obtained, respectively. In the three fortified levels, the recoveries of CAP ranging from 92.3 to 103.4% with RSDs ? 5.58% were obtained. The proposed method has been successfully applied to the analysis of CAP in several aquatic product samples, indicating that graphene was a potential SPE sorbent for the enrichment of trace residues in food samples. PMID:23225722

Wu, Jianbing; Chen, Linyao; Mao, Peipei; Lu, Yanbin; Wang, Huizhong

2012-12-01

139

The application of LC-NMR and LC-SPE-NMR to compositional studies of natural organic matter.  

PubMed

Non-living natural organic matter (NOM) is ubiquitous in the oceans, atmosphere, sediments, and soils, and represents the most abundant organic carbon reserves on earth. However, a large proportion is considered to be "molecularly uncharacterized" because the inherent complexity of NOM is problematic when applying conventional analytical techniques. This manuscript presents initial applications of LC-NMR (1H) and LC-SPE-NMR (1H) to the studies of NOM isolated from water and soil. LC-NMR is applied to dissolved natural organic matter (DNOM) collected from freshwater environments, and both LC-NMR and LC-SPE-NMR are applied to an alkaline soil extract. The polar and complex nature of the DNOM samples limits conventional reversed phase separation, which can be partially overcome with the use of an ion pair reagent, although such an approach further complicates the NMR detection. LC-SPE-NMR of the soil alkaline extract was encouraging, and specific components in the mixture could be assigned. This work demonstrates that it is both possible to separate and concentrate specific components in NOM such that NMR detection is possible. As NMR information will be critical in unraveling the novel and/or complex structures in NOM this represents a key analytical hurdle in this area. PMID:15565221

Simpson, Andre J; Tseng, Li-Hong; Simpson, Myrna J; Spraul, Manfred; Braumann, Ulrich; Kingery, William L; Kelleher, Brian P; Hayes, Michael H B

2004-10-15

140

Characterization of a paracetamol metabolite using on-line LC-SPE-NMR-MS and a cryogenic NMR probe.  

PubMed

In this study, the hyphenation of LC-SPE-NMR-MS at 500 MHz was applied to the structural elucidation of a low concentrated paracetamol metabolite present in human urine. Single or multiple peak trapping of the mass detected metabolite on SPE cartridges was employed to increase the sensitivity and quality NMR measurement over the conventional LC-NMR method. After the elution of the metabolite from the SPE cartridge to the NMR flow probe using deuterated acetonitrile for initial NMR investigation, the fraction was revovered by flushing the sample out of the NMR probe head with nitrogen gas. On the recovered fraction, high resolution FT-ICR-MS measurements were conducted, giving exact mass information about the unknown metabolite. In addition, a cryogenic NMR micro probe head was used to enhance the sensitivity of the NMR measurement by a factor of 5 in order to run 2D experiments for structural elucidation of the unknown metabolite. The combination of both MS and NMR results, led unequivocally to the elucidation of the structure as the ether glucuronide of 3-methoxyparacetamol. PMID:15595667

Godejohann, Markus; Tseng, Li-Hong; Braumann, Ulrich; Fuchser, Jens; Spraul, Manfred

2004-11-26

141

Apoptosis in Pneumovirus Infection  

PubMed Central

Pneumovirus infections cause a wide spectrum of respiratory disease in humans and animals. The airway epithelium is the major site of pneumovirus replication. Apoptosis or regulated cell death, may contribute to the host anti-viral response by limiting viral replication. However, apoptosis of lung epithelial cells may also exacerbate lung injury, depending on the extent, the timing and specific location in the lungs. Differential apoptotic responses of epithelial cells versus innate immune cells (e.g., neutrophils, macrophages) during pneumovirus infection can further contribute to the complex and delicate balance between host defense and disease pathogenesis. The purpose of this manuscript is to give an overview of the role of apoptosis in pneumovirus infection. We will examine clinical and experimental data concerning the various pro-apoptotic stimuli and the roles of apoptotic epithelial and innate immune cells during pneumovirus disease. Finally, we will discuss potential therapeutic interventions targeting apoptosis in the lungs.

van den Berg, Elske; van Woensel, Job B.M.; Bem, Reinout A.

2013-01-01

142

Apoptosis and cancer chemotherapy  

Microsoft Academic Search

The explosion of interest in apoptosis amongst cancer biologists has been underpinned by the hope that a mechanistic understanding of cell death will inform our understanding of tumour drug resistance. A framework for drug-induced apoptosis can now be described in which a balance exists between intrinsic and extrinsic survival signals and drug-induced death signals. Pro- and anti-apoptotic signals impact upon

Guy Makin; Caroline Dive

2001-01-01

143

Mitochondrial Dynamics and Apoptosis  

Microsoft Academic Search

\\u000a The dynamic nature of mitochondria is not only important for maintaining normal healthy cells, but is also very important\\u000a in the timely execution of apoptosis. The machinery involved in mediating mitochondrial fission and fusion, namely the large\\u000a GTPases Drp1, OPA1, Mfn1 and Mfn2, can be modulated to either intensify or reduce apoptosis. During the intrinsic\\/mitochondrial\\u000a apoptotic pathway, Drp1 promotes mitochondrial

Megan M. Cleland; Richard J. Youle

144

CoCl2 induces PC12 cells apoptosis through p53 stability and regulating UNC5B.  

PubMed

The receptor uncoordinated 5B (UNC5B) induces apoptosis in the absence of its cognate ligand netrin-1. However, the role of UNC5B in hypoxia-induced apoptosis is not known. Here, we have demonstrated the biological functions of UNC5B in hypoxia-induced apoptosis and related regulatory pathways and examined the effects of UNC5B on p53-dependent apoptosis in PC12 cells under hypoxic conditions. First, we characterized p53-dependent PC12 cell death induced by CoCl2. Our data showed that CoCl2 increased p53 stabilization and transcriptional activity. The downregulation of p53 expression with specific small interfering RNA (p53 siRNA) in CoCl2-treated PC12 cells caused reduction in apoptosis, UNC5B expression, and p21 expression. Moreover, in PC12 cells, ectopic expression of UNC5B significantly enhanced apoptosis, while silencing of UNC5B with siRNA significantly inhibited apoptosis. In addition, netrin-1 significantly inhibited CoCl2-induced p53 stability and UNC5B expression and CoCl2-induced caspase-3 activity and cell death. Collectively, these results demonstrate a novel role for p53 in the control of CoCl2-induced apoptosis through the regulation of UNC5B. PMID:23651544

Lee, Minjae; Kang, Hyereen; Jang, Sung-Wuk

2013-05-04

145

Indole3-carbinol suppresses NF-B and IB kinase activation, causing inhibition of expression of NF-B-regulated antiapoptotic and metastatic gene products and enhancement of apoptosis in myeloid and leukemia cells  

Microsoft Academic Search

Indole-3-carbinol, found in Brassica spe- cies vegetables (such as cabbage, cauli- flower, and brussels spouts), exhibits an- titumor effects through poorly defined mechanisms. Because several genes that regulate apoptosis, proliferation, and me- tastasis are regulated by nuclear fac- tor-B (NF-B), we postulated that indole- 3-carbinol must mediate its activity through NF-B modulation. We demon- strated that indole-3-carbinol suppressed constitutive NF-B

Yasunari Takada; Michael Andreeff; Bharat B. Aggarwal

2005-01-01

146

Apoptosis in metanephric development  

PubMed Central

During metanephric development, non-polarized mesenchymal cells are induced to form the epithelial structures of the nephron following interaction with extracellular matrix proteins and factors produced by the inducing tissue, ureteric bud. This induction can occur in a transfilter organ culture system where it can also be produced by heterologous cells such as the embryonic spinal cord. We found that when embryonic mesenchyme was induced in vitro and in vivo, many of the cells surrounding the new epithelium showed morphological evidence of programmed cell death (apoptosis) such as condensed nuclei, fragmented cytoplasm, and cell shrinking. A biochemical correlate of apoptosis is the transcriptional activation of a calcium-sensitive endonuclease. Indeed, DNA isolated from uninduced mesenchyme showed progressive degradation, a process that was prevented by treatment with actinomycin- D or cycloheximide and by buffering intracellular calcium. These results demonstrate that the metanephric mesenchyme is programmed for apoptosis. Incubation of mesenchyme with a heterologous inducer, embryonic spinal cord prevented this DNA degradation. To investigate the mechanism by which inducers prevented apoptosis we tested the effects of protein kinase C modulators on this process. Phorbol esters mimicked the effects of the inducer and staurosporine, an inhibitor of this protein kinase, prevented the effect of the inducer. EGF also prevented DNA degradation but did not lead to differentiation. These results demonstrate that conversion of mesenchyme to epithelial requires at least two steps, rescue of the mesenchyme from apoptosis and induction of differentiation.

1992-01-01

147

Development of colorimetric solid Phase Extraction (C-SPE) for in-flight Monitoring of spacecraft Water Supplies  

SciTech Connect

Although having recently been extremely successful gathering data on the surface of Mars, robotic missions are not an effective substitute for the insight and knowledge about our solar system that can be gained though first-hand exploration. Earlier this year, President Bush presented a ''new course'' for the U.S. space program that shifts NASA's focus to the development of new manned space vehicles to the return of humans to the moon. Re-establishing the human presence on the moon will eventually lead to humans permanently living and working in space and also serve as a possible launch point for missions into deeper space. There are several obstacles to the realization of these goals, most notably the lack of life support and environmental regeneration and monitoring hardware capable of functioning on long duration spaceflight. In the case of the latter, past experience on the International Space Station (ISS), Mir, and the Space Shuttle has strongly underscored the need to develop broad spectrum in-flight chemical sensors that: (1) meet current environmental monitoring requirements on ISS as well as projected requirements for future missions, and (2) enable the in-situ acquisition and analysis of analytical data in order to further define on-orbit monitoring requirements. Additionally, systems must be designed to account for factors unique to on-orbit deployment such as crew time availability, payload restrictions, material consumption, and effective operation in microgravity. This dissertation focuses on the development, ground testing, and microgravity flight demonstration of Colorimetric Solid Phase Extraction (C-SPE) as a candidate technology to meet the near- and long-term water quality monitoring needs of NASA. The introduction will elaborate further on the operational and design requirements for on-orbit water quality monitoring systems by discussing some of the characteristics of an ''ideal'' system. A description of C-SPE and how the individual components of the platform are combined to satisfy many of these requirements is then presented, along with a literature review on the applications of C-SPE and similar sorption-spectrophotometric techniques. Finally, a brief overview of diffuse reflection spectroscopy and the Kubelka-Munk function, which are used to quantify analytes via C-SPE, is presented.

Daniel Bryan Gazda

2004-12-19

148

Metals and apoptosis: recent developments.  

PubMed

Apoptosis, also known as programmed cell death is a highly regulated and crucial process found in all multicellular organisms. It is not only implicated in regulatory mechanisms of cells, but has been attributed to a number of diseases, i.e. inflammation, malignancy, autoimmunity and neurodegeneration. A variety of toxins can induce apoptosis. Carcinogenic transition metals, viz. cadmium, chromium and nickel promote apoptosis along with DNA base modifications, strand breaks and rearrangements. Generation of reactive oxygen species, accumulation of Ca(2+), upregulation of caspase-3, down regulation of bcl-2, and deficiency of p-53 lead to arsenic-induced apoptosis. In the case of cadmium, metallothionein expression determines the choice between apoptosis and necrosis. Reactive oxygen species (ROS) and p53 contribute in apoptosis caused by chromium. Immuno suppressive mechanisms contribute in lead-induced apoptosis whereas in the case of mercury, p38 mediated caspase activation regulate apoptosis. Nickel kills the cells by apoptotic pathways. Copper induces apoptosis by p53 dependent and independent pathways. Beryllium stimulates the formation of ROS that play a role in Be-induced macrophage apoptosis. Selenium induces apoptosis by producing superoxide that activates p53. Thus, disorders of apoptosis may play a critical role in some of the most debilitating metal-induced afflictions including hepatotoxicity, renal toxicity, neurotoxicity, autoimmunity and carcinogenesis. An understanding of metal-induced apoptosis will be helpful in the development of preventive molecular strategies. PMID:19013355

Rana, Suresh Vir Singh

2008-10-10

149

[Keratocyte apoptosis in keratoconus].  

PubMed

Analysis of 37 corneal disks removed in perforating keratoplasty for stages II-IV keratocone and of 15 corneal disks (control) from subjects dead from mechanical injuries at the age of 17-35 years was carried out. The expression of CD95 receptors on keratocyte membranes was evaluated by indirect immunofluorescent label using rabbit antibodies. Keratocyte apoptosis was evaluated by indirect immunofluorescent labeling of nuclear DNA nucleotides. Estimation of the volumic share of keratocytes expressing CD95 on cell membrane showed it to be almost 8-fold higher and apoptosis index almost 5-fold higher in the keratocone corneal disks than in the control. The results indicate the presence of a Fas-mediated mechanism of keratocyte apoptosis and its manifold predominance in the cornea in keratocone. These results are clinically significant for the choice of pathogenetic therapy of patients with keratocone. PMID:12371322

Sevost'ianov, E N; Giniatullin, R U; Gorskova, E N; Teplova, S N

150

Nucleocytoplasmic transport in apoptosis.  

PubMed

The apoptotic demolition of the nucleus is accomplished by diverse proapoptotic factors, most of which are activated in the cytoplasm and gain access to the nucleoplasm during the cell death process. The nucleus is also the main target for genotoxic insult, a potent apoptotic trigger. Signals generated in the nucleus by DNA damage have to propagate to all cellular compartments to ensure the coordinated execution of cell demise. The nucleocytoplasmic shuttling of signalling and execution factors is thus an integral part of the apoptotic programme. Several proteins implicated in apoptotic cell death have been shown to migrate in and out of the nucleus following apoptosis induction. This review summarises the current knowledge on nucleocytoplasmic trafficking of apoptosis-relevant proteins. The effects of apoptosis induction on the nucleocytoplasmic transport machinery are also discussed. Finally, a potential role of nuclear transport as a critical control point of the apoptotic signal cascade is proposed. PMID:15861192

Ferrando-May, E

2005-10-01

151

Glutathione and apoptosis  

PubMed Central

Apoptosis or programmed cell death represents a physiologically conserved mechanism of cell death that is pivotal in normal development and tissue homeostasis in all organisms. As a key modulator of cell functions, the most abundant non-protein thiol, glutathione (GSH), has important roles in cellular defense against oxidant aggression, redox regulation of proteins thiols and maintaining redox homeostasis that is critical for proper function of cellular processes, including apoptosis. Thus, a shift in the cellular GSH-to-GSSG redox balance in favour of the oxidized species, GSSG, constitutes an important signal that could decide the fate of a cell. The current review will focus on three main areas: (1) general description of cellular apoptotic pathways, (2) cellular compartmentation of GSH and the contribution of mitochondrial GSH and redox proteins to apoptotic signalling and (3) role of redox mechanisms in the initiation and execution phases of apoptosis.

Circu, Magdalena L.; Yee Aw, Tak

2011-01-01

152

Apoptosis in liver disease.  

PubMed

The description of the morphological hallmarks of programmed cell death, apoptosis, in 1972 by Kerr, Wyllie and Currie started a field of research that revolutionized our understanding of cellular proliferation, tissue homeostasis and pathophysiology of many diseases. In the following years, a series of proteins involved in signaling and intracellular death pathways were identified and 30 years later the Noble Prize for physiology and medicine was awarded to S. Brenner, H. R. Horvitz and J. E. Sulston for their discoveries related to describing the mechanisms of cell death (apoptosis). The delineation of the signaling pathways that mediate apoptosis changed the paradigms of understanding in many liver diseases. The most detailed analyzed mode of apoptosis involves a cell surface-based receptor-ligand system. Death receptors are typically members of the tumor necrosis factor-receptor superfamily and comprise an intracellular death domain. Following ligand binding to the receptor, intracellular adapter molecules are recruited to the receptor and subsequently transmit the apoptotic signal. Intracellular organelle-dependent signaling occurs, and effector molecules then augment the receptor-initiated apoptosis process. Cell death and degradation follows the activation of a highly regulated set of cytosolic and nuclear proteases and DNAses. Receptor-independent activation of the apoptotic process can occur as part of the cytotoxicity related to UV radiation, chemotherapeuticals or other DNA-damaging agents through activation of intracellular sensors of cellular integrity, e.g. the tumor suppressor gene p53. In contrast to necrosis, apoptosis is not commonly accompanied by an inflammatory response that causes collateral cell damage. The apoptotic program is highly effective in eliciting cell death and thus must be tightly controlled. This is achieved through continuous integration of pro- and antiapoptotic signals at the individual cell level. Dysregulation of the apoptotic process, resulting in too much or too little cell death, has potentially devastating effects and has been implicated in many forms of liver disease like acute liver failure or hepatocellular carcinoma. This review will focus initially on recent progress in signaling events of hepatocellular apoptosis and subsequently discuss the consequences for the hepatic pathophysiology that involves disarrangement of hepatocellular apoptosis. PMID:16953829

Schattenberg, Jörn M; Galle, Peter R; Schuchmann, Marcus

2006-10-01

153

Autophagy, senescence, and apoptosis.  

PubMed

This chapter presents methods for interrogating the involvement of p53 in signaling to apoptosis, autophagy, and senescence. The well-known association of p53 with the stress response to chemotherapy and radiation is the basis for presenting these approaches. The development of quantitative and efficient in vitro assays has enabled researchers to overcome the limitations of previous methodologies. This chapter provides up-to-date procedures relating to the molecular networks in which the p53 protein has been shown to play a central role that allows damaged cells either to adapt to stress (autophagy and/or senescence) or to progress towards programmed cell death (apoptosis). PMID:23150435

Goehe, Rachel W; Bristol, Molly L; Wilson, Eden N; Gewirtz, David A

2013-01-01

154

Regulation of Apoptosis by Caspases.  

National Technical Information Service (NTIS)

Apoptosis is a cellular suicide mechanism critical for removing cells that may be harmful or no longer needed. Abnormal apoptosis may result in cancer and neural degenerative diseases such as Alzheimer's disease. Caspases are a family of cysteine protease...

J. Yuan

2001-01-01

155

Regulation of Apoptosis by Caspases.  

National Technical Information Service (NTIS)

Caspases are a family of cysteine proteases that play important roles in regulating apoptosis, a genetically encoded cellular suicide mechanism. To determine the mechanism by which caspases regulate apoptosis. We carried out a screen to identify substrate...

J. Yuan

1999-01-01

156

Regulation of SpeB in Streptococcus pyogenes by pH and NaCl: a Model for In Vivo Gene Expression†  

PubMed Central

For a pathogen such as Streptococcus pyogenes, ecological success is determined by its ability to sense the environment and mount an appropriate adaptive transcriptional response. Thus, determining conditions for analyses of gene expression in vitro that are representative of the in vivo environment is critical for understanding the contributions of transcriptional response pathways to pathogenesis. In this study, we determined that the gene encoding the SpeB cysteine protease is up-regulated over the course of infection in a murine soft-tissue model. Conditions were identified, including growth phase, acidic pH, and an NaCl concentration of <0.1 M, that were required for expression of speB in vitro. Analysis of global expression profiles in response to these conditions in vitro identified a set of coregulated genes whose expression patterns showed a significant correlation with that of speB when examined during infection of murine soft tissues. This analysis revealed that a culture medium that promotes high levels of SpeB expression in vitro produced an expression profile that showed significant correlation to the profile observed in vivo. Taken together, these studies establish culture conditions that mimic in vivo expression patterns; that growth phase, pH, and NaCl may mimic relevant cues sensed by S. pyogenes during infection; and that identification of other environmental cues that alter expression of speB in vitro may provide insight into the signals that direct global patterns of gene expression in vivo.

Loughman, Jennifer A.; Caparon, Michael

2006-01-01

157

Sensitive determination of polycyclic aromatic hydrocarbons in water samples by HPLC coupled with SPE based on graphene functionalized with triethoxysilane.  

PubMed

The graphene functionalized with (3-aminopropyl) triethoxysilane was synthesized by a simple hydrothermal reaction and applied as SPE sorbents to extract trace polycyclic aromatic hydrocarbons (PAHs) from environmental water samples. These sorbents possess high adsorption capacity and extraction efficiency due to strong adsorption ability of carbon materials and large specific surface area of nanoparticles, and only 10 mg of sorbents are required to extract PAHs from 100 mL water samples. Several condition parameters, such as eluent and its volume, adsorbent amount, sample volume, sample pH, and sample flow rate, were optimized to achieve good sensitivity and precision. Under the optimized extraction conditions, the method showed good linearity in the range of 1-100 ?g/L, repeatability of the extraction (the RSDs were between 1.8 and 2.9%, n = 6), and satisfactory detection limits of 0.029-0.1 ?g/L. The recoveries of PAHs spiked in environmental water samples ranged from 84.6 to 109.5%. All these results demonstrated that this new SPE technique was a viable alternative to conventional enrichment techniques for the extraction and analysis of PAHs in complex samples. PMID:23335481

Huang, Ke-Jing; Li, Jing; Liu, Yan-Ming; Wang, Lan

2013-01-20

158

iBioSeminar: Apoptosis  

NSDL National Science Digital Library

Apoptosis is a form of programmed cell death that plays important roles during animal development, immune response, elimination of damaged cells, and maintenance of tissue homeostasis. Apoptosis is executed by intracellular proteases named caspases that are activated during the onset of apoptosis by extrinsic and intrinsic pathways.

Xiaodong Wang (Howard Hughes Medical Institute and UT-Southwestern Medical Center;Dept of Biochemistry)

2011-06-08

159

Apoptosis induced by parasitic diseases  

Microsoft Academic Search

Fatalities caused by parasitic infections often occur as a result of tissue injury that results from a form of host-cell death known as apoptosis. However, instead of being pathogenic, parasite-induced apoptosis may facilitate host survival. Consequently, it is of utmost importance to decipher and understand the process and the role of apoptosis induced or controlled by parasites in humans. Despite

Anne-Lise Bienvenu; Elena Gonzalez-Rey; Stephane Picot

2010-01-01

160

Ram ion scattering caused by space shuttle v times B induced differential charging  

SciTech Connect

Observations of secondary, high-inclination ions streams have been reported in the literature. The authors of these previous papers attributed the source of the secondary ions to a disturbed region in the plasma about 10 m form the space shuttle Orbiter. A new theory has been developed which shows how v {times} B induces differential charging on the plasma diagnostics package (PDP) can scatter the ram ion flux. Some of these ions are reflected back to the PDP and may be the source of the observed ion distributions. The effect is unique to large spacecraft; it occurs only when the magnitude of the induced v {times} B potentials are much larger than the electron thermal energy and of the order of the ion ram energy. That the ion streams observed at large angles must have been reflected from the PDP surface is demonstrated with three-dimensional sheath and particle trajectory calculations using the low earth orbit version of the NASA Charging Analyzer Program (NASCAP/LEO).

Katz, I.; Davis, V.A. (S-Cubed Div. of Maxwell Labs., La Jolla, CA (United States))

1987-08-01

161

Ram ion scattering caused by Space Shuttle v x B induced differential charging  

NASA Astrophysics Data System (ADS)

Observations of secondary, high-inclination ions streams have been reported in the literature. The authors of these previous papers attributed the source of the secondary ions to a disturbed region in the plasma about 10 m from the Space Shuttle Orbiter. A new theory has been developed which shows how v x B induced differential charging on the plasma diagnostics package (PDP) can scatter the ram ion flux. Some of these ions are reflected back to the PDP and may be the sorce of the observed ion distributions. The effect is unique to large spacecraft; it occurs only when the magnitude of the induced v x B potentials are much larger than the electron thermal energy and of the order of the ion ram energy. That the ion streams observed at large angles must have been reflected from the PDP surface is demonstrated with three-dimensional sheath and particle trajectory calculations using the low earth orbit version of the NASA Charging Analyzer Program (NASCAP/LEO).

Katz, I.; Davis, V. A.

1987-08-01

162

Contribution of reactive oxygen species to UV-B-induced damage in bacteria.  

PubMed

The present work aimed to identify the reactive oxygen species (ROS) produced during UV-B exposure and their biochemical targets, in a set of bacterial isolates displaying different UV susceptibilities. For that, specific exogenous ROS scavengers (catalase/CAT, superoxide dismutase/SOD, sodium azide and mannitol) were used. Biological effects were assessed from total bacterial number, colony counts and heterotrophic activity (glucose uptake and respiration). DNA strand breakage, ROS generation, oxidative damage to proteins and lipids were used as markers of oxidative stress. Sodium azide conferred a statistically significant protection in terms of lipid oxidation and cell survival, suggesting that singlet oxygen might play an important role in UV-B induced cell inactivation. Mannitol exerted a significant protection against DNA strand breakage and protein carbonylation, assigning hydroxyl radicals to DNA and protein damage. The addition of exogenous CAT and SOD significantly protected the capacity for glucose uptake and respiration, suggesting that superoxide and H(2)O(2) are involved in the impairment of activity during UV-B exposure. The observation that amendment with ROS scavengers can sometimes also exert a pro-oxidant effect suggests that the intracellular oxidant status of the cell ultimately determines the efficiency of antioxidant defenses. PMID:23026387

Santos, Ana L; Gomes, Newton C M; Henriques, Isabel; Almeida, Adelaide; Correia, António; Cunha, Ângela

2012-09-05

163

NF-?B-Inducing Kinase Increases Renal Tubule Epithelial Inflammation Associated with Diabetes  

PubMed Central

The impact of increased NF-?B-inducing kinase (NIK), a key component of the NF-?B activation pathways, on diabetes-induced renal inflammation remains unknown. We overexpressed NIK wild type (NIKwt) or kinase-dead dominant negative mutants (NIKdn) in HK-2 cells and demonstrated that RelB and p52, but not RelA, abundance and DNA binding increased in nuclei of NIKwt but not NIKdn overexpressed cells, and this corresponded with increases in multiple proinflammatory cytokines. Since TRAF3 negatively regulates NIK expression, we silenced TRAF3 by >50%; this increased nuclear levels of p52 and RelB, and transcript levels of proinflammatory cytokines and transcription factors. In HK-2 cells and mouse primary proximal tubule epithelial cells treated with methylglyoxal-modified albumin, multiple proinflammatory cytokines and NIK were increased in association with increased nuclear RelB and p52. These observations indicate that NIK regulates proinflammatory responses of renal proximal tubular epithelial cells via mechanisms involving TRAF3 and suggest a role for NF-?B noncanonical pathway activation in modulating diabetes-induced inflammation in renal tubular epithelium.

Zhao, Yanhua; Banerjee, Srijita; LeJeune, Wanda S.; Choudhary, Sanjeev; Tilton, Ronald G.

2011-01-01

164

Brevenal Inhibits Pacific Ciguatoxin-1B-Induced Neurosecretion from Bovine Chromaffin Cells  

PubMed Central

Ciguatoxins and brevetoxins are neurotoxic cyclic polyether compounds produced by dinoflagellates, which are responsible for ciguatera and neurotoxic shellfish poisoning (NSP) respectively. Recently, brevenal, a natural compound was found to specifically inhibit brevetoxin action and to have a beneficial effect in NSP. Considering that brevetoxin and ciguatoxin specifically activate voltage-sensitive Na+ channels through the same binding site, brevenal has therefore a good potential for the treatment of ciguatera. Pacific ciguatoxin-1B (P-CTX-1B) activates voltage-sensitive Na+ channels and promotes an increase in neurotransmitter release believed to underpin the symptoms associated with ciguatera. However, the mechanism through which slow Na+ influx promotes neurosecretion is not fully understood. In the present study, we used chromaffin cells as a model to reconstitute the sequence of events culminating in ciguatoxin-evoked neurosecretion. We show that P-CTX-1B induces a tetrodotoxin-sensitive rise in intracellular Na+, closely followed by an increase in cytosolic Ca2+ responsible for promoting SNARE-dependent catecholamine secretion. Our results reveal that brevenal and ?-naphtoyl-brevetoxin prevent P-CTX-1B secretagogue activity without affecting nicotine or barium-induced catecholamine secretion. Brevenal is therefore a potent inhibitor of ciguatoxin-induced neurotoxic effect and a potential treatment for ciguatera.

Mattei, Cesar; Alvarez, Martha; Benoit, Evelyne; Bourdelais, Andrea J.; Lewis, Richard J.; Baden, Daniel G.; Molgo, Jordi; Meunier, Frederic A.

2008-01-01

165

Apoptosis in neurodegenerative disorders  

Microsoft Academic Search

Neuronal death underlies the symptoms of many human neurological disorders, including Alzheimer's, Parkinson's and Huntington's diseases, stroke, and amyotrophic lateral sclerosis. The identification of specific genetic and environmental factors responsible for these diseases has bolstered evidence for a shared pathway of neuronal death — apoptosis — involving oxidative stress, perturbed calcium homeostasis, mitochondrial dysfunction and activation of cysteine proteases called

Mark P. Mattson

2000-01-01

166

Biomarkers of apoptosis  

Microsoft Academic Search

Within the era of molecularly targeted anticancer agents, it has become increasingly important to provide proof of mechanism as early on as possible in the drug development cycle, especially in the clinic. Selective activation of apoptosis is often cited as one of the major goals of cancer chemotherapy. Thus, the present minireview focuses on a discussion of the pros and

T H Ward; J Cummings; E Dean; A Greystoke; J M Hou; A Backen; M Ranson; C Dive

2008-01-01

167

Apoptosis of Multiple Myeloma  

PubMed Central

Multiple myeloma (MM) is a malignancy of terminally differentiated plasma cells. MM cells localize to the bone marrow, where cell adhesion–mediated autocrine or paracrine activation of various cytokines, such as interleukin 6, insulin-like growth factor 1, and interferon ?, results in their accumulation mainly because of loss of critical apoptotic controls. Resistance to apoptosis, a genetically regulated cell death process, may play a critical role in both pathogenesis and resistance to treatment of MM. Abnormalities in regulation and execution of apoptosis can contribute to tumor initiation, progression, as well as to tumor resistance to various therapeutic agents. Apoptosis is executed via 2 main pathways that lead to activation of caspases: the death receptor (extrinsic) pathway and the mitochondrial (intrinsic) pathway. Ionizing radiation and chemotherapeutic agents act primarily through the intrinsic pathway, in which mitochondria play the central role. Various therapeutic modalities that are effective in MM modulate levels of the proapoptotic and antiapoptotic Bcl-2 family of proteins and of inhibitors of apoptosis, expression of which is primarily regulated by p53, nuclear factor ?B, and STAT (signal transducers and activators of transcription) factors. This review focuses on the key concepts and some of the most recent studies of signaling pathways regulated in MM and summarizes what is known about the clinical role of these pathways.

Oancea, Marcela; Mani, Aruna; Hussein, Mohamad A; Almasan, Alexandru

2005-01-01

168

Reaper-Induced Apoptosis.  

National Technical Information Service (NTIS)

Reaper is a central regulator of apoptosis in the fly, Drosophila melanogaster. At the start of this proposal our laboratory identified what was believed to be a pro-apoptotic human homolog of Reaper. This was of extreme interest as no true Reaper homolog...

J. Perry

2005-01-01

169

NF-?B inducing kinase (NIK) modulates melanoma tumorigenesis by regulating expression of pro-survival factors through the ?-catenin pathway  

PubMed Central

Nuclear factor-?B (NF-?B) inducing kinase (NIK) is a MAP3K that regulates the activation of NF-?B. NIK is often highly expressed in tumor cells, including melanoma, but the significance of this in melanoma progression has been unclear. Tissue microarray analysis of NIK expression reveals that dysplastic nevi (n=22), primary (n=15) and metastatic melanoma (n=13) lesions showed a statistically significant elevation in NIK expression when compared to benign nevi (n=30). Moreover, when shRNA techniques were used to knock-down NIK, the resultant NIK-depleted melanoma cell lines exhibited decreased proliferation, increased apoptosis, and reduced tumor growth in a mouse xenograft model. As expected, when NIK was depleted there was decreased activation of the non-canonical NF-?B pathway, while canonical NF-?B activation remained intact. NIK depletion also resulted in reduced expression of genes that contribute to tumor growth, including CXCR4, c-MYC and c-MET, and pro-survival factors such as BCL2 and survivin. These changes in gene expression are not fully explained by the attenuation of the non-canonical NF-?B pathway. Shown here for the first time is the demonstration that NIK modulates ?-catenin mediated transcription to promote expression of survivin. NIK-depleted melanoma cells exhibited down-regulation of survivin as well as other ?-catenin regulated genes including c-MYC, c-MET and CCND2. These data indicate that NIK mediates both ?-catenin and NF-?B regulated transcription to modulate melanoma survival and growth. Thus, NIK may be a promising therapeutic target for melanoma.

Thu, Yee Mon; Su, Yingjun; Yang, Jinming; Splittgerber, Ryan; Na, Songqing; Boyd, Alan; Mosse, Claudio; Simons, Christopher; Richmond, Ann

2011-01-01

170

Characterization of Polymyxin B-Induced Nephrotoxicity: Implications for Dosing Regimen Design  

PubMed Central

The increasing prevalence of multidrug-resistant Gram-negative infections has led to renewed interest in the use of systemic polymyxin B. However, the nephrotoxic properties of polymyxin B are still poorly understood. The objective of this study was to characterize nephrotoxicity associated with polymyxin B, with an emphasis on examining the impact of dosing frequencies on the onset of nephrotoxicity. Sprague-Dawley rats were divided into two groups and administered the same total daily dose of polymyxin B subcutaneously but with different dosing frequencies (either 20 mg/kg of body weight every 24 h [q24h] or 5 mg/kg q6h). Drug concentrations in renal tissue were compared between the two groups at 24 h. Kidney tissues were harvested at 48 h and compared histologically. Serum creatinine was measured daily for up to 10 days, and nephrotoxicity was defined as a significant elevation in serum creatinine (?2× baseline). Kaplan-Meier analysis was used to compare the onset of nephrotoxicity. Polymyxin B-induced nephrotoxicity manifested as elevation in serum creatinine and acute tubular necrosis. Extensive injury of the proximal tubules was observed. The lesions were more severe and higher drug concentrations were achieved in the kidneys of the q6h dosing group. The q24h dosing group experienced a more gradual onset of nephrotoxicity, which could be attributed to the lower kidney tissue drug concentrations (48.5 ± 17.4 ?g/g versus 92.1 ± 18.1 ?g/g of polymyxin B1, P = 0.04). Preferential accumulation of polymyxin B in the kidneys suggests that uptake to renal cells is a nonpassive process and q24h dosing was less nephrotoxic than q6h dosing.

Abdelraouf, Kamilia; Braggs, Kirk H.; Yin, Taijun; Truong, Luan D.; Hu, Ming

2012-01-01

171

Shaping organisms with apoptosis.  

PubMed

Programmed cell death is an important process during development that serves to remove superfluous cells and tissues, such as larval organs during metamorphosis, supernumerary cells during nervous system development, muscle patterning and cardiac morphogenesis. Different kinds of cell death have been observed and were originally classified based on distinct morphological features: (1) type I programmed cell death (PCD) or apoptosis is recognized by cell rounding, DNA fragmentation, externalization of phosphatidyl serine, caspase activation and the absence of inflammatory reaction, (2) type II PCD or autophagy is characterized by the presence of large vacuoles and the fact that cells can recover until very late in the process and (3) necrosis is associated with an uncontrolled release of the intracellular content after cell swelling and rupture of the membrane, which commonly induces an inflammatory response. In this review, we will focus exclusively on developmental cell death by apoptosis and its role in tissue remodeling. PMID:23449394

Suzanne, M; Steller, H

2013-03-01

172

23,24-Dihydrocucurbitacin B induces G 2\\/M cell-cycle arrest and mitochondria-dependent apoptosis in human breast cancer cells (Bcap37)  

Microsoft Academic Search

23,24-Dihydrocucurbitacin B (DHCB), a cucurbitacin-derived compound known to posses anticancer and anti-inflammatory activities. In this study, DHCB, isolated from roots of Trichosanthes kirilowli which is a traditional Chinese herb medicine used as treatments for cancer and other diseases, has been found to inhibit the proliferation of human cancer cell lines Bcap37, HeLa, SW620, SMMC-7721, K562 and MCF-7 in a dose-

Lu Yang; Shihua Wu; Qiuhui Zhang; Feiyan Liu; Ping Wu

2007-01-01

173

Response surface methodology applied to SPE for the determination of ibuprofen in various types of water samples.  

PubMed

Over the last few years, there has been a growing concern about the presence of pharmaceuticals in the environment. The main objective of this study was to develop and validate an SPE method using surface response methodology for the determination of ibuprofen in different types of water samples. The influence of sample pH and sample volume on the ibuprofen recovery was studied. The effect of each studied independent variable is pronounced on the dependent variable (ibuprofen recovery). Good selectivity, extraction efficiency, and precision were achieved using 600 mL of sample volume with the pH adjusted to 2.2. LC with fluorescence detection was employed. The optimized method was applied to 20 water samples from the North and South of Portugal. PMID:23907765

Paíga, Paula; Delerue-Matos, Cristina

2013-08-28

174

Mitochondrial control of apoptosis  

Microsoft Academic Search

The apoptotic process can be subdivided into three phases: a death-stimulus-dependent, heterogeneous induction phase, a common effector phase during which the ‘decision to die’ is taken, and a common degradation phase during which cells acquire the biochemical and morphological features of end-stage apoptosis. Here, Guido Kroemer, Naoufal Zamzami and Santos Susin discuss the implication of mitochondrial events in the apoptotic

Guido Kroemer; Naoufal Zamzami; Santos A. Susin

1997-01-01

175

Mitochondria and Apoptosis  

NSDL National Science Digital Library

A variety of key events in apoptosis focus on mitochondria, including the release of caspase activators (such as cytochrome c), changes in electron transport, loss of mitochondrial transmembrane potential, altered cellular oxidation-reduction, and participation of pro- and antiapoptotic Bcl-2 family proteins. The different signals that converge on mitochondria to trigger or inhibit these events and their downstream effects delineate several major pathways in physiological cell death.

Douglas Green (La Jolla Institute for Allergy and Immunology;); John Reed (Burnham Institute;)

1998-08-28

176

endoreduplication, and delayed apoptosis  

Microsoft Academic Search

A c-Jun N-terminal kinase inhibitor, SP600125, strongly inhibits cell proliferation in many human cancer cells by blocking cell-cycle progression and inducing apoptosis. Despite extensive study, the mechanism by which SP600125 inhibits mitosis-related effects in human leukemia cells remains unclear. This present paper aims to investigate the effects of SP600125 on the inhibition of cell proliferation and the cell cycle and

Dong-Oh Moon; Mun-Ock Kim; Chang-Hee Kang; Jae-Dong Lee; Yung Hyun Choi

177

Simultaneous online SPE-HPLC-MS/MS analysis of docetaxel, temsirolimus and sirolimus in whole blood and human plasma.  

PubMed

Docetaxel and temsirolimus are some of the most used drugs in a wide range of solid tumors. In preclinical studies, mTOR inhibitors such as temsirolimus have demonstrated synergistic cytotoxic effects with taxanes providing the rationale for combination studies. These anticancer agents exhibit a narrow therapeutic concentration range and due to their high inter- and intra-individual pharmacokinetic variability, therapeutic dose monitoring by highly sensitive methods as LC-MS/MS are important for clinical research. Therefore, the aim of this study was to develop and validate a sensitive, fast and convenient method for the simultaneous identification and quantification of docetaxel, temsirolimus and its main metabolite, sirolimus, using paclitaxel, another anticancer drug, as the internal standard. These analytes were quantified by an integrated online solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) system. Separation was performed on a Zorbax eclipse XDB-C8 (150mm×4.6mm, 5?m) column. The mass spectrometer tandem quadruple detector was equipped with jet stream electrospray ionization, monitored in multiple reactions monitoring (MRM) and operated in positive mode. A combination of protein precipitation with methanol/zinc sulphate (70:30) (v/v) and online SPE using a Zorbax eclipse plus C8 (12.5mm×4.6mm, 5?m) cartridge was used to extract the compounds. This method allows the use of the same reagents, sample treatment and analytical technique independently of whether the samples are whole blood or plasma. The method has been successfully validated and applied to real samples. It is a suitable method for dose adjustment and for evaluating potential drug interactions during combined treatments. PMID:23422405

Navarrete, Alicia; Martínez-Alcázar, M Paz; Durán, Ignacio; Calvo, Emiliano; Valenzuela, Belén; Barbas, Coral; García, Antonia

2013-01-28

178

Jolkinolide B from Euphorbia fischeriana Steud induces in human leukemic cells apoptosis via JAK2/STAT3 pathways.  

PubMed

Jolkinolide B from the roots of Euphorbia fischeriana Steud exhibits significant antitumor activities against several tumor lines. Previous study has shown that Jolkinolide B could induce apoptosis in human leukemia cells. However, the exact mechanism and signaling pathway involved in Jolkinolide B-induced apoptosis have not been fully elucidated. In the present study, we found that Jolkinolide B reduced cell viability and induced apoptosis in dose- and time-dependent manner in human leukemic HL-60 and THP-1 cells. The induction of apoptosis was accompanied by the downregulation of JAK2/STAT3. Our results also suggest that expression of Bcl-2 and mitochondrial cytochrome c was dosedependently reduced following Jolkinolide B-treated THP-1 and HL-60 cells, whereas Jolkinolide B up-regulated the expression of Bax and cytosolic cytochrome c. Moreover, we observed that Jolkinolide B treatment resulted in activation of caspase-3, -8, and -9. JSI-124, a STAT-3 inhibitor, was able to block the negative effect of Jolkinolide B on cell apoptosis. Taken together, our study for the first time suggests that Jolkinolide B is able to enhance apoptosis of human leukemic HL-60 and THP-1 cells, at least in part, through downregulation of JAK2/STAT3 and bcl-2, and upregulation of Bax and cytosolic cytochrome c. Moreover, the triggering of caspase-3, -8, and -9 activation mediated apoptotic induction. PMID:23253949

Wang, Jia-He; Zhang, Ke; Niu, Hui-Yan; Shu, Lin-Hua; Yue, Dong-Mei; Li, Dong- Yang; He, Ping

2013-03-01

179

Quechers methodologies as an alternative to solid phase extraction (SPE) for the determination and characterization of residues of cephalosporins in beef muscle using LC-MS/MS.  

PubMed

This work was focused on the comparison of two clean-up methods to be used for the simultaneous determination of seven cephalosporins in cow muscle. In particular, the performance of novel dispersive solid phase extraction (d-SPE) procedures based on QuEChERS methodologies was assessed and compared with conventional SPE. The separation and detection of the analytes using both methods was carried out by LC-MS/MS to reach enough sensitivity to be compatible with the detection of the maximum residue limits (MRL) of cephalosporins as regulated by EU directives. The optimization of the clean-up step relied on experimental design in order to find the most suitable conditions with a reduced number of assays. Besides, multi-objective responses were used to reach an overall compromise in the recovery of all analytes simultaneously. The validation of the two methods was done according to the Directive 2002/657/EC. Linearity, decision limit, detection capability, detection and quantification limits (4-50 ?g kg?¹), precision (RSD less than 15% except for PIR) and recoveries were determined and adequate results with comparable values using QuEChERS and SPE methodologies. LOQ were better for SPE method (0.1-10 ?g kg?¹) but both methods show LOQ below MRL values. Precision was slightly better for the QuEChERS method, that also presents better recoveries, higher than 85% except for cephalexin. PMID:22658467

Pérez-Burgos, R; Grzelak, E M; Gokce, G; Saurina, J; Barbosa, J; Barrón, D

2012-05-06

180

Development and application of a new on-line SPE system combined with LC-MS/MS detection for high throughput direct analysis of pharmaceutical compounds in plasma.  

PubMed

A technique using a fully automated on-line solid phase extraction (SPE) system (Symbiosis, Spark Holland) combined with liquid chromatography (LC)-mass spectrometry (MS/MS) has been investigated for fast bioanalytical method development, method validation and sample analysis using both conventional C18 and monolithic columns. Online SPE LC-MS/MS methods were developed in the automated mode for the quantification of model compounds (propranolol and diclofenac) directly in rat plasma. Accuracy and precision using online SPE LC-MS/MS with conventional C18 and monolithic columns were in the range of 88-111% and 0.5-14%, respectively. Total analysis cycle time of 4 min per sample was demonstrated using the C18 column. Monolithic column allowed for 2 min total cycle time without compromising the quality and validation criteria of the method. Direct plasma sample injection without on-line SPE resulted in poor accuracy and precision in the range of 41-108% and 3-81%. Furthermore, the increase in back pressure resulted in column damage after the injection of only 60 samples. PMID:16008047

Alnouti, Yazen; Srinivasan, Karthik; Waddell, David; Bi, Honggang; Kavetskaia, Olga; Gusev, Arkady I

2005-07-01

181

Effect of SPE-like proton or photon radiation on the kinetics of mouse peripheral blood cells and radiation biological effectiveness determinations.  

PubMed

Exploration missions outside low-Earth orbit are being planned; therefore, it is critical to understand the risk astronauts would be exposed to in the space environment, especially during extravehicular activities (EVAs). Reductions in white blood cell (WBC) numbers can occur as a result of exposure to solar particle event (SPE) radiation. The aim of the present study was to determine the duration of the effects on blood cell numbers from exposure to a single whole-body dose of SPE-like proton radiation or photon radiation as well as to determine the radiation biological effectiveness (RBE) values at those times when radiation exposure causes blood cell numbers to experience the most critical effects when using mice as a model. Our results indicate that both types of radiation cause significant reductions in the numbers of all blood cell types at different times post-irradiation. The RBE values were not significantly different from 1.0. These results indicate that the risk estimations for astronauts from exposure of mice to SPE-like proton radiation are comparable to those previously made for doses of standard reference radiations, suggesting that countermeasures should be developed for the decreases in blood cell counts observed following the exposure of mice to SPE radiation. PMID:23980767

Romero-Weaver, A L; Wan, X S; Diffenderfer, E S; Lin, L; Kennedy, A R

2013-06-01

182

Determination of crystal violet in seawater and seafood samples through off-line molecularly imprinted SPE followed by HPLC with diode-array detection.  

PubMed

A highly selective sample cleanup procedure combined with molecularly imprinted SPE was developed for the isolation of crystal violet from seawater and seafood samples. The molecularly imprinted polymer was prepared using crystal violet as the template molecule, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. The crystal violet-imprinted polymer was used as the selective sorbent for the SPE of crystal violet. An off-line molecularly imprinted SPE method followed by HPLC with diode-array detection for the analysis of crystal violet was also established. Good linearity on the molecularly imprinted SPE columns was obtained from 0 to 200 ?g/L (R(2) > 0.99). The result demonstrated that the proposed method can be used for the direct determination of crystal violet in seawater and seafood samples. Finally, five samples were analyzed and the following crystal violet concentrations were obtained: 0.92 and 0.52 ?g/L in two seawater samples, as well as 0.36 and 0.27 ?g/kg in two seafood samples. There is no crystal violet detected in the third seawater sample. PMID:23390113

Lian, Ziru; Wang, Jiangtao

2013-02-06

183

Lysine 394 is a novel Rad6B-induced ubiquitination site on beta-catenin.  

PubMed

The ubiquitin conjugating enzyme Rad6B is overexpressed in breast cancer and induces ?-catenin transcriptional activation and stabilization via K63-linked polyubiquitination. Here we identify ?-catenin and Rad6B interacting regions, identify potential Rad6B ubiquitination sites in ?-catenin, and characterize their breast cancer tissue expression. ?-catenin and Rad6B colocalize in breast carcinoma and coimmunoprecipitate from MDA-MB-231 cells. Pull-down assays using GST-?-catenin and His-Rad6B deletion mutants identified amino acids 131-181 and 50-116, respectively, as necessary for their interaction. Ubiquitination assays using ?-catenin deletion mutants mapped Rad6B-induced ubiquitination within ?-catenin 181-422 encompassing Armadillo repeats 2-7. Lysine to arginine mutations within repeats 5-7 identified K394 as the major Rad6B ubiquitination site in vitro and in vivo, and confirmed by Rad6B ubiquitination of a ?-catenin peptide encompassing K394. Ubiquitination of wild type- but not K394R-?-catenin was decreased by Rad6B silencing. Compared to wild type-, K312R-, K335R-, K345R-, or K354R-?-catenin, K394R mutation caused ~50% drop in TOP/Flash activity in Wnt-silent MCF-7 cells. Consistent with these data, expression of Rad6B, itself a ?-catenin/TCF transcriptional target, was also reduced in K394R-?-catenin transfected cells. Steady-state K394R-?-catenin levels are decreased compared to wild type-?-catenin. The decreased expression is not due to proteasomal degradation as treatment with MG132 failed to rescue its levels. Lymph node-positive breast carcinomas express higher levels of Rad6 protein and Rad6 activity, and K63-linked ubiquitinated ?-catenin than reduction mammoplasties. These data suggest that K394 is a novel site of ?-catenin ubiquitination that may be important for the stability and activity of ?-catenin in breast cancer. PMID:22705350

Gerard, Brigitte; Sanders, Matthew A; Visscher, Daniel W; Tait, Larry; Shekhar, Malathy P V

2012-06-15

184

Ribosome Inactivating Proteins and Apoptosis  

Microsoft Academic Search

\\u000a Ribosome inactivating proteins (RIPs) are RNA N-glycosidases which potently inhibit translation by inactivating ribosomes. RIPs have also been shown to possess the ability\\u000a to induce apoptosis. A number of RIPs from different sources have been used to study the mechanism of apoptosis induction.\\u000a However, it is being observed that these toxins trigger apoptosis in different cell types via different mechanisms;

Deepa Sikriwal; Janendra K. Batra

185

Dispersal of Group A Streptococcal Biofilms by the Cysteine Protease SpeB Leads to Increased Disease Severity in a Murine Model  

PubMed Central

Group A Streptococcus (GAS) is a Gram-positive human pathogen best known for causing pharyngeal and mild skin infections. However, in the 1980's there was an increase in severe GAS infections including cellulitis and deeper tissue infections like necrotizing fasciitis. Particularly striking about this elevation in the incidence of severe disease was that those most often affected were previously healthy individuals. Several groups have shown that changes in gene content or regulation, as with proteases, may contribute to severe disease; yet strains harboring these proteases continue to cause mild disease as well. We and others have shown that group A streptococci (MGAS5005) reside within biofilms both in vitro and in vivo. That is to say that the organism colonizes a host surface and forms a 3-dimensional community encased in a protective matrix of extracellular protein, DNA and polysaccharide(s). However, the mechanism of assembly or dispersal of these structures is unclear, as is the relationship of these structures to disease outcome. Recently we reported that allelic replacement of the streptococcal regulator srv resulted in constitutive production of the streptococcal cysteine protease SpeB. We further showed that the constitutive production of SpeB significantly decreased MGAS5005?srv biofilm formation in vitro. Here we show that mice infected with MGAS5005?srv had significantly larger lesion development than wild-type infected animals. Histopathology, Gram-staining and immunofluorescence link the increased lesion development with lack of disease containment, lack of biofilm formation, and readily detectable levels of SpeB in the tissue. Treatment of MGAS5005?srv infected lesions with a chemical inhibitor of SpeB significantly reduced lesion formation and disease spread to wild-type levels. Furthermore, inactivation of speB in the MGAS5005?srv background reduced lesion formation to wild-type levels. Taken together, these data suggest a mechanism by which GAS disease may transition from mild to severe through the Srv mediated dispersal of GAS biofilms.

Connolly, Kristie L.; Roberts, Amity L.; Holder, Robert C.; Reid, Sean D.

2011-01-01

186

Pre-Shot Simulations of Far-Field Ground Motions for the Source Physics Experiment (SPE) Explosions at the Climax Stock, Nevada National Security Site  

SciTech Connect

The Source Physics Experiment (SPE) will involve a series of explosions in various geologic and emplacement conditions to validate numerical simulation methods to predict behavior of seismic wave excitation and propagation for nuclear test monitoring. The first SPE's currently underway involve explosions in the Climax Stock (granitic geology) at the Nevada National Security Site (NNSS). Detailed geologic data and published material properties for the major lithologic units of the NNSS and surrounding region were used to build three-dimensional models for seismic wave propagation simulations. The geologic structure near the SPE shot point is quite varied including granitic, carbonate, tuff and alluvium lithologies. We performed preliminary ground motion simulations for a near-source domain covering 8 km x 8 km at the surface centered on the shot point to investigate various source and propagation effects using WPP, LLNL's anelastic seismic wave finite difference code. Simulations indicate that variations in wave propagation properties of the sub-surface will generate strongly path-dependent response once the energy has left the relatively small granitic geology of the near-surface Climax Stock near the SPE shot point. Rough topography to the north and west of SPE shot point causes additional complexity in the signals including energy on the transverse components. Waves propagate much faster through the granitic and carbonate formations and slower through the tuff and alluvium. Synthetic seismograms for a pure explosion source in a 3D geologic structure show large amplitudes on transverse component. For paths to the south sampling the granite, tuff and alluvium lithologies transverse component amplitudes are as high as 50% of that on the vertical and radial components.

Rodgers, A J; Wagoner, J; Petersson, N A; Sjogreen, B

2010-11-07

187

[Mitochondria and apoptosis].  

PubMed

It is now accepted that mitochondria are endosymbionts, originated in aerobic bacteria which were integrated by the ancestor of eukaryotic cells. A part of the apoptotic machinery could exist in unicellular eukaryotic and some controlling apoptosis components might be present in prokaryotes. It is therefore possible that the mechanism originally involved in the maintenance of the symbiosis between the bacterial ancestor of the mitochondria and the host cell precursor of eukaryotes, provided the basis for the actual mechanism controlling cell survival. Metazoans would have improved this possibility by connecting to the mitochondria as principal effector of cellular death to the pathways of signal transduction. A variety of events appoint to the mitochondria as principal effector of the apoptosis. This including the release caspase activators (cytochrome c), changes in electron transport, loss of mitochondrial transmembrane potential, altered cellular oxidation-reduction, and participation of pro and antiapoptotic Bcl-2 proteins. The different signals that converge on mitochondria for activation or inhibition of these events, delineate several pathways in the physiology of the cellular death. PMID:12945496

Arvelo, Francisco

2002-01-01

188

Apoptosis Resistance in Endometriosis  

PubMed Central

Introduction In a cytological analysis of endometriotic lesions neither granulocytes nor cytotoxic T-cells appear in an appreciable number. Based on this observation we aimed to know, whether programmed cell death plays an essential role in the destruction of dystopic endometrium. Disturbances of the physiological mechanisms of apoptosis, a persistence of endometrial tissue could explain the disease. Another aspect of this consideration is the proliferation competence of the dystopic mucous membrane. Methods Endometriotic lesions of 15 patients were examined through a combined measurement of apoptosis activity with the TUNEL technique (terminal deoxyribosyltransferase mediated dUTP Nick End Labeling) and the proliferation activity (with the help of the Ki-67-Antigens using the monoclonal antibody Ki-S5). Results Twelve out of 15 women studied showed a positive apoptotic activity of 3-47% with a proliferation activity of 2-25% of epithelial cells. Therefore we concluded that the persistence of dystopic endometrium requires proliferative epithelial cells from middle to lower endometrial layers. Conclusion A dystopia misalignment of the epithelia of the upper layers of the functionalism can be rapidly eliminated by apoptotic procedures.

Salmassi, Ali; Acar-Perk, Bengi; Schmutzler, Andreas G.; Koch, Kerstin; Pungel, Frank; Jonat, Walter; Mettler, Liselotte

2011-01-01

189

Malnutrition-induced macrophage apoptosis  

Microsoft Academic Search

Background. Human and murine studies suggest protein-calorie malnutrition (PCM) results in significant host immunosuppression resulting in increased morbidity and mortality. Apoptosis has been implicated as an important mediator in the immunosuppression observed in several disease states. This study was designed to characterize macrophage apoptosis in a murine model of PCM and investigate components that regulate the apoptotic process, such as

David E. Rivadeneira; Stephen R. Grobmyer; Hassan A. Naama; Peter J. Mackrell; Juan R. Mestre; Philip P. Stapleton; John M. Daly

2001-01-01

190

BARC: A Novel Apoptosis Regulator.  

National Technical Information Service (NTIS)

Breast cancers arise due to an imbalance in cell production relative to cell turnover, resulting in a net accumulation of abnormal cells. Cell turnover is normally achieved in the body by a process known as apoptosis. Defects in apoptosis mechanisms commo...

C. Jin J. C. Reed H. Zhang H. J. Chae

2005-01-01

191

Metals and apoptosis: Recent developments  

Microsoft Academic Search

Apoptosis, also known as programmed cell death is a highly regulated and crucial process found in all multicellular organisms. It is not only implicated in regulatory mechanisms of cells, but has been attributed to a number of diseases, i.e. inflammation, malignancy, autoimmunity and neurodegeneration. A variety of toxins can induce apoptosis. Carcinogenic transition metals, viz. cadmium, chromium and nickel promote

Suresh Vir Singh Rana

2008-01-01

192

Apoptosis and the Airway Epithelium  

PubMed Central

The airway epithelium functions as a barrier and front line of host defense in the lung. Apoptosis or programmed cell death can be elicited in the epithelium as a response to viral infection, exposure to allergen or to environmental toxins, or to drugs. While apoptosis can be induced via activation of death receptors on the cell surface or by disruption of mitochondrial polarity, epithelial cells compared to inflammatory cells are more resistant to apoptotic stimuli. This paper focuses on the response of airway epithelium to apoptosis in the normal state, apoptosis as a potential regulator of the number and types of epithelial cells in the airway, and the contribution of epithelial cell apoptosis in important airways diseases.

White, Steven R.

2011-01-01

193

Uncertainty Estimation for the Determination of Ni, Pb and Al in Natural Water Samples by SPE-ICP-OES  

NASA Astrophysics Data System (ADS)

In this paper we propose uncertainty estimation for the analytical results we obtained from determination of Ni, Pb and Al by solidphase extraction and inductively coupled plasma optical emission spectrometry (SPE-ICP-OES). The procedure is based on the retention of analytes in the form of 8-hydroxyquinoline (8-HQ) complexes on a mini column of XAD-4 resin and subsequent elution with nitric acid. The influence of various analytical parameters including the amount of solid phase, pH, elution factors (concentration and volume of eluting solution), volume of sample solution, and amount of ligand on the extraction efficiency of analytes was investigated. To estimate the uncertainty of analytical result obtained, we propose assessing trueness by employing spiked sample. Two types of bias are calculated in the assessment of trueness: a proportional bias and a constant bias. We applied Nested design for calculating proportional bias and Youden method to calculate the constant bias. The results we obtained for proportional bias are calculated from spiked samples. In this case, the concentration found is plotted against the concentration added and the slop of standard addition curve is an estimate of the method recovery. Estimated method of average recovery in Karaj river water is: (1.004±0.0085) for Ni, (0.999±0.010) for Pb and (0.987±0.008) for Al.

Ghorbani, A.; Farahani, M. Mahmoodi; Rabbani, M.; Aflaki, F.; Waqifhosain, Syed

2008-01-01

194

Ionic-liquid-functionalized magnetic particles as an adsorbent for the magnetic SPE of sulfonylurea herbicides in environmental water samples.  

PubMed

In this paper, a new ionic-liquid-functionalized magnetic material was prepared based on the immobilization of an ionic liquid on silica magnetic particles that could be successfully used as an adsorbent for the magnetic SPE of five sulfonylurea herbicides (bensulfuron-methyl, prosulfuron, pyrazosulfuron-ethyl, chlorimuron-ethyl and triflusulfuron-methyl) from environmental water samples. The main parameters affecting the extraction efficiency such as desorption conditions, sample pH, extraction time and so on, were optimized using the Taguchi method. Good linearities were obtained with correlation coefficients ranging from 0.9992 to 0.9999 in the concentration range of 0.1-50 ?g L(-1) and the LODs were 0.053-0.091 ?g L(-1) . Under the optimum conditions, the enrichment factors of the method were 1155-1380 and the recoveries ranged from 77.8 to 104.4%. The proposed method was reliable and could be applied to the residue analysis of sulfonylurea herbicides in environmental water samples (tap, reservoir and river). PMID:23894051

He, Zeying; Liu, Donghui; Zhou, Zhiqiang; Wang, Peng

2013-08-27

195

Selective preconcentration of volatile mercaptans in small SPE cartridges: quantitative determination of trace odor-active polyfunctional mercaptans in wine.  

PubMed

A general procedure for the selective preconcentration and purification of mercaptans has been developed. Mercaptans are strongly retained in a small (20 mg) SPE cartridge containing p-hydroxymercurybenzoate. The cartridge can then be rinsed with relatively high volumes of polar (water/methanol mixtures) and non-polar (pentane or pentane/ether mixtures) rinsing solutions to remove nearly all volatile compounds lacking a thiol functionality. Retained analytes are further eluted with a small volume of an organic solvent containing 1,4-dithioerythritol. Some basic aspects of the strategy, such as the retention of p-hydroxymercurybenzoate in the sorbent and its stability versus different rinsing and eluting systems, have been studied in depth. Light sulfur compounds contained in water or wine, including mercaptans such as methanethiol or thioethers, such as diethyl sulfide, can be quantitatively extracted, although only mercaptans can be quantitatively recovered if a polar rinsing is applied. The strategy has been applied to the GC-MS quantitative determination of some trace polyfunctional mercaptans that are key aromas in wine, such as 2-methyl-3-furanthiol, 2-furfurylthiol, 4-mercapto-4-methyl-2-pentanone, 3-mercaptohexyl acetate or 3-mercaptohexanol. The developed method reaches detection limits in the ng/L range and has a satisfactory analytical behavior, being quite simple and fast. PMID:19813224

Mateo-Vivaracho, Laura; Cacho, Juan; Ferreira, Vicente

2009-11-01

196

Streptococcus pyogenes c-di-AMP Phosphodiesterase, GdpP, Influences SpeB Processing and Virulence  

PubMed Central

Small cyclic nucleotide derivatives are employed as second messengers by both prokaryotes and eukaryotes to regulate diverse cellular processes responding to various signals. In bacteria, c-di-AMP has been discovered most recently, and some Gram-positive pathogens including S. pyogenes use this cyclic nucleotide derivative as a second messenger instead of c-di-GMP, a well-studied important bacterial second messenger. GdpP, c-di-AMP phosphodiesterase, is responsible for degrading c-di-AMP inside cells, and the cellular role of GdpP in S. pyogenes has not been examined yet. To test the cellular role of GdpP, we created a strain with a nonpolar inframe deletion of the gdpP gene, and examined the properties of the strain including virulence. From this study, we demonstrated that GdpP influences the biogenesis of SpeB, the major secreted cysteine protease, at a post-translational level, susceptibility to the beta lactam antibiotic ampicillin, and is necessary for full virulence in a murine subcutaneous infection model.

Cho, Kyu Hong; Kang, Song Ok

2013-01-01

197

[Simultaneous determination of 5 kinds of alkaloids in Kechuanning tablets by SPE-UPLC under different UV-vis wavelength].  

PubMed

The paper is to establish a method for simultaneous determination of 5 kinds of alkaloids in ephedra and poppy which are in Kechuanning tablets. Solid-phase extraction (SPE) was adopted in pretreatment, and a UPLC method with 2 different wavelengths had been developed: 210 nm for the detection of morphine, codeine phosphate, ephedrine hydrochloride and pseudoephedrine hydrochloride, and 251 nm for papaverine hydrochloride. The column used was Acquity UPLC BEH C18 (100 mm x 2.1 mm ID, 1.7 microm) with linear gradient elution using acetonitrile and 0.1% phosphoric acid. The flow rate was 0.4 mL.min-1, and the column temperature was 30 degrees C. The linear response range was 0.375 0 - 12.50 microg.mL-1 for morphine, 0.064 32 - 2.144 microg.mL-1 for codeine phosphate, 0.030 06 - 1.002 microg.mL-1 for papaverine hydrochloride, 1.126 - 37.52 microg.mL-1 for ephedrine hydrochloride, 0.287 8 - 9.592 microg.mL-1 for pseudoephedrine hydrochloride (r = 0.999 7). The average recoveries of these compounds were 99.26%, 100.6%, 95.29%, 100.1% and 97.48%, respectively. This is a more reasonable and credible method of quality control for Kechuanning tablets. PMID:21800548

Liu, Yong-li; Li, Dong-mei; Feng, Li; Yuan, Hao

2011-05-01

198

Apoptosis in Gingival Overgrowth Tissues  

PubMed Central

Variations in the balance between cell proliferation and apoptosis could contribute to the etiology of gingival overgrowth. The aim of this study was to test the hypothesis that, in fibrotic gingival lesions, fibroblast proliferation is stimulated and apoptosis is decreased. Apoptotic index, caspase 3 expression, the proliferative index, FOXO1 expression, and histological inflammation were measured in situ. Analysis of data showed that apoptosis decreased in all forms of gingival overgrowth examined (p < 0.05), and inflammation caused a small but significant increase compared with non-inflamed tissues (p < 0.05). The greatest decrease of apoptosis occurred in the most fibrotic tissues. Cell proliferation was elevated in all forms of gingival overgrowth tested, independent of inflammation (p < 0.05). To identify potential mechanisms of transcriptional regulation of apoptosis, we assessed FOXO1 and caspase 3 expression levels and found them to correlate well with diminished apoptosis. Analysis of data suggests that increased fibroblast proliferation and a simultaneous decrease in apoptosis contribute to gingival overgrowth.

Kantarci, A.; Augustin, P.; Firatli, E.; Sheff, M.C.; Hasturk, H.; Graves, D.T.; Trackman, P.C.

2010-01-01

199

Mitochondrial control of nuclear apoptosis  

PubMed Central

Anucleate cells can be induced to undergo programmed cell death (PCD), indicating the existence of a cytoplasmic PCD pathway that functions independently from the nucleus. Cytoplasmic structures including mitochondria have been shown to participate in the control of apoptotic nuclear disintegration. Before cells exhibit common signs of nuclear apoptosis (chromatin condensation and endonuclease-mediated DNA fragmentation), they undergo a reduction of the mitochondrial transmembrane potential (delta psi m) that may be due to the opening of mitochondrial permeability transition (PT) pores. Here, we present direct evidence indicating that mitochondrial PT constitutes a critical early event of the apoptotic process. In a cell-free system combining purified mitochondria and nuclei, mitochondria undergoing PT suffice to induce chromatin condensation and DNA fragmentation. Induction of PT by pharmacological agents augments the apoptosis-inducing potential of mitochondria. In contrast, prevention of PT by pharmacological agents impedes nuclear apoptosis, both in vitro and in vivo. Mitochondria from hepatocytes or lymphoid cells undergoing apoptosis, but not those from normal cells, induce disintegration of isolated Hela nuclei. A specific ligand of the mitochondrial adenine nucleotide translocator (ANT), bongkreik acid, inhibits PT and reduces apoptosis induction by mitochondria in a cell-free system. Moreover, it inhibits the induction of apoptosis in intact cells. Several pieces of evidence suggest that the proto-oncogene product Bcl-2 inhibits apoptosis by preventing mitochondrial PT. First, to inhibit nuclear apoptosis, Bcl-2 must be localized in mitochondrial but not nuclear membranes. Second, transfection-enforced hyperexpression of Bcl-2 directly abolishes the induction of mitochondrial PT in response to a protonophore, a pro- oxidant, as well as to the ANT ligand atractyloside, correlating with its apoptosis-inhibitory effect. In conclusion, mitochondrial PT appears to be a critical step of the apoptotic cascade.

1996-01-01

200

Use of diffusion-ordered NMR spectroscopy and HPLC-UV-SPE-NMR to identify undeclared synthetic drugs in medicines illegally sold as phytotherapies.  

PubMed

The informal (and/or illegal) e-commerce of pharmaceutical formulations causes problems that governmental health agencies find hard to control, one of which concerns formulas sold as natural products. The purpose of this work was to explore the advantages and limitations of DOSY and HPLC-UV-SPE-NMR. These techniques were used to identify the components of a formula illegally marketed in Brazil as an herbal medicine possessing anti-inflammatory and analgesic properties. DOSY was able to detect the major components present at higher concentrations. Complete characterization was achieved using HPLC-UV-SPE-NMR, and 1D and 2D NMR analyses enabled the identification of known synthetic drugs. These were ranitidine and a mixture of orphenadrine citrate, piroxicam, and dexamethasone, which are co-formulated in a remedy called Rheumazim that is used to relieve severe pain, but it is prohibited in Brazil because of a lack of sufficient pharmacokinetic and pharmacodynamic information. PMID:23818305

Silva, Lorena M A; Filho, Elenilson G A; Thomasi, Sérgio S; Silva, Bianca F; Ferreira, Antonio G; Venâncio, Tiago

2013-07-02

201

Determination of organophosphorus insecticides in natural waters using SPE-disks and SPME followed by GC\\/FTD and GC\\/MS  

Microsoft Academic Search

Two methods for the analysis of ten organophosphorus insecticides in natural waters using solid phase extraction disks containing\\u000a C18 and SDB and solid phase microextraction fibers containing polyacrylate (PA) are developed. Bromophos ethyl, bromophos methyl,\\u000a dichlofenthion, ethion, fenamiphos, fenitrothion, fenthion, malathion, parathion ethyl and parathion methyl were determined\\u000a by GC\\/MS and GC\\/FTD. The SPE-disks require only 1000 mL of sample

D. Lambropoulou; T. Sakellarides; T. Albanis

2000-01-01

202

Determination and Characterization of Caffeine in Tea, Coffee and Soft Drinks by Solid Phase Extraction and High Performance Liquid Chromatography (SPE - HPLC)  

Microsoft Academic Search

Caffeine (1,3,5-trimethylxanthine), a mild addicting drug was isolated, purified and characterized from tea (black and green) and coffee. Isolation was done by liquid-liquid extraction using chloroform as an extracting solvent. Extraction was carried out in four steps such as leaching, dye removal, liquid extraction and recrystallization. Crude caffeine was purified by solid phase extraction (SPE) method. The solvent used for

Abdul Mumin; Kazi Farida Akhter; Zainal Abedin

203

Dissolution of hydrogen and the ratio of the dissolved hydrogen content to the produced hydrogen in electrolyzed water using SPE water electrolyzer  

Microsoft Academic Search

Concentration of dissolved hydrogen in electrolyzed water using a solid polymer electrolyte (SPE) water electrolyzer was investigated using a DH-meter. A ratio of the dissolved hydrogen content to an amount of hydrogen concentration calculated from charge passed during electrolysis was estimated. The ratio increased from 10 to 20% with a decrease in current density from 3.0 to 0.3 A dm?2.

Yoshinori Tanaka; Sakae Uchinashi; Yasuhiro Saihara; Kenji Kikuchi; Takuji Okaya; Zempachi Ogumi

2003-01-01

204

Analysis of anti-inflammatory, analgesic, stimulant and antidepressant drugs in purified water from wastewater treatment plants using SPE-LC tandem mass spectrometry  

Microsoft Academic Search

This work presents an effective sample preparation method for the evaluation of seven pharmaceutical compounds belonging to different therapeutic classes in purified water from wastewater treatment plants (WWTPs). The target compounds include caffeine (stimulant), nicotine (stimulant), atenolol (beta blocker), metamizole (anti-inflammatory and analgesic), fluoxetine (antidepressant), paraxanthine (stimulant) and clofibric acid (lipid regulator). Solid-phase extraction (SPE) and liquid chromatography-mass spectrometry (LC-MS)

Cristina Afonso-Olivares; Zoraida Sosa-Ferrera; José J. Santana-Rodríguez

2012-01-01

205

Glomerular cell apoptosis in human lupus nephritis  

Microsoft Academic Search

Disturbed apoptosis is proposed to be involved in the pathogenesis of systemic lupus erythematosus. However, the role of renal cell apoptosis in the pathogenesis and progression of human lupus nephritis is still controversial. We have investigated glomerular cell apoptosis and the clinicopathological relationship between apoptosis and immunoserological or histological findings in 22 patients with lupus nephritis using electron microscopy and

Hirofumi Makino; Hitoshi Sugiyama; Yasushi Yamasaki; Yohei Maeshima; Jun Wada; Naoki Kashihara

2003-01-01

206

Development of a bioassay-coupled HPLC-SPE-ttNMR platform for identification of ?-glucosidase inhibitors in apple peel (Malus ×domestica Borkh.).  

PubMed

This work describes an analytical platform based on a high-resolution ?-glucosidase inhibition assay in combination with hyphenation of high-performance liquid chromatography, solid-phase extraction, and tube-transfer nuclear magnetic resonance spectroscopy, i.e., HPLC-SPE-ttNMR/high-resolution ?-glucosidase assay. The platform enables fast screening for individual ?-glucosidase inhibitory analytes in complex matrices, followed by structural identification targeted these ?-glucosidase inhibitors, as demonstrated by a proof-of-concept study with extract of 'Pink Lady' apple peel. A scout-separation produced a high-resolution biochromatogram and a HPLC chromatogram, which were used for pinpointing HPLC peaks displaying ?-glucosidase inhibition. Active analytes were cumulatively trapped on SPE cartridges and the structures identified by (1)H NMR experiments obtained in the HPLC-SPE-ttNMR mode. (-)-Epicatechin (1), reynoutrin (3) and avicularin (4) were identified as active compounds. IC(50) of the active compounds were determined along with six structurally related compounds. Quercetin was the most potent inhibitor with an IC(50) of 8.1±0.4?M. The platform proved to be an efficient method for the identification of ?-glucosidase inhibitors. PMID:22953911

Schmidt, Jeppe S; Lauridsen, Michael B; Dragsted, Lars O; Nielsen, John; Staerk, Dan

2012-05-26

207

Crystal structure of the zymogen form of the group A Streptococcus virulence factor SpeB: an integrin-binding cysteine protease.  

PubMed

Pathogenic bacteria secrete protein toxins that weaken or disable their host, and thereby act as virulence factors. We have determined the crystal structure of streptococcal pyrogenic exotoxin B (SpeB), a cysteine protease that is a major virulence factor of the human pathogen Streptococcus pyogenes and participates in invasive disease episodes, including necrotizing fasciitis. The structure, determined for the 40-kDa precursor form of SpeB at 1.6-A resolution, reveals that the protein is a distant homologue of the papain superfamily that includes the mammalian cathepsins B, K, L, and S. Despite negligible sequence identity, the protease portion has the canonical papain fold, albeit with major loop insertions and deletions. The catalytic site differs from most other cysteine proteases in that it lacks the Asn residue of the Cys-His-Asn triad. The prosegment has a unique fold and inactivation mechanism that involves displacement of the catalytically essential His residue by a loop inserted into the active site. The structure also reveals the surface location of an integrin-binding Arg-Gly-Asp (RGD) motif that is a feature unique to SpeB among cysteine proteases and is linked to the pathogenesis of the most invasive strains of S. pyogenes. PMID:10681429

Kagawa, T F; Cooney, J C; Baker, H M; McSweeney, S; Liu, M; Gubba, S; Musser, J M; Baker, E N

2000-02-29

208

Platelet life span and apoptosis.  

PubMed

Like many nucleated mammalian cells, the life and death of the anucleate platelet is regulated by Bcl-2 family proteins. Platelets depend on Bcl-x(L) for survival. Bcl-x(L) maintains platelet viability by restraining the killer protein Bak. When Bak is unleashed, it triggers classical intrinsic apoptosis by causing mitochondrial damage. The latter leads to caspase activation and phosphatidylserine (PS) exposure. Platelet apoptosis can be blocked by caspase inhibitors, or by genetic deletion of Bak and its close relative Bax. Perturbations in the platelet apoptosis program lead to changes in platelet life span in vivo. Here, we describe methods to determine platelet life span, enumerate young platelets, and measure hallmarks of platelet apoptosis, such as PS exposure, caspase activation, and mitochondrial dysfunction. PMID:22130700

Josefsson, Emma C; White, Michael J; Dowling, Mark R; Kile, Benjamin T

2012-01-01

209

Keratocyte Apoptosis Associated with Keratoconus  

Microsoft Academic Search

Keratoconus is an ectatic corneal dystrophy associated with stromal thinning and disruption of Bowman's layer. The purpose of this study was to explore a possible association between keratocyte apoptosis and keratoconus. Keratocyte apoptosis was evaluated in corneas of patients with keratoconus, corneas of patients with stromal dystrophies, and normal donor corneas using the transferase-mediated dUTP-digoxigenin nick and labeling (TUNEL) assay.

WOO-JUNG KIM; YARON S RABINOWITZ; DAVID M MEISLER; STEVEN E WILSON

1999-01-01

210

Validation of SPE-HPLC determination of 1,4-benzodiazepines and metabolites in blood plasma, urine, and saliva.  

PubMed

A simple, sensitive, selective, and reproducible RP-HPLC method with DAD detection at 240 nm was developed for the determination of six 1,4-benzodiazepines: bromazepam (BRZ), clonazepam (CLZ), diazepam (DZP), flunitrazepam (FNZ), lorazepam (LRZ), alprazolam (APZ); and two metabolites: alpha-hydroxyalprazolam (HALZ) and alpha-hydroxytriazolam (HTZL) in human plasma, urine, and saliva, using colchicine as internal standard, after SPE using Nexus Varian cartridges. Separation was performed on a Kromasil C(8) (250 mm x 5 mm, 5 microm) analytical column with a gradient mobile phase containing methanol, ACN and 0.05 M ammonium acetate. Linearity was held within the range 0.3-20.0 ng/microL, with coefficients of determination (r(2)) better than 0.997. The within- and between-day assay RSD at 2, 4, 8 ng/microL ranged from 0.03 to 4.7% and 0.5 to 7.0%, respectively in standards, from 1.3 to 7.9% and 3.3 to 7.3%, respectively in plasma, from 2.1 to 6.0% and 2.1 to 7.8%, respectively in urine and at 0.5, 1.0, 2.0 ng/microL ranged from 2.22 to 5.8% and 2.2 to 8.1%, respectively, in saliva. The mean relative recoveries were 96.3-108.6, 96.0-108.2, 94.3-107.1, 97.0-107.0% in within-day assay and 96.8-107.7, 94.6-107.6, 93.2-105.8, 96.0-108.6 in between-day assay for standard, plasma, urine, and saliva, respectively. The LOD and LOQ were 0.02-0.47 and 0.07-1.57 ng/microL, respectively. PMID:19003810

Uddin, Mohammad Nasir; Samanidou, Victoria F; Papadoyannis, Ioannis N

2008-12-01

211

Modeling Mesospheric Odd Nitrogen during the October 1989 SPE with the Detailed Sodankylä Ion-Neutral Chemistry Model  

NASA Astrophysics Data System (ADS)

Precipitation of energetic particles affects the chemical balance of the middle atmosphere. It leads to enhanced production of some important minor neutral constituents, such as NO and OH, which might affect the ozone budget. Ion-neutral reactions play an important role in the production of minor neutrals. The Sodankylä Ion Chemistry (SIC) model was revised by combining relevant neutral chemistry with ion chemistry and is now used to investigate the effect of precipitation events on minor constituents, including NO and ozone. The new model covers altitudes from 50 to 100 km and can be used as steady-state or time-dependent model. At the moment SIC includes over 400 chemical reactions and models the behavior of 55 ion and 9 neutral species. The time-dependent model allows short-term variations of these species to be followed, so that their response to observed precipitation events or to sunrise/sunset effects can be studied in detail. We have modeled the behavior of odd nitrogen above Troms\\o (69.59N 19.23E) during the October 1989 solar proton event. Our results show how the intense particle ionization significantly increases the amount of atomic nitrogen and affects the N(4S)/N(2D) balance through ionic reactions. Also, ionic sources become important in NO production. As a consequence, NO is greatly enhanced between 60 and 100 km during days and between 50 and 100 km during nights. The increase of NO, up to three orders of magnitude, lasts beyond the end of the SPE. Ozone decrease due to reactions with enhanced odd nitrogen, odd hydrogen, and negative ions is seen below 85 km during nights, when sunlight is not present. Our modeling results for the sunset on the 23rd of October are compared with EISCAT incoherent scatter radar electron density measurements and a good agreement is found between 55 and 90 km.

Verronen, P.; Turunen, E.; Ulich, T.; Kyrölä, E.

2001-05-01

212

PPAR? and Apoptosis in Cancer  

PubMed Central

Peroxisome proliferator-activated receptors (PPARs) are ligand binding transcription factors which function in many physiological roles including lipid metabolism, cell growth, differentiation, and apoptosis. PPARs and their ligands have been shown to play a role in cancer. In particular, PPAR? ligands including endogenous prostaglandins and the synthetic thiazolidinediones (TZDs) can induce apoptosis of cancer cells with antitumor activity. Thus, PPAR? ligands have a potential in both chemoprevention and therapy of several types of cancer either as single agents or in combination with other antitumor agents. Accordingly, the involvement of PPAR? and its ligands in regulation of apoptosis of cancer cells have been extensively studied. Depending on cell types or ligands, induction of apoptosis in cancer cells by PPAR? ligands can be either PPAR?-dependent or -independent. Through increasing our understanding of the mechanisms of PPAR? ligand-induced apoptosis, we can develop better strategies which may include combining other antitumor agents for PPAR?-targeted cancer chemoprevention and therapy. This review will highlight recent research advances on PPAR? and apoptosis in cancer.

Elrod, Heath A.; Sun, Shi-Yong

2008-01-01

213

Organopalladium compound 7b targets mitochondrial thiols and induces caspase-dependent apoptosis in human myeloid leukemia cells  

PubMed Central

The advances in the treatment of chronic myeloid leukemia (CML) during the last years were also accompanied by the development of evading strategies by tumor cells, resulting in chemotherapy resistance in some patients. Patented organopalladium compounds derived from the reaction of N,N-dimethyl-1-phenethylamine (dmpa) with [1,2-ethanebis(diphenylphosphine)] (dppe) exhibited a potent antitumor activity in vivo and in vitro in melanoma cells. We showed here that the cyclopalladated derivative [Pd2(R(+))C2, N-dmpa)2(?-dppe)Cl2], named compound 7b, was highly effective to promote cell death in the K562 human leukemia cells and its mechanisms of action were investigated. It was shown that compound 7b was able to promote exclusively apoptotic cell death in K562 cells associated to cytochrome c release and caspase 3 activation. This cytotoxic effect was not observed in normal peripheral mononuclear blood cells. The compound 7b-induced intrinsic apoptotic pathway was triggered by the protein thiol oxidation that resulted in the dissipation of the mitochondrial transmembrane potential. The preventive effect of the dithiothreitol on the compound 7b-induced cell death and all downstream events associated to apoptosis confirmed that death signal was elicited by the thiol oxidation. These findings contribute to the elucidation of the palladacycle 7b-induced cell death mechanism and present this compound as a promising drug in the CML antitumor chemotherapy.

Moraes, V W R; Caires, A C F; Paredes-Gamero, E J; Rodrigues, T

2013-01-01

214

Inverse Relation between Disease Severity and Expression of the Streptococcal Cysteine Protease, SpeB, among Clonal M1T1 Isolates Recovered from Invasive Group A Streptococcal Infection Cases  

Microsoft Academic Search

The streptococcal cysteine protease (SpeB) is one of the major virulence factors produced by group A streptococci (GAS). In this study we investigated if differences exist in SpeB production by clonally related M1T1 clinical isolates derived from patients with invasive infections. Twenty-nine of these isolates were from nonsevere cases and 48 were from severe cases, including streptococcal toxic shock syndrome

RITA G. KANSAL; ALLISON MCGEER; DONALD E. LOW; ANNA NORRBY-TEGLUND; MALAK KOTB

2000-01-01

215

EndoS from Streptococcus pyogenes is hydrolyzed by the cysteine proteinase SpeB and requires glutamic acid 235 and tryptophans for IgG glycan-hydrolyzing activity  

Microsoft Academic Search

BACKGROUND: The endoglycosidase EndoS and the cysteine proteinase SpeB from the human pathogen Streptococcus pyogenes are functionally related in that they both hydrolyze IgG leading to impairment of opsonizing antibodies and thus enhance bacterial survival in human blood. In this study, we further investigated the relationship between EndoS and SpeB by examining their in vitro temporal production and stability and

Maria Allhorn; Arne Olsén; Mattias Collin

2008-01-01

216

Bacterial Porin Disrupts Mitochondrial Membrane Potential and Sensitizes Host Cells to Apoptosis  

PubMed Central

The bacterial PorB porin, an ATP-binding ?-barrel protein of pathogenic Neisseria gonorrhoeae, triggers host cell apoptosis by an unknown mechanism. PorB is targeted to and imported by host cell mitochondria, causing the breakdown of the mitochondrial membrane potential (??m). Here, we show that PorB induces the condensation of the mitochondrial matrix and the loss of cristae structures, sensitizing cells to the induction of apoptosis via signaling pathways activated by BH3-only proteins. PorB is imported into mitochondria through the general translocase TOM but, unexpectedly, is not recognized by the SAM sorting machinery, usually required for the assembly of ?-barrel proteins in the mitochondrial outer membrane. PorB integrates into the mitochondrial inner membrane, leading to the breakdown of ??m. The PorB channel is regulated by nucleotides and an isogenic PorB mutant defective in ATP-binding failed to induce ??m loss and apoptosis, demonstrating that dissipation of ??m is a requirement for cell death caused by neisserial infection.

Ross, Katharina; Rajalingam, Krishnaraj; Harsman, Anke; Hauf, Eva; Brinkmann, Volker; Gunther, Dirk; Herrmann, Ines; Hurwitz, Robert; Rassow, Joachim; Wagner, Richard; Rudel, Thomas

2009-01-01

217

Keratocyte apoptosis associated with keratoconus.  

PubMed

Keratoconus is an ectatic corneal dystrophy associated with stromal thinning and disruption of Bowman's layer. The purpose of this study was to explore a possible association between keratocyte apoptosis and keratoconus. Keratocyte apoptosis was evaluated in corneas of patients with keratoconus, corneas of patients with stromal dystrophies, and normal donor corneas using the transferase-mediated dUTP-digoxigenin nick and labeling (TUNEL) assay. Keratocyte apoptosis was also studied in keratoconus and normal corneas using transmission electron microscopy. TUNEL-stained keratocytes were detected in 60% of corneas with keratoconus, but only 35% of corneas with stromal dystrophies (P =0.03). The number of TUNEL-positive keratocytes detected in the keratoconus, stromal dystrophy, and normal corneas was 7+/-1 (mean+/-standard error, range 0-20), 2+/-0. 8 (range 0-9), and 0+/-0 (range 0-0) TUNEL-positive cells per section, respectively. The differences between the keratoconus and the stromal dystrophy (P =0.0097) or the normal cornea (P =0.01) groups were statistically significant. The difference between the stromal dystrophy and normal cornea groups was not statistically significant (P =0.45). The stromal dystrophy group was included to account for surgery-associated keratocyte apoptosis. No TUNEL-stained keratocytes were detected in normal corneas. Cell morphologic changes consistent with apoptosis were detected by transmission electron microscopy (TEM) in keratocytes of keratoconus corneas, but not in keratocytes in normal corneas. Chronic keratocyte apoptosis associated with ongoing epithelial injury may link risk factors associated with keratoconus such as chronic eye rubbing, contact lens wear, or atopic eye disease. Similarly, increases that have been detected in several different degradative enzymes in keratoconus corneas could be associated with chronic keratocyte apoptosis and less than perfect control of release of intracellular contents. PMID:10548467

Kim, W J; Rabinowitz, Y S; Meisler, D M; Wilson, S E

1999-11-01

218

Spontaneous apoptosis in human thymocytes.  

PubMed Central

Apoptosis seems to be involved in different stages of immune cell development. In particular, experimental evidence suggests that it is a major form of cell death in the thymus. The present analysis of human thymocytes reveals that a fraction of these cells, cultured in vitro, undergoes spontaneous apoptosis. This observation is based both on molecular (DNA fragmentation) and morphological (electron microscopic) investigations of the cells. The apoptotic thymocytes are CD3- or CD3lo, CD4lo, and CD8lo and do not express Bcl-2 protein. Furthermore, thymocytes die by apoptosis when exposed to pharmacological stimuli, such as tumor necrosis factor-alpha, dexamethasone, ATP, or Ca++ ionophore. Thus the apoptotic machinery in thymocytes can be triggered by an imbalance in growth factors in the in vitro culture media and can be modulated by various biochemical signals. The process of spontaneous apoptosis is independent of mRNA or protein synthesis, as actinomycin D and cycloheximide fail to inhibit this phenomenon. Furthermore, apoptosis seems to require active oxidative phosphorylation, as it is prevented by incubation of the cells with inhibitors of the respiratory chain. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 6 Figure 7 Figure 8

Tiso, M.; Gangemi, R.; Bargellesi Severi, A.; Pizzolitto, S.; Fabbi, M.; Risso, A.

1995-01-01

219

Bamboo charcoal as adsorbent for SPE coupled with monolithic column-HPLC for rapid determination of 16 polycyclic aromatic hydrocarbons in water samples.  

PubMed

The coupling of solid-phase extraction (SPE) using bamboo charcoal (BC) as an adsorbent with a monolithic column-high performance liquid chromatography (MC-HPLC) method was developed for the high-efficiency enrichment and rapid determination of 16 polycyclic aromatic hydrocarbons (PAHs) in water. Key influence factors, such as the type and the volume of the elution solvent, and the flow rate and the volume of the sample loading, were optimized to obtain a high SPE recovery and extraction efficiency. BC as an SPE adsorbent presented a high extraction efficiency due to its large specific surface area and high adsorption capacity; MC as an HPLC column accelerated the separation within 8 min because of its high porosity, fast mass transfer, and low-pressure resistance. The calibration curves for the PAHs extracted were linear in the range of 0.2-15 µg/L, with the correlation coefficients (r(2)) between 0.9970-0.9999. This method attained good precisions (relative standard deviation, RSD) from 3.5 to 10.9% for the standard PAHs I aqueous solutions at 5 µg/L; the method recoveries ranged in 52.6-121.6% for real spiked river water samples with 0.4 and 4 µg/L. The limits of detection (LODs, S/N = 3) of the method were determined from 11 and 87 ng/L. The developed method was demonstrated to be applicable for the rapid and sensitive determination of 16 PAHs in real environmental water samples. PMID:22586244

Ma, Jiping; Li, Mo; Li, Jinhua; Rui, Cuijie; Xin, Yanping; Xue, Qinzhao; Chen, Lingxin

2011-10-01

220

Comprehensive non-targeted analysis of contaminated groundwater of a former ammunition destruction site using 1H-NMR and HPLC-SPE-NMR/TOF-MS.  

PubMed

The aim of the present study was to explore the capabilities of the combination of 1H NMR (proton nuclear magnetic resonance) mixture analysis and HPLC-SPE-NMR/TOF-MS (high-performance liquid chromatography coupled to solid-phase extraction and nuclear magnetic resonance and time-of-flight mass spectrometry) for the characterization of xenobiotic contaminants in groundwater samples. As an example, solid-phase extracts of two groundwater samples taken from a former ammunition destruction site in Switzerland were investigated. 1H NMR spectra of postcolumn SPE enriched compounds, together with accurate mass measurements, allowed the structural elucidation of unknowns. This untargeted approach allowed us to identify expected residues of explosives such as 2,4,6-trinitrotoluene (2,4,6-TNT), Hexogen (RDX) and Octogen (HMX), degradation products of TNT (1,3,5-trinitrobenzene (1,3,5-TNB), 2-amino-4,6-dinitrotoluene (2-A-4,6-DNT), 3,5-dinitrophenol (3,5-DNP), 3,5-dinitroaniline (3,5-DNA), 2,6-dinitroanthranite, and 2-Hydroxy-4,6-dinitrobenzonitrile), benzoic acid, Bisphenol A (a known endocrine disruptor compound), and some toxicologically relevant additives for propelling charges: Centralite I (1,3-diethyl-1,3-diphenylurea), DPU (N,N-diphenylurethane), N,N-diphenylcarbamate (Acardite II), and N-methyl-N-phenylurethane. To our knowledge, this is the first report of the presence of these additives in environmental samples. Extraction recoveries for Centralite I and DPU have been determined. Contaminants identified by our techniques were quantified based on HPLC-UV (HPLC-ultraviolet detection) and 1H NMR mixture analysis. The concentrations of the contaminants ranged between 0.1 and 48 microg/L assuming 100% recovery for the SPE step. PMID:19806741

Godejohann, Markus; Heintz, Lea; Daolio, Cristina; Berset, Jean-Daniel; Muff, Daniel

2009-09-15

221

Mechanisms of Neuronal Apoptosis In Vivo.  

National Technical Information Service (NTIS)

Understanding the mechanisms of neuronal apoptosis in the central nervous system (CNS) has broad significance for military personnel and civilians. Neuronal apoptosis can occur after exposure to neurotoxins, radiation, and viruses and as a result of seizu...

L. J. Martin

2000-01-01

222

Preparation of guanidinium terminus-molecularly imprinted polymers for selective recognition and solid-phase extraction (SPE) of [arginine]-microcystins.  

PubMed

About 70 % of microcystin (MC) congeners reported in literature consist of L-arginine amino acid (R) with its guanidinium terminal extending out of the cyclic moiety of these MCs. Molecularly imprinted polymer (MIP) bearing guanidinium terminus cavities was successfully synthesised using L-arginine as a template. Non-imprinted polymer (NIP; without template) was also synthesised for control purposes. The surface area, total pore volume and average pore diameter of MIP and NIP were 267.13 m(2)/g, 0.63 cm(3)/g and 88.39 Å; 249.39 m(2)/g; 0.54 cm(3)/g and 87.14 Å, respectively. The polymers were investigated for selective recognition and extraction of [arginine]-MCs in water using solid-phase extraction/liquid chromatography-electrospray ionisation-mass spectrometry (SPE/LC-ESI-MS) method. Representative model standard solutions (0.5-10.0 ?g/L) of MC-LR and MC-LY were spiked in distilled water, recovered by SPE and quantified by LC-ESI-MS. In this study, Oasis Waters™ HLB cartridges served as positive control SPE sorbents. The MIP recognised MC-LR with high recoveries (70.8-91.4 %; r(2) = 0.9962) comparable to HLB cartridges (71.0-91.85 %; r(2) = 0.9993), whereas the NIP did not recognise or retain MC-LR. Also, neither MIP nor NIP recognised or retained MC-LY. Extracts of environmental toxic Microcystis aeruginosa were subjected to SPE procedure employing MIP, NIP and HLB cartridges. Microcystin-LR, -YR, -RR, -WR, -(H4)YR and (D-Asp(3), Dha(7))MC-RR were extracted by MIP and HLB cartridges only as confirmed by LC-ESI-MS. This study demonstrated that the prepared MIP have potential applications for the removal in water and LC-ESI-MS identifications of MCs consisting the guanidinium moiety, i.e.[arginine]-MCs, and in particular targeting commonly encountered toxic congeners, MC-LR, -YR and -RR. PMID:23430182

Mbukwa, Elbert A; Msagati, Titus A M; Mamba, Bhekie B

2013-02-21

223

Butyric Acid Induces Apoptosis in Inflamed Fibroblasts  

Microsoft Academic Search

Butyric acid, an extracellular metabolite from periodontopathic bacteria, induces apoptosis in murine and human T-and B-cells, whereas intact gingival fibroblasts isolated from healthy humans are resistant to butyric-acid-induced apoptosis. We examined the susceptibility of inflamed gingival fibroblasts isolated from adult persons with periodontitis to butyric-acid-induced apoptosis. Butyric acid significantly suppressed the viability of inflamed gingival fibroblasts and induced apoptosis in

T. Kurita-Ochiai; S. Seto; N. Suzuki; M. Yamamoto; K. Otsuka; K. Abe; K. Ochiai

2008-01-01

224

Inhibitor of apoptosis proteins in hematological malignancies  

Microsoft Academic Search

Apoptosis or programmed cell death is a key mechanism to control tissue homeostasis, for example, in the hematopoietic system. Thus, resistance to apoptosis can contribute to the development of leukemia or lymphoma. Inhibitors of apoptosis (IAP) proteins block cell death pathways at a central node by interfering with the activation of effector caspases. As increased expression levels of IAPs are

S Fulda

2009-01-01

225

Mitochondrial Dysfunction in Lyssavirus-Induced Apoptosis  

Microsoft Academic Search

Lyssaviruses are highly neurotropic viruses associated with neuronal apoptosis. Previous observations have indicated that the matrix proteins (M) of some lyssaviruses induce strong neuronal apoptosis. However, the molecular mechanism(s) involved in this phenomenon is still unknown. We show that for Mokola virus (MOK), a lyssavirus of low pathogenicity, the M (M-MOK) targets mitochondria, disrupts the mitochondrial morphology, and induces apoptosis.

Alireza Gholami; R. Kassis; E. Real; O. Delmas; S. Guadagnini; F. Larrous; D. Obach; Marie-Christine Prevost; Yves Jacob; H. Bourhy

2008-01-01

226

Comet assay and early apoptosis  

Microsoft Academic Search

The comet assay is a single cell gel electrophoresis test currently used as a qualitative and quantitative genotoxicity test. However, some of the results from this comet assay and current knowledge on apoptosis lead us to suspect the presence of some false positive results. The aim of this study was to ascertain if apoptotic cells can yield comet images that

P Choucroun; D Gillet; G Dorange; B Sawicki; J. D Dewitte

2001-01-01

227

Methylselenium and Prostate Cancer Apoptosis.  

National Technical Information Service (NTIS)

The purpose of this research is to gain a better understanding of the biochemical pathways and molecular targets for the selective induction of apoptosis signaling and execution of PCa cells by methyl selenium (Se)/selenol We hypothesized that methyl inhi...

J. Lu

2003-01-01

228

Pancreatic carcinogenesis: apoptosis and angiogenesis.  

PubMed

Apoptosis and angiogenesis are critical biologic processes that are altered during carcinogenesis. Both apoptosis and angiogenesis may play an important role in pancreatic carcinogenesis. Despite numerous advances in the diagnosis and treatment of pancreatic cancer, its prognosis remains dismal and a new therapeutic approach is much needed. Recent research has revealed that apoptosis and angiogenesis are closely interrelated. Several reports show that a tumor suppresser gene that is expressed in pancreatic carcinoma and related to malignant potential can induce apoptosis and also inhibit angiogenesis. At present, it is generally accepted that tumor growth in cancers, including pancreatic cancer, depends on angiogenesis. We have identified 2 new angiogenesis inhibitors from a conditioned medium of human pancreatic carcinoma cell line (BxPC-3): antiangiogenic antithrombin III (aaAT-III) and vitamin D binding protein-macrophage activating factor (DBP-maf). These molecules were able to regress tumors in severe combined immunodeficiency disease (SCID) mice, demonstrating potent inhibition of endothelial cell proliferation. Moreover, the angiogenesis inhibitors induced tumor dormancy in the animal model. These results suggest that antiangiogenic therapy using angiogenesis inhibitors may become a new strategy for treatment of pancreatic cancer in the near future. PMID:15084979

Onizuka, Shinya; Kawakami, Shunsuke; Taniguchi, Ken; Fujioka, Hikaru; Miyashita, Kosei

2004-04-01

229

ICE, neuronal apoptosis and neurodegeneration  

Microsoft Academic Search

Significant progress has recently occurred in the understanding of the molecular mechanisms mediating vertebrate programmed cell death, or apoptosis. New advances in this field have stemmed from the identification of ICE (caspase-1) as the founding member of the mammalian caspase cell death family. Apoptotic cell death plays an important role in neuronal cell death. Both in vitro and in vivo

Robert M Friedlander; Junying Yuan

1998-01-01

230

Viral Control of Mitochondrial Apoptosis  

Microsoft Academic Search

Throughout the process of pathogen–host co-evolution, viruses have developed a battery of distinct strategies to overcome biochemical and immunological defenses of the host. Thus, viruses have acquired the capacity to subvert host cell apoptosis, control inflammatory responses, and evade immune reactions. Since the elimination of infected cells via programmed cell death is one of the most ancestral defense mechanisms against

Lorenzo Galluzzi; Catherine Brenner; Eugenia Morselli; Zahia Touat; Guido Kroemer

2008-01-01

231

Mitochondrial Control of Nuclear Apoptosis  

Microsoft Academic Search

Summary Anucleate cells can be induced to undergo programmed cell death (PCD), indicating the exist- ence of a cytoplasmic PCD pathway that functions independently from the nucleus. Cytoplas- mic structures including mitochondria have been shown to participate in the control of apop- totic nuclear disintegration. Before cells exhibit common signs of nuclear apoptosis (chromatin condensation and endonuclease-mediated DNA fragmentation), they

Naoufal Zamzami; Santos A. Susin; Philippe Marchetti

1996-01-01

232

Requirements for proteolysis during apoptosis.  

PubMed Central

The key effector proteins of apoptosis are a family of cysteine proteases termed caspases. Following activation of caspases, biochemical events occur that lead to DNA degradation and the characteristic morphological changes associated with apoptosis. Here we show that cytoplasmic extracts activated in vitro by proteinase K were able to cleave the caspase substrate DEVD-7-amino-4-methylcoumarin, while neither proteinase K nor nonactivated extracts were able to do so alone. Caspase-like activity was inhibited by the specific caspase inhibitor DEVD-aldehyde and by the protease inhibitor iodoacetamide, but not by N-ethylmaleimide. When added to isolated nuclei, the activated extracts caused internucleosomal DNA degradation and morphological changes typical of apoptosis. As DNA cleavage and morphological changes could be inhibited by N-ethylmaleimide but not by iodoacetamide, we conclude that during apoptosis, caspase activation causes activation of another cytoplasmic enzyme that can be inhibited by N-ethylmaleimide. Activity of this enzyme is necessary for activation of endonucleases, DNA cleavage, and changes in nuclear morphology.

Vaux, D L; Wilhelm, S; Hacker, G

1997-01-01

233

GD3 ganglioside and apoptosis  

Microsoft Academic Search

Lipid and glycolipid mediators are important messengers of the adaptive responses to stress, including apoptosis. In mammalian cells, the intracellular accumulation of ganglioside GD3, an acidic glycosphingolipid, contributes to mitochondrial damage, a crucial event during the apoptopic program. GD3 is a minor ganglioside in most normal tissues. Its expression increases during development and in pathological conditions such as cancer and

Florence Malisan; Roberto Testi

2002-01-01

234

Activation of NF-?B following detachment delays apoptosis in intestinal epithelial cells  

PubMed Central

We reported earlier that IL-1?, an NF-?B-regulated cytokine, was made by intestinal epithelial cells during detachment-induced apoptosis (anoikis) and that IL-1 was antiapoptotic for detached cells. Since surviving anoikis is a prerequisite for cancer progression and metastases, we are further exploring the link between anoikis and cytokines. Here we determined that multiple genes are expressed following detachment including a number of NF-?B-regulated products and therefore aimed to determine whetherNF- ?B signalling plays any role in regulating apoptosis. Using Western blotting, we detected that I?B? becomes phosphorylated immediately following detachment and that levels of phospho-I?B? peaked within 20 min. Phosphorylation of I?B? was followed by Rel A (p65) nuclear translocation. Increased NF-?B activity following detachment was confirmed using the detection of NF-?B-promoted luciferase gene expression delivered by adenovirus infection. Infection of cells with adenovirus expressing a super-repressor I?B? protein and pharmacological inhibitors of NF-?B resulted in the failure to phosphorylate I?B?, a more rapid activation of caspases and earlier apoptosis. We also detected that I?B kinase ? (IKK?) and not IKK? became phosphorylated following detachment. Since IKK? is activated by NF-?B-inducing kinase (NIK), we overexpressed native NIK using an adenovirus vector that resulted in enhanced phospho-I?B? and nuclear p65 in detached cells compared to control detached cells but did not result in a significantly greater number of cells surviving to 24 h. We conclude that detachment directly activates NF-?B, which, in addition to launching an inflammatory cytokine wave, contributes to a delay in apoptosis in intestinal epithelial cells.

Yan, Sen Rong; Joseph, Robbie Randle; Rosen, Kirill; Reginato, Mauricio J; Jackson, Amanda; Allaire, Norman; Brugge, Joan S; Jobin, Christian; Stadnyk, Andrew W

2005-01-01

235

Radiation dose predictions for SPE events during solar cycle 23 from NASA's Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model  

NASA Astrophysics Data System (ADS)

NASA's High Charge and Energy Transport (HZETRN) code is a deterministic model for rapid and accurate calculations of the particle radiation fields in the space environment. HZETRN is used to calculate dosimetric quantities on the International Space Station (ISS) and assess astronaut risk to space radiations, including realistic spacecraft and human geometry for final exposure evaluation. HZETRN is used as an engineering design tool for materials research for radiation shielding protection. Moreover, it is used to calculate HZE propagation through the Earth and Martian atmospheres, and to evaluate radiation exposures for epidemiological studies. A new research project has begun that will use HZETRN as the transport engine for the development of a nowcast prediction of air-crew radiation exposure for both background galactic cosmic ray (GCR) exposure and radiation exposure during solar particle events (SPE) that may accompany solar storms. The new air-crew radiation exposure model is called the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model, which utilizes real-time observations from ground-based, atmospheric, and satellite measurements. In this paper, we compute the global distribution of atmospheric radiation dose for several SPE events during solar cycle 23, with particular emphasis on the high-latitude and polar region. We also characterize the suppression of the geomagnetic cutoff rigidity during these storm periods and their subsequent influence on atmospheric radiation exposure.

Mertens, Christopher; Blattnig, Steve; Slaba, Tony; Kress, Brian; Wiltberger, Michael; Solomon, Stan

236

Systematic investigation of orthogonal SPE sample preparation for the LC-MS/MS bioanalysis of a monoclonal antibody after pellet digestion.  

PubMed

Background: Increasing assay sensitivity is critical for promoting the application of LC-MS/MS quantitative bioanalysis of therapeutic proteins. A sample processing method that can selectively remove the abundant background peptides in the serum tryptic digests and retain the target peptides can greatly improve the assay sensitivity. Results: Mixed-mode strong-cation exchange SPE was systematically investigated as an orthogonal sample separation technique to reversed-phase UHPLC for the analysis of a test monoclonal antibody, BMS-986012, in monkey serum after pellet digestion. Strong cation exchange SPE efficiently removed most of the background peptides and reduced the matrix effect and background level in the monitored mass transition channels. As a result, improved sensitivity was observed for the surrogate peptides VVSV and SLIY. Conclusion: This orthogonal approach provides a simple and easy-to-develop sample preparation method that can selectively remove most background peptides and extract the target peptides, therefore, improving the LC-MS/MS assay sensitivity. PMID:24066623

Yuan, Long; Aubry, Anne-Françoise; Arnold, Mark E; Ji, Qin C

2013-10-01

237

Inactivation of the group A Streptococcus regulator srv results in chromosome wide reduction of transcript levels, and changes in extracellular levels of Sic and SpeB  

PubMed Central

Group A Streptococcus is characterized by the ability to cause a diverse number of human infections including pharyngitis, necrotizing fasciitis, toxic shock syndrome, and acute rheumatic fever, yet the regulation of streptococcal genes involved in disease processes and survival in the host is not completely understood. Genome scale analysis has revealed a complex regulatory network including 13 two-component regulatory systems and more than 100 additional putative regulators, the majority of which remain uncharacterized. Among these is the streptococcal regulator of virulence, Srv, the first Group A Streptococcus member of the Crp/Fnr family of transcriptional regulators. Previous work demonstrated that the loss of srv resulted in a significant decrease in Group A Streptococcus virulence. To begin to define the gene products influenced by Srv, we combined microarray and two-dimensional gel electrophoresis analysis. Loss of srv results in a chromosome wide reduction of gene transcription and changes in the production of the extracellular virulence factors Sic (streptococcal inhibitor of complement) and SpeB (cysteine proteinase). Sic levels are reduced in the srv mutant, whereas the extracellular concentration and activity of SpeB is increased. These data link Srv to the increasingly complex GAS regulatory network.

Reid, Sean D.; Chaussee, Michael S.; Doern, Christopher D.; Chaussee, Michelle A.; Montgomery, Alison G.; Sturdevant, Daniel E.; Musser, James M.

2009-01-01

238

Molecularly imprinted SPE coupled with HPLC for the selective separation and enrichment of alkyl imidazolium ionic liquids in environmental water samples.  

PubMed

A novel 1-butyl-3-methylimidazolium chloride ionic liquid surface imprinted solid-phase sorbent was synthesized. The as-prepared material was characterized by SEM, Brunauer-Emmett-Teller surface area analysis and Fourier Transform IR measurements. Then its adsorption properties for alkyl imidazolium ionic liquids, including adsorption capacities, adsorption kinetics, and properties of selective separation and enrichment were studied in detail. It was shown that the ionic liquid surface imprinted polymer exhibited high selective recognition characteristics for the imidazolium chloride ionic liquids with short alkyl chains (Cn mimCl, n = 2, 4, 6, 8) and the adsorption equilibrium was achieved within 25 min. Various parameters were optimized for the 1-butyl-3-methylimidazolium chloride ionic liquid surface imprinted polymer SPE column, such as flow rate, eluent solvent, selectivity, and reusability of the column. Then, the SPE column coupled with HPLC was used for the determination of alkyl imidazolium ionic liquids. Experimental results showed that the existence of their structural analogs and common concomitants in environmental matrices did not affect the enrichment of 1-butyl-3-methyl imidazolium chloride ionic liquid. The average recoveries of 1-butyl-3-methylimidazolium chloride ionic liquid in spiked water samples were in the range of 92.0-102.0% with the RSD lower than 5.8%. PMID:23970465

Xia, Gao; Jing, Fan; Guifen, Zhu; Xiaolong, Wang; Jianji, Wang

2013-08-23

239

Diabetes and renal tubular cell apoptosis  

PubMed Central

Apoptosis contributes to the development of diabetic nephropathy, but the mechanism by which high glucose induces apoptosis is not fully understood. Apoptosis of tubular epithelial cells is a major feature of diabetic kidney disease, and hyperglycemia triggers the generation of free radicals and oxidant stress in tubular cells. Hyperglycemia and high glucose in vitro also lead to apoptosis, a form of programmed cell death. High glucose similar to those seen with hyperglycemia in people with diabetes mellitus, lead to accelerated apoptosis, a form of programmed cell death characterized by cell shrinkage, chromatin condensation and DNA fragmentation, in variety of cell types, including renal proximal tubular epithelial cells.

Habib, Samy L

2013-01-01

240

Saponin B, a novel cytostatic compound purified from Anemone taipaiensis, induces apoptosis in a human glioblastoma cell line.  

PubMed

Glioblastoma multiforme (GBM) is one of the most common malignant brain tumors. Saponin B, a novel compound isolated from the medicinal plant, Anemone taipaiensis, has been found to have a strong time- and dose-dependent cytostatic effect on human glioma cells and to suppress the growth of U87MG GBM cells. In this study, we investigated whether saponin B induces the apoptosis of glioblastoma cells and examined the underlying mechanism(s) of action of saponin B. Saponin B signi?cantly suppressed U87MG cell proliferation. Flow cytometric analysis of DNA in the U87MG cells con?rmed that saponin B blocked the cell cycle at the S phase. Furthermore, treatment of the U87MG cells with saponin B induced chromatin condensation and led to the formation of apoptotic bodies, as observed under a ?uorescence microscope, and Annexin V/PI assay further suggested that phosphatidylserine (PS) externalization was apparent at higher drug concentrations. Treatment with saponin B activated the receptor-mediated pathway of apoptosis, as western blot analysis revealed the activation of Fas-l. Saponin B increased the Bax and caspase-3 ratio and decreased the protein expression of Bcl-2. The results from the present study demonstrate that the novel compound, saponin B, effectively induces the apoptosis of GBM cells and inhibits glioma cell growth and survival. Therefore, saponin B may be a potential candidate for the development of novel cancer therapeutics with antitumor activity against gliomas. PMID:24048272

Wang, Yuangang; Tang, Haifeng; Zhang, Yun; Li, Juan; Li, Bo; Gao, Zhenhui; Wang, Xiaoyang; Cheng, Guang; Fei, Zhou

2013-09-18

241

DDM1 and ROS1 have a role in UV-B induced- and oxidative DNA damage in A. thaliana.  

PubMed

Absorption of UV-B by DNA induces the formation of covalent bonds between adjacent pyrimidines. In maize and arabidopsis, plants deficient in chromatin remodeling show increased DNA damage compared to WT plants after a UV-B treatment. However, the role of enzymes that participate in DNA methylation in DNA repair after UV-B damage was not previously investigated. In this work, we analyzed how chromatin remodeling activities that have an effect on DNA methylation affects the repair of UV-B damaged DNA using plants deficient in the expression of DDM1 and ROS1. First, we analyzed their regulation by UV-B radiation in arabidopsis plants. Then, we demonstrated that ddm1 mutants accumulated more DNA damage after UV-B exposure compared to Col0 plants. Surprisingly, ros1 mutants show less CPDs and 6-4PPs than WT plants after the treatment under light conditions, while the repair under dark conditions is impaired. Transcripts for two photolyases are highly induced by UV-B in ros1 mutants, suggesting that the lower accumulation of photoproducts by UV-B is due to increased photorepair in these mutants. Finally, we demonstrate that oxidative DNA damage does not occur after UV-B exposure in arabidopsis plants; however, ros1 plants accumulate high levels of oxoproducts, while ddm1 mutants have less oxoproducts than Col0 plants, suggesting that both ROS1 and DDM1 have a role in the repair of oxidative DNA damage. Together, our data provide evidence that both DDM1 and ROS1, directly or indirectly, participate in UV-B induced- and oxidative DNA damage repair. PMID:24155752

Qüesta, Julia I; Fina, Julieta P; Casati, Paula

2013-10-21

242

DDM1 and ROS1 have a role in UV-B induced- and oxidative DNA damage in A. thaliana  

PubMed Central

Absorption of UV-B by DNA induces the formation of covalent bonds between adjacent pyrimidines. In maize and arabidopsis, plants deficient in chromatin remodeling show increased DNA damage compared to WT plants after a UV-B treatment. However, the role of enzymes that participate in DNA methylation in DNA repair after UV-B damage was not previously investigated. In this work, we analyzed how chromatin remodeling activities that have an effect on DNA methylation affects the repair of UV-B damaged DNA using plants deficient in the expression of DDM1 and ROS1. First, we analyzed their regulation by UV-B radiation in arabidopsis plants. Then, we demonstrated that ddm1 mutants accumulated more DNA damage after UV-B exposure compared to Col0 plants. Surprisingly, ros1 mutants show less CPDs and 6-4PPs than WT plants after the treatment under light conditions, while the repair under dark conditions is impaired. Transcripts for two photolyases are highly induced by UV-B in ros1 mutants, suggesting that the lower accumulation of photoproducts by UV-B is due to increased photorepair in these mutants. Finally, we demonstrate that oxidative DNA damage does not occur after UV-B exposure in arabidopsis plants; however, ros1 plants accumulate high levels of oxoproducts, while ddm1 mutants have less oxoproducts than Col0 plants, suggesting that both ROS1 and DDM1 have a role in the repair of oxidative DNA damage. Together, our data provide evidence that both DDM1 and ROS1, directly or indirectly, participate in UV-B induced- and oxidative DNA damage repair.

Questa, Julia I.; Fina, Julieta P.; Casati, Paula

2013-01-01

243

Tissue transglutaminase: apoptosis versus autoimmunity  

Microsoft Academic Search

Autoimmune diseases are characterized by multiple autoantibodies and\\/or autoreactive T cells that recognize a large number of antigens. Many of these antigens undergo extensive post-translational modifications during apoptosis and act as substrates for the pro-apoptotic cystein proteases. Here, Mauro Piacentini and Vittorio Colizzi discuss the effects on autoimmunity produced by post-translational modifications of proteins catalysed by the pro-apoptotic enzyme tissue

Mauro Piacentini; Vittorio Colizzi

1999-01-01

244

APOPTOSIS: Life and Death Decisions  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Screening small molecules for their ability to perturb a cellular pathway, a strategy called forward chemical genetics, can yield unexpected information about other pathway components. This is well illustrated by new work (Jiang et al.), as Nicholson and Thornberry discuss in their Perspective. Discovery of a small-molecule activator of apoptosis implicated a tumor suppressor protein and an oncoprotein in the regulation of the mitochondrial cell death pathway.

Donald W. Nicholson (Merck Frosst Centre for Therapeutic Research, Merck Research Laboratories;); Nancy A. Thornberry (Merck Research Laboratories;)

2003-01-10

245

Autoimmunity, Apoptosis Defects and Retroviruses  

Microsoft Academic Search

\\u000a Autoimmune disease in both mice and humans is associated with increased expression of endogenous retroviruses in the thymus\\u000a and T cells, and loss of self-tolerance by T cells. The basic genetic defect underlying autoimmune disease has been identified\\u000a as a mutation of the Fas apoptosis antigen in MRL-lpr\\/lpr mice or a mutation of the Fas ligand in C3H-gld\\/gld mice. In

J. D. Mountz; J. Cheng; X. Su; J. Wu; T. Zhou

246

Role of nitric oxide in UV-B-induced activation of PAL and stimulation of flavonoid biosynthesis in Ginkgo biloba callus  

Microsoft Academic Search

The role of nitric oxide (NO) in UV-B-induced secondary metabolite accumulation in Ginkgo biloba callus was investigated. Overall, UV-B irradiation induced multiple biological responses in callus of G. biloba, including increased both NO production and nitric oxide synthase (NOS) activity, and subsequent activation of phenylalanine\\u000a ammonium lyase (PAL) and synthesis of flavonoids. Application of NO via the donor sodium nitroprusside (SNP) enhanced

Gangping Hao; Xihua Du; Faxing Zhao; Renjiu Shi; Jianmei Wang

2009-01-01

247

GT1b-induced neurotoxicity is mediated by the Akt\\/GSK-3\\/tau signaling pathway but not caspase-3 in mesencephalic dopaminergic neurons  

Microsoft Academic Search

BACKGROUND: Gangliosides, sialic acid-containing glycosphingolipids exist in mammalian cell membranes particularly neuronal membranes. The trisialoganglioside (GT1b) is one of the major brain gangliosides and acts as an endogenous regulator in the brain. We previously showed GT1b induces mesencephalic dopaminergic (DA) neuronal death, both in vivo and in vitro. We further investigate the underlying mechanisms of GT1b neurotoxicity. RESULTS: Consistent with

Eun S Chung; Eugene Bok; Sunghyang Sohn; Young D Lee; Hyung H Baik; Byung K Jin

2010-01-01

248

Butyric acid induces apoptosis in inflamed fibroblasts.  

PubMed

Butyric acid, an extracellular metabolite from periodontopathic bacteria, induces apoptosis in murine and human T- and B-cells, whereas intact gingival fibroblasts isolated from healthy humans are resistant to butyric-acid-induced apoptosis. We examined the susceptibility of inflamed gingival fibroblasts isolated from adult persons with periodontitis to butyric-acid-induced apoptosis. Butyric acid significantly suppressed the viability of inflamed gingival fibroblasts and induced apoptosis in a dose-dependent manner. The incubation of inflamed gingival fibroblasts with butyric acid induced DNA fragmentation and apoptotic changes such as chromatin condensation, hypodiploid nuclei, and mitochondrial injury. Furthermore, butyric-acid-induced apoptosis in inflamed gingival fibroblasts was reduced by caspase-3/7, -6, -8, and -9 inhibitors. Thus, inflamed gingival fibroblasts from adult persons with periodontitis appear to be highly susceptible to mitochondria- and caspase-dependent apoptosis induced by butyric acid, compared with healthy gingival fibroblasts. PMID:18096893

Kurita-Ochiai, T; Seto, S; Suzuki, N; Yamamoto, M; Otsuka, K; Abe, K; Ochiai, K

2008-01-01

249

MicroSPE-nanoLC-ESI-MS/MS using 10-µm-i.d. silica-based monolithic columns for proteomics  

SciTech Connect

Silica-based monolithic narrow bore capillary columns (25 cm ? 10 ?m i.d.) with an integrated ESI emitter has been developed to provide high quality and robust microSPE-nanoLC-ESI-MS analyses. The integrated ESI emitter adds no dead volume to the LC separation, allowing stable electrospray performance to be obtained at flow rates of ?10 nL/min. In an initial application we identified 5510 unique peptides covering 1443 distinct Shewanella oneidensis proteins from a 300 ng tryptic digest sample in a single 4-h LC-MS/MS analysis using a linear ion trap MS (LTQ). We found the use of an integrated monolithic ESI emitter provided enhanced resistance to clogging and good run-to-run reproducibility, with an average variation of {approx}25% for triplicate analyses.

Luo, Quanzhou; Page, Jason S.; Tang, Keqi; Smith, Richard D.

2007-01-15

250

Factors affecting UV-B-induced changes in Arabidopsis thaliana L. gene expression: the role of development, protective pigments and the chloroplast signal.  

PubMed

Gene expression is known to change in response to UV-B radiation. In this paper, we have investigated three factors in Arabidopsis leaves that are likely to influence these changes: development, protective pigments and the 'chloroplast signal'. During late leaf development the major change in pigment composition, after exposure to UV-B radiation, is an increase in UV-absorbing pigments. Chl and Chl a/b ratio do not change substantially. Similarly Chl fluorescence is not altered. In contrast, RNA transcripts for photosynthetic proteins are reduced more in older leaves than in young leaves. To determine the role of flavonoids in UV-B protection, plants of Arabidopsis mutant tt-5, which have reduced flavonoids and sinapic esters, were exposed to UV-B and RNA transcript levels determined. The tt-mutants were more sensitive to UV-B radiation than wild-type. To examine the role of the chloroplast signal in regulating UV-B-induced changes in gene expression, Arabidopsis gun mutants (genome uncoupled) have been used. The results show that UV-B-induced down-regulation still takes place in gun mutants and strongly suggests that the chloroplast signal is not required. Overall, this study clearly demonstrates that UV-B-induced changes in gene expression are influenced by both developmental and cellular factors but not chloroplastic factors. PMID:9729900

Jordan, B R; James, P E; A-H-Mackerness, S

1998-07-01

251

Identification of small molecules that induce apoptosis in a Myc-dependent manner and inhibit Myc-driven transformation  

PubMed Central

The Myc transcription factor plays a central role in the regulation of cell cycle progression, apoptosis, angiogenesis, and cellular transformation. Myc is a potent oncoprotein that is deregulated in a wide variety of human tumors and is therefore an attractive target for novel cancer therapies. Using a cellular screening approach, we have identified low-molecular-weight compounds, Myc pathway response agents (MYRAs), that induce apoptosis in a c-Myc-dependent manner and inhibit Myc-driven cellular transformation. MYRA-A inhibits Myc transactivation and interferes with the DNA-binding activity of Myc family proteins but has no effect on the E-box-binding protein USF. In contrast, MYRA-B induces Myc-dependent apoptosis without affecting Myc transactivation or Myc/Max DNA binding. Our data show that cellular screening assays can be a powerful strategy for the identification of candidate substances that modulate the Myc pathway. These compounds can be useful tools for studying Myc function and may also be of therapeutic potential as leads for drug development.

Mo, Hao; Henriksson, Marie

2006-01-01

252

GCR and SPE organ doses in deep space with different shielding: Monte Carlo simulations based on the FLUKA code coupled to anthropomorphic phantoms  

NASA Astrophysics Data System (ADS)

Astronauts’ exposure to space radiation is of high concern for long-term missions, especially for those in deep space such as possible travels to Mars. In these cases shielding optimization is a crucial issue, and simulations based on radiation transport codes and anthropomorphic model phantoms can be of great help. In this work the FLUKA Monte Carlo code was coupled with two anthropomorphic phantoms (a mathematical model and a “voxel” model) to calculate organ-averaged dose, dose equivalent and “biological dose” in the various tissues and organs following exposure to the August 1972 Solar Particle Event and to Galactic Cosmic Rays under different shielding conditions. The “biological dose” was characterized by the average number of induced “Complex Lesions” (CLs) per cell in a given organ or tissue, where CLs are clustered DNA breaks which can play an important role in chromosome aberration induction. Separate calculation of the contributions from secondary hadrons in particular neutrons with respect to primary particles allowed us to quantify the role played by nuclear interactions occurring in the shield and in the human body. Specifically for GCR, the contributions from the different components of the incident primary spectra were calculated separately as well. As expected, the SPE doses showed a dramatic decrease with increasing Al shielding. Furthermore, for SPEs internal organs received much lower doses with respect to skin, and nuclear interactions were found to be of minor importance. A 10 g/cm2 Al storm shelter turned out to be sufficient to respect the NCRP limits for 30-days LEO missions in case of a SPE similar to the August 1972 event. In contrast with SPEs, GCR absorbed doses remained roughly constant with increasing Al shielding. The organ-averaged dose equivalent and biological dose showed a (slight) decrease starting from a shield thickness of 2 g/cm2, probably due the lower LET of projectile fragments.

Ballarini, F.; Battistoni, G.; Cerutti, F.; Fassò, A.; Ferrari, A.; Gadioli, E.; Garzelli, M. V.; Mairani, A.; Ottolenghi, A.; Paretzke, H. G.; Parini, V.; Pelliccioni, M.; Pinsky, L.; Sala, P. R.; Scannicchio, D.; Trovati, S.; Zankl, M.

253

On-flow pulsed field gradient heteronuclear correlation spectrometry in off-line LC-SPE-NMR analysis of chemicals related to the chemical weapons convention.  

PubMed

Hyphenation of liquid chromatography with nuclear magnetic resonance spectroscopy (LC-NMR) is a useful technique in the analysis of complex samples. However, application of on-flow 1H NMR spectrometry during the LC-NMR analysis usually suffers from high intensity of eluent resonances. The poor dynamic range can be improved either with use of deuterated eluents or with various signal suppression schemes. Deuterated eluents are expensive, and peak-selective signal suppression schemes are often unsatisfactory when detection of chemicals at low concentration is needed. If the analytes have a common heteronucleus, on-flow pulsed field gradient heteronuclear correlation spectrometry can offer several benefits. The analytes can be monitored selectively, while the intense nondeuterated eluent and impurity background can be effectively eliminated. In our study, on-flow one-dimensional (1D) 1H-31P heteronuclear single quantum coherence (HSQC) spectrometry was utilized in the analysis of characteristic organophosphorus degradation products of nerve agents sarin and soman during chromatographic separation. These chemicals were not detectable by UV, so their retention times were monitored using on-flow 1D 1H-31P HSQC. This enabled application of LC-NMR combined with solid-phase extraction (LC-SPE-NMR) in analysis of these organophosphorus chemicals in an alkaline decontamination solution. The analytes were extracted from the SPE cartridges with deuterated eluent, and the off-line NMR analysis was performed using a mass-sensitive microcoil probe head. The used on-flow 1D 1H-31P HSQC approach offered a high dynamic range and good detection limit (ca. 10 microg/55 nmol) with a high sampling frequency (1 point per 2 s) in the acquired pseudo-two-dimensional spectrum. No significant impurity background was present in the off-line NMR samples, and identification of the extracted analytes was straightforward. PMID:19128090

Koskela, Harri; Ervasti, Mia; Björk, Heikki; Vanninen, Paula

2009-02-01

254

Bioenergetic aspects of apoptosis, necrosis and mitoptosis  

Microsoft Academic Search

In this review I summarize interrelations between bioenergetic processes and such programmed death phenomena as cell suicide\\u000a (apoptosis and necrosis) and mitochondrial suicide (mitoptosis). The following conclusions are made. (I) ATP and rather often\\u000a mitochondrial hyperpolarization (i.e. an increase in membrane potential, ??) are required for certain steps of apoptosis and necrosis. (II) Apoptosis, even if\\u000a it is accompanied by

V. P. Skulachev

2006-01-01

255

Apoptosis in Lung Injury and Disease  

Microsoft Academic Search

Pulmonary cell death may contribute significantly to acute and chronic lung injuries caused by various adverse environmental\\u000a agents. Pulmonary cells may die by necrosis, apoptosis, and other forms of regulated cell death. Apoptosis exerts a homeostatic\\u000a function in lung defense and development, through the removal of dysfunctional cells and by regulating cellular proliferation.\\u000a Lung cell apoptosis can occur as a

Stefan W. Ryter; Hong Pyo Kim; Augustine M. K. Choi

256

Apoptosis in Liver Injury and Liver Diseases  

Microsoft Academic Search

The liver is a multifunctional organ that has important roles such as metabolism, synthesis, and detoxification. Enhanced\\u000a hepatocyte apoptosis and impaired liver regeneration are the most common liver disorders in acute liver failure. Hepatocyte\\u000a apoptosis also emerges as a fundamental component of chronic liver diseases. Liver tissue fibrosis is triggered by hepatocyte\\u000a apoptosis, and the excess fibrosis causes liver disease

Yosuke Osawa; Ekihiro Seki; David A. Brenner

257

Local Anesthetics Induce Human Renal Cell Apoptosis  

Microsoft Academic Search

Renal cell apoptosis contributes significantly to the pathogenesis of acute renal failure. Local anesthetics induce apoptosis in neuronal and lymphocytic cell lines. We examined the effects of chronic (48 h) local anesthetic treatment (lidocaine, bupivacaine and tetracaine) on human proximal tubular (HK-2) cells. Apoptosis induction was assessed by detecting poly(ADP)-ribose polymerase fragmentation, caspase activation, terminal deoxynucleotidyl transferase biotin-dUTP nick end

H. Thomas Lee; Hua Xu; Cory D. Siegel; Igor E. Krichevsky

2003-01-01

258

Apoptosis and aging: increased resistance to apoptosis enhances the aging process  

Microsoft Academic Search

Apoptosis is a vital component in the evolutionarily conserved host defense system. Apoptosis is the guardian of tissue integrity\\u000a by removing unfit and injured cells without evoking inflammation. However, apoptosis seems to be a double-edged sword since\\u000a during low-level chronic stress, such as in aging, increased resistance to apoptosis can lead to the survival of functionally\\u000a deficient, post-mitotic cells with

Antero Salminen; Johanna Ojala; Kai Kaarniranta

2011-01-01

259

Apoptosis in cancer: from pathogenesis to treatment  

PubMed Central

Apoptosis is an ordered and orchestrated cellular process that occurs in physiological and pathological conditions. It is also one of the most studied topics among cell biologists. An understanding of the underlying mechanism of apoptosis is important as it plays a pivotal role in the pathogenesis of many diseases. In some, the problem is due to too much apoptosis, such as in the case of degenerative diseases while in others, too little apoptosis is the culprit. Cancer is one of the scenarios where too little apoptosis occurs, resulting in malignant cells that will not die. The mechanism of apoptosis is complex and involves many pathways. Defects can occur at any point along these pathways, leading to malignant transformation of the affected cells, tumour metastasis and resistance to anticancer drugs. Despite being the cause of problem, apoptosis plays an important role in the treatment of cancer as it is a popular target of many treatment strategies. The abundance of literature suggests that targeting apoptosis in cancer is feasible. However, many troubling questions arise with the use of new drugs or treatment strategies that are designed to enhance apoptosis and critical tests must be passed before they can be used safely in human subjects.

2011-01-01

260

Targeting apoptosis pathways in childhood malignancies.  

PubMed

Evasion of apoptosis (programmed cell death) is a characteristic feature of human cancers including childhood malignancies. Since cytotoxic therapies such as chemotherapy or radiotherapy trigger apoptosis as a primary mechanism of action, resistance to apoptosis can also lead to treatment resistance. Studies on apoptosis pathways in childhood malignancies yielded a series of key molecules that can now be exploited as molecular targets for the development of targeted therapies. This strategy is anticipated to open novel perspectives for more effective treatment options for children with cancer. PMID:21036468

Fulda, Simone

2010-10-30

261

The cellular decision between apoptosis and autophagy.  

PubMed

Apoptosis and autophagy are important molecular processes that maintain organismal and cellular homeostasis, respectively. While apoptosis fulfills its role through dismantling damaged or unwanted cells, autophagy maintains cellular homeostasis through recycling selective intracellular organelles and molecules. Yet in some conditions, autophagy can lead to cell death. Apoptosis and autophagy can be stimulated by the same stresses. Emerging evidence indicates an interplay between the core proteins in both pathways, which underlies the molecular mechanism of the crosstalk between apoptosis and autophagy. This review summarizes recent literature on molecules that regulate both the apoptotic and autophagic processes. PMID:23114086

Fan, Yong-Jun; Zong, Wei-Xing

2012-10-10

262

SPE Combined with HPLC-APCI-MS Analysis of Pesticides in Water: Method Performance and Application in a Reconnaissance Survey of Residues in Drinking Water in Greater Cairo (Egypt)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The portability, ease of use, and potential to enhance analyte stability makes solid-phase extraction (SPE) an attractive technique for extracting water samples collected for pesticide residue analysis prior to their shipment to analytical laboratories. The technique is especially valuable when samp...

263

APOPTOSIS: Death by Crowd Control  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Cells often die by way of a controlled suicide called apoptosis. The proteins most responsible for the deed are caspases, specific proteases that are carefully regulated in the cell so that they only become activated when absolutely necessary. In his Perspective, Hengartner discusss results reported by Yang et al. in the same issue on how some of the central caspases responsible for cell death, such as CED-3, are activated by oligomerization, a process that is regulated by the anti-death protein CED-9, a member of the large Bcl-2 family.

Michael Hengartner (Cold Spring Harbor Laboratory;)

1998-08-28

264

HIV-1 Induced Bystander Apoptosis  

PubMed Central

Apoptosis of uninfected bystander cells is a key element of HIV pathogenesis and believed to be the driving force behind the selective depletion of CD4+ T cells leading to immunodeficiency. While several viral proteins have been implicated in this process the complex interaction between Env glycoprotein expressed on the surface of infected cells and the receptor and co-receptor expressing bystander cells has been proposed as a major mechanism. HIV-1 utilizes CD4 as the primary receptor for entry into cells; however, it is the viral co-receptor usage that greatly influences CD4 decline and progression to AIDS. This phenomenon is relatively simple for X4 viruses, which arise later during the course of the disease, are considered to be highly fusogenic, and cause a rapid CD4+ T cell decline. However, in contrast, R5 viruses in general have a greater transmissibility, are encountered early during the disease and have a lesser pathogenic potential than the former. The above generalization gets complicated in numerous situations where R5 viruses persist throughout the disease and are capable of causing a rigorous CD4+ T cell decline. This review will discuss the multiple factors that are reported to influence HIV induced bystander apoptosis and pathogenesis including Env glycoprotein phenotype, virus tropism, disease stage, co-receptor expression on CD4+ T cells, immune activation and therapies targeting the viral envelope.

Garg, Himanshu; Mohl, Jonathon; Joshi, Anjali

2012-01-01

265

Cell Cycle and Apoptosis1  

PubMed Central

Abstract In multicellular organisms, cell proliferation and death must be regulated to maintain tissue homeostasis. Many observations suggest that this regulation may be achieved, in part, by coupling the process of cell cycle progression and programmed cell death by using and controlling a shared set of factors. An argument in favor of a link between the cell cycle and apoptosis arises from the accumulated evidence that manipulation of the cell cycle may either prevent or induce an apoptotic response. This linkage has been recognized for tumor suppressor genes such as p53 and RB, the dominant oncogene, c-Myc, and several cyclin-dependent kinases (Cdks) and their regulators. These proteins that function in proliferative pathways may also act to sensitize cells to apoptosis. Indeed, unregulated cell proliferation can result in pathologic conditions including neoplasias if it is not countered by the appropriate cell death. Translating the knowledge gained by studying the connection between cell death and cell proliferation may aid in identifying novel therapies to circumvent disease progression or improve clinical outcome.

Pucci, Bruna; Kasten, Margaret; Giordano, Antonio

2000-01-01

266

CELL BIOLOGY: Apoptosis--the Calcium Connection  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Calcium ions are crucial to many cellular processes including apoptosis. In their Perspective, Demaurex and Distelhorst explain new work that shows how calcium ions flowing between the endoplasmic reticulum (ER) and mitochondria regulate programmed cell death, highlighting the ER as a new gateway to apoptosis (Scorrano et al.).

Nicolas Demaurex (University of Geneva Medical Center;Department of Physiology); Clark Distelhorst (Case Western Reserve University Medical School;Department of Medicine)

2003-04-04

267

Apoptosis and glutathione: beyond an antioxidant  

Microsoft Academic Search

Apoptosis is a conserved homeostatic process critical for organ and tissue morphogenesis, development, and senescence. This form of programmed cell death also participates in the etiology of several human diseases including cancer, neurodegenerative, and autoimmune disorders. Although the signaling pathways leading to the progression of apoptosis have been extensively characterized, recent studies highlight the regulatory role of changes in the

R Franco; J A Cidlowski

2009-01-01

268

Apoptosis: controlled demolition at the cellular level  

Microsoft Academic Search

Apoptosis is characterized by a series of dramatic perturbations to the cellular architecture that contribute not only to cell death, but also prepare cells for removal by phagocytes and prevent unwanted immune responses. Much of what happens during the demolition phase of apoptosis is orchestrated by members of the caspase family of cysteine proteases. These proteases target several hundred proteins

Rebecca C. Taylor; Sean P. Cullen; Seamus J. Martin

2008-01-01

269

Emerging roles of caspase-3 in apoptosis  

Microsoft Academic Search

Caspases are crucial mediators of programmed cell death (apoptosis). Among them, caspase-3 is a frequently activated death protease, catalyzing the specific cleavage of many key cellular proteins. However, the specific requirements of this (or any other) caspase in apoptosis have remained largely unknown until now. Pathways to caspase-3 activation have been identified that are either dependent on or independent of

Alan G Porter; Reiner U Jänicke

1999-01-01

270

Excitotoxins in Neuronal Apoptosis and Necrosis  

Microsoft Academic Search

Neuronal loss is common to many neurodegenerative diseases. Although necrosis is a common histopathologic feature observed in neuropathologic conditions, evidence is increasing that apoptosis can significantly contribute to neuronal demise. The prevalence of either type of cell death, apoptosis or necrosis, and the relevance for the progression of disease is still unclear. The debate on the occurrence and prevalence of

Pierluigi Nicotera; Stuart A. Lipton

1999-01-01

271

THE ROLE OF APOPTOSIS IN NEUROTOXICOLOGY.  

EPA Science Inventory

The role of apoptosis in neurodegeneration in developing animals and in adults has become increasingly apparent in the past ten years. Normal apoptosis occurs in the CNS from the embryonic stage through senescence, with different cells in each region of the nervous system having ...

272

Proteases in Fas-mediated apoptosis.  

PubMed

Involvement of a unique family of cysteine proteases in the multistep apoptotic process has been documented. Cloning of several mammalian genes identifies some components of this cellular response. However, it is currently unclear which protease plays a role as a signal and/or effector of apoptosis. We summarize contributions to the data concerning proteases in Fas-mediated apoptosis. PMID:9015753

Zhivotovsky, B; Burgess, D H; Schlegel, J; Pörn, M I; Vanags, D; Orrenius, S

1997-01-01

273

[Herpesviruses survival strategies--latency and apoptosis].  

PubMed

Apoptosis is a process of programmed cell death in response to various stimuli, including virus infection. Herpesviruses have evolved the ability to interfere with apoptosis by its inhibition or activation in host cells. They can interfere with the extrinsic and intrinsic pathways of apoptosis. A special feature of herpesviruses is establishing a latent infection, during which expression of virus genes is strongly restricted and production of infectious virus particles is not observed. HSV-1 establishes latency in neurons, CMV in bone marrow progenitor cells and monocytes, EBV and HHV-8 in B cells. Studies show that latent infections also depend on prevention of the death of the infected cells. Control of apoptosis machinery by viruses may be critical for their reproduction and provision of the adequate yield of progeny virions. The present article summarizes the current knowledge about the latent viral infection and mechanisms of apoptosis modulation by selected viruses from the Herpesviridae family. PMID:23619227

Miszczak, Dariusz; S?o?ska, Anna; Golke, Anna; Cymerys, Joanna

2013-04-15

274

[The apoptosis-supressing activity of clamydia].  

PubMed

The paper covers data from literature, concerning the influence of bacteria upon apoptosis program of host's cells. The mechanisms of apoptosis induction and suppression, developed by bacteria and directed towards the maintenance of conditions favorable to the infection, are quite varied. These mechanisms are realized via complex interaction between biologically active bacterial molecules and particular targets of signal paths which lead to apoptosis. In intracellular parasitism the apoptosis-suppressing activity of bacteria may be considered to be one of the mechanisms of pathogenic organism's persistence which provide favorable conditions for the development of chronic infections. Infection caused by C. pneumoniae in human fibroblasts has been experimentally demonstrated to protect the cells from spontaneous and induced apoptosis. PMID:15715153

Zigangirova, N A; Martynova, V R; Kolkova, N I; Fedina, E D; Gintsburg, A L

2005-01-01

275

Induction of apoptosis by Shiga toxins  

PubMed Central

Shiga toxins comprise a family of structurally and functionally related protein toxins expressed by Shigella dysenteriae serotype 1 and multiple serotypes of Escherichia coli. While the capacity of Shiga toxins to inhibit protein synthesis by catalytic inactivation of eukaryotic ribosomes has been well described, it is also apparent that Shiga toxins trigger apoptosis in many cell types. This review presents evidence that Shiga toxins induce apoptosis of epithelial, endothelial, leukocytic, lymphoid and neuronal cells. Apoptotic signaling pathways activated by the toxins are reviewed with an emphasis on signaling mechanisms that are shared among different cell types. Data suggesting that Shiga toxins induce apoptosis through the endoplasmic reticulum stress response and clinical evidence demonstrating apoptosis in humans infected with Shiga toxin-producing bacteria are briefly discussed. The potential for use of Shiga toxins to induce apoptosis in cancer cells is briefly reviewed.

Tesh, Vernon L

2010-01-01

276

Baculoviruses and apoptosis: a diversity of genes and responses.  

PubMed

Apoptosis is used by metazoan organisms to dispose of damaged or unnecessary cells during development, tissue homeostasis, and disease. One of the situations where apoptosis is important is in defense against microbial pathogens, especially viruses. The demonstration that apoptosis could be stimulated by baculovirus infection was one of the first examples of apoptosis associated with virus infection, and this system remains one of the most valuable for studying how apoptosis can be a defense against viruses. In addition, studying how baculoviruses regulate apoptosis has led to many important findings in the field of apoptosis research, such as the discovery of P35, a caspase inhibitor that is widely used in studies of apoptosis, and IAP (inhibitor of apoptosis) proteins, which have homologs in cellular genomes that play important roles in regulating apoptosis and cytokinesis. This review highlights the range of apoptotic responses observed between different baculoviruses and different lepidopteran insects, and the diverse baculovirus genes that have evolved to regulate apoptosis. PMID:17979666

Clem, Rollie J

2007-10-01

277

Models and Monte Carlo simulations of GCR and SPE organ doses with different shielding, based on the FLUKA code coupled with anthropomorphic phantoms  

NASA Astrophysics Data System (ADS)

Astronauts' exposure to space radiation is of major concern for long-term missions, especially for those in deep space such as a possible mission to Mars. Shielding optimization is therefore a crucial issue, and simulations based on radiation transport codes coupled with anthropomorphic model phantoms can be of great help. In this work, carried out with the FLUKA MC code and two anthropomorphic phantoms (a mathematical model and a "voxel" model), distributions of physical (i.e. absorbed), equivalent and "biological" dose in the various tissues and organs were calculated in different shielding conditions for solar minimum and solar maximum GCR spectra, as well as for the August 1972 Solar Particle Event. The biological dose was modeled as the average number of "Complex Lesions" (CL) per cell in a given organ. CLs are clustered DNA breaks previously calculated with "event-by-event" track structure simulations and integrated in the condensed-history FLUKA code. This approach is peculiar in that it is an example of a mechanistically-based quantification of the ionizing radiation action in biological targets; indeed CLs have been shown to play a fundamental role in chromosome aberration induction. The contributions of primary particles and secondary hadrons were calculated separately, thus allowing quantification of the role of nuclear reactions in the shield and in the human body. As expected, the doses calculated for the 1972 SPE decrease dramatically with increasing the Al shielding; nuclear reactions were found to be of minor importance, although their role is higher for internal organs and large shielding. An Al shield thickness of 10 g/cm2 appears sufficient to respect the 30-day deterministic limits recommended by NCRP for missions in Low Earth Orbit. In contrast with the results obtained for SPE, GCR doses to internal organs are not significantly lower than skin doses. However, the relative contribution of secondary hadrons was found to be more important for internal organs due to nuclear interactions in the human body. Both for skin and for internal organs, the physical dose was found to be essentially independent of the shield thickness. The equivalent and biological doses to skin show a significant decrease starting from 5 g/cm2, whereas internal organs show more complex trends characterized by minima and maxima mainly dependent on the organ type. Polyethylene shielding resulted to be more effective with respect to Aluminum.

Ballarini, F.; Fluka-Phantoms Team

278

Chemopreventive Effects of Sarcophine-diol on Ultraviolet B-induced Skin Tumor Development in SKH-1 Hairless Mice  

PubMed Central

Sarcophine-diol (SD), one of the structural modifications of sarcophine, has shown chemopreventive effects on 12-dimethylbenz(a)anthracene-initiated and 12-O-tetradecanoylphorbol-13-acetate-promoted skin tumor development in female CD-1 mice. The objective of this study was to determine the chemopreventive effects of SD on UVB-induced skin tumor development in hairless SKH-1 mice, a model more relevant to human skin cancer, and to determine the possible mechanisms of action. Carcinogenesis was initiated and promoted by UVB radiation. Female hairless SKH-1 mice were divided into two groups having 27 mice in each group: control and SD treatment. The control group was topically treated with 100 ?L acetone and SD treatment group was topically treated with SD (30 ?g/100 ?L in acetone) 1 hour before each UVB radiation for 32 weeks. Tumor counts were recorded on a weekly basis for 30 weeks. Effects of SD on the expression of caspases were investigated to elucidate the possible mechanism of action. The proteins from epidermal homogenates of experimental mice were used for SDS-PAGE and Western blotting using specific antibodies against caspase-3, caspase-8 and caspase-9 respectively. TUNEL assay was used for determining DNA fragmented apoptotic cells in situ. Results showed that at the end of experiment, tumor multiplicity in control and SD treatment groups was 25.8 and 16.5 tumors per mouse respectively. Furthermore, Topical treatment of SD induced DNA fragmented apoptotic cells by upgrading the expressions of cleaved caspase-3 and caspase-8. This study clearly suggested that SD could be an effective chemopreventive agent for UVB-induced skin cancer by inducing caspase dependent apoptosis.

Zhang, Xiaoying; Bommareddy, Ajay; Chen, Wei; Hildreth, Michael B.; Kaushik, Radhey S.; Zeman, David; Khalifa, Sherief; Fahmy, Hesham; Dwivedi, Chandradhar

2009-01-01

279

Chemopreventive Effects of Sarcotriol on Ultraviolet B-induced Skin Tumor Development in SKH-1 Hairless Mice  

PubMed Central

Sarcotriol (ST) has been shown to be chemopreventive on 7,12-dimethyl-benz(a)anthracene (DMBA) initiated and 12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted skin tumor development in CD-1 mice in recent studies from our laboratory. The objective of this study was to determine the chemopreventive effects of ST on ultraviolet B (UVB)-induced skin tumor development in female SKH-1 hairless mice, an experimental model relevant to human skin cancer development, and its possible mechanisms of action. Female SKH-1 mice were divided into two groups: Control and ST treated. Control was topically treated with 100 ?L acetone and ST treated group administered with 30 ?g ST in 100 ?L acetone one hour before UVB exposure. For UVB-induced tumorigenesis, carcinogenesis was initiated and promoted by UVB (180 mJ/cm2). Group weights and tumor counts were taken once every week. After 30 weeks, mice were sacrificed and dorsal skin samples were collected. The proteins from the skin sample were further used for SDS-PAGE and Western blotting using specific antibodies against caspase-3, caspase-8, caspase-9 and p53. Tumor multiplicity was found 19.6, 5.2 in the control and ST treated groups respectively. Caspase-3, -8, -9 and p53 were significantly (P < 0.05) upregulated in ST treated group compared to Control group. Together, this study for the first time identifies the chemopreventive effects of ST in UVB-induced carcinogenesis possibly by inducing apoptosis and upregulating p53.

Kundoor, Vipra; Zhang, Xiaoying; Bommareddy, Ajay; Khalifa, Sherief; Fahmy, Hesham; Dwivedi, Chandradhar

2007-01-01

280

Hyperthermia induces apoptosis in thymocytes  

SciTech Connect

Mild hyperthermia (43{degree}C for 1 h) induces extensive double-stranded DNA fragmentation and, at a later time, cell death in murine thymocytes. The cleavage of DNA into oligonucleosome-sized fragments resembles that observed in examples of apoptosis including radiation-induced death of thymocytes. Following hyperthermia, incubation at 37{degree}C is necessary to detect DNA fragmentation, although protein and RNA synthesis do not seem to be required. Two protein synthesis inhibitors, cycloheximide and emetine, and two RNA synthesis inhibitors, actinomycin D and 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole, do not inhibit DNA fragmentation or cell death in heated thymocytes at concentrations which significantly block these effects in irradiated thymocytes. We have used this difference in sensitivity to show that the DNA fragmentation induced in thymocytes which are irradiated and then heated seems to be caused only by the heating and not by the irradiation.

Sellins, K.S.; Cohen, J.J. (Univ. of Colorado School of Medicine, Denver (USA))

1991-04-01

281

Proneurotrophins, Seizures, and Neuronal Apoptosis  

PubMed Central

Neurons respond to numerous factors in their environment that influence their survival and function during development and in the mature brain. Among these factors, the neurotrophins have been shown to support neuronal survival and function, acting primarily through the Trk family of receptor tyrosine kinases. However, recent studies have established that the uncleaved neurotrophin precursors, the proneurotrophins, can be secreted and induce apoptosis via the p75 neurotrophin receptor, suggesting that the balance of secreted mature and proneurotrophins has a critical impact on neuronal survival or death. Epileptic seizures elicit increases in both proneurotrophin secretion and p75NTR expression, shifting the balance of these factors toward signaling cell death. This review will discuss the evidence that this ligand-receptor system plays an important role in neuronal loss following seizures.

Friedman, Wilma J.

2010-01-01

282

APOPTOSIS: Death of a Monopoly?  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Hunot and Flavell discuss recent findings in Nature by Joza et al. that point to the existence of a new sort of cell death. Cell death is required during the development of an organism to remove portions of the body that will not be needed; this cell death usually requires destructive enzymes called caspases to perform the final demolition of the cell. But cavitation, an early developmental process in the mouse embryo that requires cell death, has now been suggested to occur through a caspase-independent pathway that instead uses a mitochondrial protein called AIF (apoptosis-inducing factor).

Stéphane Hunot (Yale University School of Medicine;Section of Immunobiology and the Howard Hughes Medical Institute); Richard A. Flavell (Yale University School of Medicine;Section of Immunobiology and the Howard Hughes Medical Institute)

2001-05-04

283

Apaf-1- and Caspase-8-independent apoptosis.  

PubMed

Two major apoptosis pathways, the mitochondrial and death receptor pathways, are well recognized. Here we established cell lines from the fetal thymus of Apaf-1-, Caspase-9-, or Bax/Bak-deficient mice. These cell lines were resistant to apoptosis induced by DNA-damaging agents, RNA or protein synthesis inhibitors, or stress in the endoplasmic reticulum. However, they underwent efficient apoptosis when treated with kinase inhibitors such as staurosporine and H-89, indicating that these inhibitors induce a caspase-dependent apoptosis that is different from the mitochondrial pathway. CrmA, a Caspase-8 inhibitor, did not prevent staurosporine-induced apoptosis of fetal thymic cell lines, suggesting that the death receptor pathway was also not involved in this process. The staurosporine-induced cell death was inhibited by okadaic acid, a serine/threonine phosphatase inhibitor, suggesting that dephosphorylation of a proapoptotic molecule triggered the death process, or that phosphorylation of an antiapoptotic molecule could block the process. Cells of various types (fetal thymocytes, bone marrows, thymocytes, and splenocytes), but not embryonic fibroblasts, were sensitive to the noncanonical staurosporine-induced apoptosis, suggesting that the noncanonical apoptosis pathway is tissue specific. PMID:23197294

Imao, T; Nagata, S

2012-11-30

284

Control of Apoptosis by Human Cytomegalovirus  

Microsoft Academic Search

Caspase-dependent apoptosis has an important role in controlling viruses, and as a result, viruses often encode proteins that\\u000a target this pathway. Caspase-dependent apoptosis can be activated from within the infected cell as an intrinsic response to\\u000a replication-associated stresses or through death-inducing signals produced extrinsically by immune cells. Cytomegaloviruses\\u000a (CMVs) encode a mitochondria-localized inhibitor of apoptosis, vMIA, and a viral inhibitor

A. L. McCormick

285

[Physiological and pathological roles of apoptosis].  

PubMed

An understanding of the cellular events leading to apoptosis is important for the design of new chemotherapeutic agents directed against the types of leukemias and lymphomas that are resistant to currently used chemotherapeutic protocols. Malignant cell proliferation and accumulation depend on an imbalance between the rate of cell production and the rate of cell death. Apoptosis has been demonstrated to be involved not only in the regulation of normal tissues but also in the development and control of tumour cells. The relationship between oncogenes, apoptosis and growth factors is very important in determining prognosis when analysing the potential benefits of different treatment regimens. PMID:12092216

Vasiliu, O M; Goga, L M; Cotrutz, C E; Cotrutz, C; Ionescu, C R

286

Antioxidants prevent ethanol-associated apoptosis in fetal rhombencephalic neurons  

Microsoft Academic Search

It is well known that ethanol damages the developing nervous system by augmenting apoptosis. Previously, this laboratory reported that ethanol augments apoptosis in fetal rhombencephalic neurons, and that the increased apoptosis is associated with reduced activity of the phosphatidylinositol 3-kinase pathway and downstream expression of pro-survival genes. Other laboratories have shown that another mechanism by which ethanol induces apoptosis in

Angeline M. Antonio; Mary J. Druse

2008-01-01

287

Apoptosis in the repair process of experimental proliferative glomerulonephritis  

Microsoft Academic Search

Apoptosis in the repair process of experimental proliferative glomerulonephritis. The recovery from the proliferative glomerulonephritis (GN) with reduction of hypercellularity is known in various experimental and human GN. To elucidate the participation of apoptosis in GN, we studied the experimental Thy-1.1 GN for six weeks. Apoptosis was recognized by both light and electron microscopy, and the biochemical expression of apoptosis

Akira Shimizu; Hiroshi Kitamura; Yukinari Masuda; Masamichi Ishizaki; Yuichi Sugisaki; Nobuaki Yamanaka

1995-01-01

288

Use of SPE-GC/EIMS for residue analysis in wine elaborated from musts spiked with formulations of chlorpyriphos-methyl, methiocarb, dicofol, and cyproconazol.  

PubMed

The likely presence in wine of residues of the active ingredient and its degradation products, besides the byproducts and excipients of the commercial formulation, has been investigated for four pesticides. Formulations containing chlorpyriphos-methyl, methiocarb, dicofol, and cyproconazol were added to must, which was subjected to a usual vinification. The wines elaborated from must spiked with the formulation of chlorpyriphos-methyl contained two pyridinol compounds in addition to excipients such as alkylbenzenes, naphthalene, and methylnaphthalenes. Methiocarb was hydrolyzed to yield the corresponding phenol, and various unidentified compounds related to cyproconazol were observed in wine. The residues of the dicofol-containing formulation resulted to be dechlorination products; impurities from its commercial formulation were also detected in must and wine extracts. White wines contained higher amounts of residues than red wines. The residues were detected after an SPE followed by GC/EIMS in the scan mode. The concentrations of the active ingredients were determined by a matrix-matched calibration to avoid quantitative errors arising from the matrix. PMID:17444223

Jiménez, Juan José; Bernal, José Luis; del Nozal, María J; Toribio, Laura; Bernal, José

2007-03-01

289

Analytical method for the determination of atrazine and its dealkylated chlorotriazine metabolites in water using SPE sample preparation and GC-MSD analysis.  

PubMed

A method is reported for the determination of atrazine and its dealkylated chlorotriazine metabolites in ground, surface, and deionized water. Water samples are adjusted to pH 3-4 prior to loading onto two SPE cartridges in series: C-18 and C-18/cation exchange mixed-mode polymeric phases. The analytes are eluted from each of the two cartridges separately, and the pooled and concentrated fraction is analyzed using gas chromatography-mass selective detection in the selected ion monitoring mode. The lower limit of method validation is 0.10 micrograms/L (ppb) for 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), 2-amino-4-chloro-6-(isopropylamino)-s-triazine (G-30033, deethylatrazine), 2-amino-4-chloro-6-(ethylamino)-s-triazine (G-28279, deisopropylatrazine), and 2,4-diamino-6-chloro-s-triazine (G-28273, didealkyatrazine). The overall mean procedural recoveries (and standard deviations) are 96 (6.9), 96 (5.5), 95 (6.8), and 100% (10%) for atrazine, G-30033, G-28279, and G-28273, respectively (n = 49). The method validation study was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelines 40 CFR 160. The reported procedure accounts for residues of G-28273 in water. PMID:14640566

Huang, Sung-Ben; Stanton, Jeffrey S; Lin, Yi; Yokley, Robert A

2003-12-01

290

Optimization and validation of a simple and fast method for the determination of fungicides in must and wine samples by SPE and GC/MS.  

PubMed

A rapid, simple, and low-cost method based on SPE was optimized and validated for simultaneous determination of eight fungicides belonging to different chemical classes in must and wine. The method involves extraction of 10 mL of must or wine samples with a C18 cartridge using 5 mL of dichloromethane as the elution solvent. Separation and final determination of the fungicides (vinclozolin, dichlofluanid, penconazol, captan, quinoxyfen, fluquinconazol, boscalid, and pyraclostrobin) was performed by GC coupled to single quadrupole MS. Recoveries at 10, 50, and 100 microg/L were between 71 and 106% in both matrixes for the fungicides evaluated. The calculated LOQ ranged from 1.5 to 3.4 microg/L in must and 1.1 to 3.8 microg/L in wine. Matrix effects observed for wine and must samples were overcome by using matrix-matched calibration. The developed method was linear at concentrations within the tested interval, with coefficients of determination higher than 0.999. The expanded uncertainties at 10 microg/L were <20% for all analytes. Intralaboratory precision in terms of the Horwitz ratio of the fungicides evaluated was below 0.5, suggesting the ruggedness of the method. The proposed method was applied to determine fungicide residues in must samples obtained from red grapes treated with two new commercial formulations, as well as in their corresponding final wines. PMID:23175987

Lagunas-Allué, Laura; Sanz-Asensio, Jesús; Martínez-Soria, Maria-Teresa

291

Bioaccumulation assessment of the sunscreen agent 2-ethylhexyl 4-(N,N-dimethylamino)benzoate in human semen by automated online SPE-LC-MS/MS.  

PubMed

The proven endocrine disruption nature of the sunscreen ingredient 2-ethylhexyl 4-(N,N-dimethylamino)benzoate (EDP) calls for research to understand its distribution and bioaccumulation in the human body. A sensitive analytical method to determine EDP and its metabolites in human semen based on online SPE-LC-MS/MS is described. The method has been fully validated and a standard addition calibration has been used for quantification to correct the observed matrix effects. The on-column detection limits of the analytes are between 0.2 and 0.6 ng, depending on the analyte and the sample. The repeatability of the method, expressed as relative standard deviation, was in the range 4.6-9.4%. The method was satisfactorily applied to semen samples from male volunteers who were subjected to single and repeated whole-body applications of an EDP-containing sunscreen product. EDP metabolites were found at different concentrations in semen samples from the repeated application study, thus showing evidences of bioaccumulation in humans. PMID:21637928

León-González, Zacarías; Ferreiro-Vera, Carlos; Priego-Capote, Feliciano; Luque de Castro, María Dolores

2011-06-03

292

Occurrence of polar organic contaminants in the dissolved water phase of the Danube River and its major tributaries using SPE-LC-MS(2) analysis.  

PubMed

Polar water-soluble organic contaminants were analysed in the dissolved liquid water phase of river water samples from the Danube River and its major tributaries (within the Joint Danube Survey 2). Analyses were performed by solid-phase extraction (SPE) followed by triple-quadrupole liquid chromatography mass spectrometry (LC-MS(2)). In total, 34 different polar organic compounds were screened. Focus was given on pharmaceutical compounds (such as ibuprofen, diclofenac, sulfamethoxazole, carbamazepine), pesticides and their degradation products (e.g. bentazone, 2,4-D, mecoprop, atrazine, terbutylazine, desethylterbutylazine), perfluorinated acids (PFOS; PFOA), and endocrine disrupting compounds (nonylphenol, NPE(1)C, bisphenol A, estrone). The most relevant polar compounds identified in the Danube River basin in terms of frequency of detection, persistency, and concentration levels were 1H-benzotriazole (median concentration 185 ng/L), caffeine (87 ng/L), tolyltriazole (73 ng/L), nonylphenoxy acetic acid (49 ng/L), carbamazepine (33 ng/L), 4-nitrophenol (29 ng/L), 2,4-dinitrophenol (19 ng/L), PFOA (17 ng/L), sulfamethoxazole (16 ng/L), desethylatrazine (11 ng/L), and 2,4-D (10 ng/L). The highest contamination levels were found in the area around Budapest and in the tributary rivers Arges (Romania), Timok (Bulgaria), Rusenski Lom (Bulgaria), and Velika Morava (Serbia). PMID:20074769

Loos, Robert; Locoro, Giovanni; Contini, Serafino

2010-01-04

293

Novel magnetic SPE method based on carbon nanotubes filled with cobalt ferrite for the analysis of organochlorine pesticides in honey and tea.  

PubMed

A novel magnetic SPE method based on magnetic cobalt ferrite filled carbon nanotubes (MFCNTs) coupled with GC with electron capture detection was developed to determine organochlorine pesticides (OCPs) in tea and honey samples. The MFCNTs were prepared through the capillarity of carbon nanotubes for drawing mixed cobalt and iron nitrates solution into their inner cavity followed by heating to 550°C under Ar to form the cobalt ferrite nanoparticles. SEM images provided visible evidence of the filled cobalt ferrite nanoparticles in the multiwalled nanotubes. X-ray photoelectron spectroscopy indicated no adhesion of cobalt ferrite nanoparticles and metal salts on the outer surface of the MFCNTs. Eight OCPs were extracted with the MFCNTs. The enrichment factors were in the range of 52-68 for eight OCPs. The LODs for the eight OCPs were in the range of 1.3-3.6 ng/L. The recoveries of the OCPs for honey and tea samples were 83.2-128.7 and 72.6-111.0%, respectively. The RSDs for these samples were below 6.8%. The new method is particularly suited to extract nonpolar and weakly polar analytes from a complex matrix and could potentially be extended to other target analytes. PMID:23926126

Du, Zhuo; Liu, Miao; Li, Gongke

2013-09-01

294

Rapid and selective quantification of L-theanine in ready-to-drink teas from Chinese market using SPE and UPLC-UV.  

PubMed

An ultra performance liquid chromatography (UPLC) method combined with solid phase extraction (SPE) sample pre-treatment was developed and validated for the rapid quantification of L-theanine in ready-to-drink (RTD) teas. UPLC analysis of twenty-seven RTD teas from the Chinese market revealed that the L-theanine levels in various types of RTD teas were significantly different. RTD green teas were found to contain highest mean L-theanine level (37.85±20.54 mg/L), followed by jasmine teas (36.60±12.08 mg/L), Tieguanying teas (18.54±3.46 mg/L) black teas (16.89±6.56), Pu-erh teas (11.31±0.90 mg/L) and oolong teas (3.85±2.27 mg/L). The ratio of total polyphenols content to L-theanine content could be used as a featured parameter for differentiating RTD teas. L-theanine in RTD teas could be a reliable quality parameter that is complementary to total polyphenols. PMID:22868106

Chen, Guoqiang; Wang, Yun; Song, Weiqi; Zhao, Bo; Dou, Yuling

2012-04-30

295

Effects of ginsenoside Rg2 on the ultraviolet B-induced DNA damage responses in HaCaT cells.  

PubMed

Our previous study demonstrated the increase in the repair of UVB damage by mRg2, a mixture of ginsenosides containing 60% Rg2 in NIH3T3 cells. In the present study, the effects of purified Rg2 on the repair and apoptosis in ultraviolet B (UVB)-exposed HaCaT cells were investigated on gene expression levels. When cells were exposed to UVB and post-incubated in normal medium for 24 h, the cell viability decreased to about 50% of that in nontreated control. When Rg2 was post-incubated, however, the UVB-induced cytotoxicity was significantly prevented in an Rg2 concentration- and time-dependent manner. The apoptotic nuclear fragmentation resulting from UVB exposure was also significantly protected by the Rg2 post-incubation. Microarray analysis showed that the genes stimulated by the Rg2-alone treatment include those involved in p53 signaling pathway such as GADD45alpha, GADD45beta, and cell communication genes. RT-PCR analysis showed that the Rg2-alone treatment slightly upregulated the p53 and GADD45 transcript and protein levels by about 1.5-fold as compared with the nontreated control. The mRNA levels of p53 and GADD45 in cells exposed to UVB and post-incubated with Rg2 for 24 h decreased in an Rg2 concentration-dependent manner as compared with that post-incubated in normal medium. However, the mRNA level of the UVB-exposed cells post-incubated with 5 microM retinol was essentially the same as that post-incubated in normal medium. Time course experiment showed that the mRNA levels of p53 and GADD45 in UVB-exposed cells were upregulated by post-incubation with 50 microM Rg2 until 6 and 9 h, respectively, and then gradually decreased until 24 h. By Western blot analysis, it was also revealed that the Rg2 post-incubation decreases the expression of p53, phospho-p53, GADD45, and ATM in UVB-exposed cells. Time course analysis also indicated that these decreased expressions were due to the earlier upregulation of p53 and GADD45 proteins. When UVB-exposed cells were post-incubated with Rg2 for 24 h after UVB exposure, the level of remaining cyclobutane pyrimidine dimers decreased in both Rg2 concentration- and time-dependent manner. All these results suggest that Rg2 protects cells against UVB-induced genotoxicity by increasing DNA repair, in possible association with modulation of protein levels involved in p53 signaling pathway. PMID:20508917

Ha, Se Eun; Shin, Dae Hyun; Kim, Hyung Do; Shim, Sun Mi; Kim, Hack Soo; Kim, Bo Hyeon; Lee, Jung Sup; Park, Jong Kun

2010-05-28

296

Apoptosis: a guide for the perplexed.  

PubMed

The term 'apoptosis' describes an active process of cellular deconstruction originally contrasted morphologically with necrosis. The mistaken equivalence of the terms apoptosis and 'programmed cell death' has caused confusion and implied that apoptosis is an identifiable therapeutic target rather than a name of a type of cell death. The roots of confusion are suggested to lie not in superficial disagreements about the morphology and biochemistry of cell death, but in the lamentable disconnection of modern science from its philosophical foundations (i.e. Socratic definition, nominalism versus realism, and William of Ockham's advocacy of Aristotelian metaphysics over Plato's Theory of Forms). Renewed awareness of these issues might be the key to understanding that apoptosis is a created concept, not a real entity, and that the use of terms that defy definition has become an obstacle to clear thinking about preventable cell death. PMID:11804647

Sloviter, Robert S

2002-01-01

297

Molecular Analysis of Neurotoxin-Induced Apoptosis.  

National Technical Information Service (NTIS)

Apoptosis is a cell-suicide process that is required for the normal development of the nervous system, but that can be aberrantly activated in neurodegenerative diseases and following exposure to neurotoxins. The intracellular pathways by which these diff...

S. R. D'Mello

2006-01-01

298

Sphingosine kinase, sphingosine-1-phosphate, and apoptosis  

Microsoft Academic Search

The sphingolipid metabolites ceramide (Cer), sphingosine (Sph), and sphingosine-1-phosphate (S1P) play an important role in the regulation of cell proliferation, survival, and cell death. Cer and Sph usually inhibit proliferation and promote apoptosis, while the further metabolite S1P stimulates growth and suppresses apoptosis. Because these metabolites are interconvertible, it has been proposed that it is not the absolute amounts of

Michael Maceyka; Shawn G Payne; Sheldon Milstien; Sarah Spiegel

2002-01-01

299

APOPTOSIS: A Cinderella Caspase Takes Center Stage  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. It has been thought that permeabilization of mitochondria and release of cytochrome c is an early event in apoptosis that is required for activation of caspases, the enzyme executioners of the apoptotic cascade. However, in a Perspective, Kumar and Vaux explain new findings (Lassus et al.) that implicate an often ignored caspase, caspase-2, in the early stages of apoptosis prior to mitochondrial permeabilization.

Sharad Kumar (Hanson Institute;); David L. Vaux (Walter and Eliza Hall Institute;)

2002-08-23

300

Nutrient availability links mitochondria, apoptosis, and obesity  

PubMed Central

Mitochondria are the dominant source of the cellular energy requirements through oxidative phosphorylation, but they are also central players in apoptosis. Nutrient availability may have been the main evolutionary driving force behind these opposite mitochondrial functions: production of energy to sustain life and release of apoptotic proteins to trigger cell death. Here, we explore the link between nutrients, mitochondria and apoptosis with known and potential implications for age-related decline and metabolic syndromes.

Pintus, Francesca; Floris, Giovanni; Rufini, Alessandro

2012-01-01

301

Genetic Defects of Apoptosis and Primary Immunodeficiency  

PubMed Central

Synopsis Programmed cell death is important for maintaining lymphocyte homeostasis. Several human inherited diseases with impaired apoptosis have been identified at the genetic level: autoimmune lymphoproliferative syndrome (ALPS), caspase-8 deficiency state (CEDS), and X-linked lymphoproliferative syndrome (XLP). These diseases feature excess lymphocyte accumulation, autoimmunity, and/or immunodeficiency. Elucidating their molecular pathogenesis has also provided new insights into the signaling mechanisms regulating apoptosis and lymphocyte activation.

Su, Helen C.; Lenardo, Michael J.

2009-01-01

302

Placental apoptosis in normal human pregnancy  

Microsoft Academic Search

OBJECTIVES: The study aims were to conclusively demonstrate apoptosis in the human placenta and to quantify its incidence at different stages of pregnancy. STUDY DESIGN: Placental samples were obtained from 28 first-trimester pregnancies and 38 uncomplicated third-trimester pregnancies. Light microscopy, electron microscopy, and terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate marker nick end-labeling staining were used to identify apoptosis. Light microscopy was

Stephen Smith; Philip N. Baker; E. Malcolm Symonds

1997-01-01

303

Morphologic criteria and detection of apoptosis  

Microsoft Academic Search

Apoptosis is an organized, energy dependent process, which leads to cell death. Its definition is based on distinct morphological\\u000a features [10] and demonstration of internucleosomal DNA degradation [27], executed by selectively activated DNAses [4, 22].\\u000a The morphologic hallmarks of apoptosis include chromatic margination, nuclear condensation and fragmentation, and condensation\\u000a of the cell with preservation of organelles. The process is followed

Antti Saraste

1999-01-01

304

Apoptosis in Cancer Biology and Cancer Therapeutics  

Microsoft Academic Search

Most anticancer therapies commonly used in the treatment of human cancer, e.g., chemotherapy, ?-irradiation, immunotherapy,\\u000a or suicide gene therapy, kill tumor cells by triggering cell death pathways including apoptosis in cancer cells. Hence, the\\u000a failure to activate such pathways may lead to the resistance of cancers to current treatment approaches. A better understanding\\u000a of the molecular events that regulate apoptosis

Simone Fulda

305

TNF-Induced Signaling in Apoptosis  

Microsoft Academic Search

Out of the almost 17 members of the TNF superfamily, TNF is probably the most potent inducer of apoptosis. TNF activates both cell-survival and cell-death mechanisms simultaneously. Activation of NF-kB-dependent genes regulates the survival and proliferative effects pf TNF, whereas activation of caspases regulates the apoptotic effects. TNF-induced apoptosis is mediated primarily through the activation of type I receptors, the

Pramod C. Rath; Bharat B. Aggarwal

1999-01-01

306

Keratocyte Apoptosis and Failure of Corneal Allografts  

PubMed Central

Background Murine models of high-risk and low-risk corneal transplantation were used to determine the role of keratocyte apoptosis in the failure of orthotopic allogeneic corneal transplants. Materials and Methods Normal (low-risk, low-rejecting) and inflamed/vascularized (high-risk, high-rejecting) BALB/c recipient beds received fully mismatched C57BL/6 corneal allografts. Apoptosis was detected in the corneal stroma at various time points using an in situ terminal deoxynucleotide tranferase-mediated dUTP nick-end labeling assay, and ex vivo via Western analysis for active caspase-3. Apoptosis was also measured in a (donor-type) C57BL/6 keratocyte cell line after stimulation of Fas or via use of various pro-inflammatory cytokines. Results Significantly more apoptotic cells were present in the stroma of rapidly rejecting high-risk corneal allografts compared with low-risk grafts. Apoptotic cells were shown to be nearly uniformly CD45? and hence of a non-hematopoetic lineage. Apoptosis, however, was not present in highly inflamed but ungrafted corneas. Apoptosis was induced in keratocytes in vitro by dual stimulation with agonistic Fas mAb and either interleukin-1? or tumor necrosis factor-?. Conclusion Apoptosis of resident non-bone marrow-derived fibroblastic cells of the corneal stroma is strongly correlated with the failure of corneal allografts, particularly in the highly inflamed microenvironment of the high-risk allograft.

Beauregard, Clay; Huq, Syed O.; Barabino, Stefano; Zhang, Qiang; Kazlauskas, Andrius; Dana, M. Reza

2006-01-01

307

Physalin B from Physalis angulata triggers the NOXA-related apoptosis pathway of human melanoma A375 cells.  

PubMed

Melanoma is a lethal form of skin cancer that can metastasize rapidly. While surgery and radiation therapy provide palliative therapy for local tumor growth, systemic therapy is the mainstay of treatment for metastatic melanoma. However, limited chemotherapeutic agents are available for melanoma treatment. In this study, we investigated the anti-melanoma effect of physalin B, the major active compound from a widely used herb medicine, Physalis angulata L. This study demonstrated that physalin B exhibits cytotoxicity towards v-raf murine sarcoma viral oncogene homolog B1 (BRAF)-mutated melanoma A375 and A2058 cells (the IC50 values are lower than 4.6 ?g/ml). Cytotoxicity is likely resulted from apoptosis since the apoptotic marker phosphatidylserine are detected immediately under physalin B treatment and apoptotic cells formation. Further examination revealed that physalin B induces expression of the proapoptotic protein NOXA within 2 h and later triggers the expression of Bax and caspase-3 in A375 cells. These results indicate that physalin B can induce apoptosis of melanoma cancer cells via the NOXA, caspase-3, and mitochondria-mediated pathways, but not of human skin fibroblast cells and myoblastic cells. Thus, physalin B has the potential to be developed as an effective chemotherapeutic lead compound for the treatment of malignant melanoma. PMID:22245079

Hsu, Chia-Chun; Wu, Yang-Chang; Farh, Lynn; Du, Ying-Chi; Tseng, Wei-Kung; Wu, Chau-Chung; Chang, Fang-Rong

2012-01-08

308

SPE-HPLC method for the determination of four flavonols in rat plasma and urine after oral administration of Abelmoschus manihot extract.  

PubMed

A SPE-HPLC method was developed and validated for the simultaneous determination of flavonols, isoquercitrin (1), hibifolin (2), myricetin (3), quercetin-3'-O-d-glucoside (4) and quercetin (5) in rat plasma and urine after oral administration of the total flavonoids from Abelmoschus manihot (TFA). The astragalin (6) and kaempferol (7) were used as internal standards (IS). Plasma and urine samples were pretreated by solid-phase extraction using Winchem C(18) reversed-phase cartridges. Analysis of the plasma and urinary extract was performed on YMC-Pack ODS-A C(18) and Thermo ODS-2HYEPRSIL C(18) reversed-phase column, respectively and a mobile phase of acetonitrile-0.1% phosphoric acid was employed. HPLC analysis was conducted with different elution gradients. The flow rate was 1.0 mL/min and the detection wavelength was set at 370 nm. Calibration ranges in plasma for flavonols 2-5 were at 0.011-2.220, 0.014-2.856, 0.022-4.320, and 0.028-5.600 microg/mL, respectively. In urine calibration ranges for flavonols 1, 2, 4 and 5 were at 2.00-16.00, 8.56-102.72, 2.70-21.60, and 3.00-24.00 microg/mL, respectively. The RSD of intra- and inter-day was less than 5.40% and 4.89% in plasma, and less than 3.96% and 6.85% in urine for all the analyses. A preliminary experiment to investigate the plasma concentration and urinary excretion of the flavonols after oral administration of TFA to rats demonstrated that the present method was suitable for determining the flavonols in rat plasma and urine. PMID:17258944

Lai, Xianyin; Zhao, Yuying; Liang, Hong; Bai, Yanjing; Wang, Bin; Guo, Dean

2007-01-10

309

Determination of six phthalic acid esters in orange juice packaged by PVC bottle using SPE and HPLC-UV: application to the migration study.  

PubMed

A high-performance liquid chromatographic assay is described for the determination of six phthalic acid esters (PAEs) in orange juice packaged in polyvinyl chloride (PVC) bottle. Samples were extracted by solid-phase extraction (SPE) cartridges and separated by a C?? column. The calibration curves were all linear with a correlation coefficient r > 0.9900. The limits of detection for the assay ranged from 2.6 to 13.8 ng/mL. Expressed as the within- and between-day coefficient of variation (CV), precision was 1.4-13.4% and 1.9-13.3%, respectively, and relative errors were 7.6-12.8% and -9.0-14.2%, respectively. The recovery ranged from 76.8 to 112.3% with the CV from 0.3 to 11.3%. The proposed methodology was applied for studing the migration of the selected PAEs into orange juice packaged in PVC bottle. Di-ethyl phthalate (DEP) and di-(2-ethylhexyl) phthalate (DEHP) were detected in the orange juice without the other four PAEs. Concentrations would increase with the storage time and reach up to 0.385 ?g/mL and 0.662 ?g/mL, respectively, when the expiration date arrived. The level of DEHP was about 110 times higher than the limiting one in drink water (6 ppb) regulated by U.S. EPA. Results suggest that PVC plasticized by DEHP should not be used as the packaging material for orange juice. PMID:20875239

Guo, Zhiyong; Wei, Danyi; Wang, Meili; Wang, Sui

2010-10-01

310

1H NMR-based metabolomics combined with HPLC-PDA-MS-SPE-NMR for investigation of standardized Ginkgo biloba preparations  

PubMed Central

Commercial preparations of Ginkgo biloba are very complex mixtures prepared from raw leaf extracts by a series of extraction and prepurification steps. The pharmacological activity is attributed to a number of flavonoid glycosides and unique terpene trilactones (TTLs), with largely uncharacterized pharmacological profiles on targets involved in neurological disorders. It is therefore important to complement existing targeted analytical methods for analysis of Ginkgo biloba preparations with alternative technology platforms for their comprehensive and global characterization. In this work, 1H NMR-based metabolomics and hyphenation of high-performance liquid chromatography, photo-diode array detection, mass spectrometry, solid-phase extraction, and nuclear magnetic resonance spectroscopy (HPLC-PDA-MS-SPE-NMR) were used for investigation of 16 commercially available preparations of Ginkgo biloba. The standardized extracts originated from Denmark, Italy, Sweden, and United Kingdom, and the results show that 1H NMR spectra allow simultaneous assessment of the content as well as identity of flavonoid glycosides and TTLs based on a very simple sample-preparation procedure consisting of extraction, evaporation and reconstitution in acetone-d6. Unexpected or unwanted extract constituents were also easily identified in the 1H NMR spectra, which contrasts traditional methods that depend on UV absorption or MS ionizability and usually require availability of reference standards. Automated integration of 1H NMR spectral segments (buckets or bins of 0.02 ppm width) provides relative distribution plots of TTLs based on their H-12 resonances. The present study shows that 1H NMR-based metabolomics is an attractive method for non-selective and comprehensive analysis of Ginkgo extracts. Electronic supplementary material The online version of this article (doi:10.1007/s11306-009-0195-x) contains supplementary material, which is available to authorized users.

Agnolet, Sara; Jaroszewski, Jerzy W.; Verpoorte, Robert

2010-01-01

311

Trauma patients' elevated tumor necrosis related apoptosis inducing ligand (TRAIL) contributes to increased T cell apoptosis.  

PubMed

Immunosuppression resulting from excessive post-trauma apoptosis of hyperactivated T cells is controversial. TRAIL mediated T cell apoptosis decreases highly activated T cells' responses. Caspase-10, a particular TRAIL target, was increased in trauma patients' T cells with concomitantly elevated plasma TRAIL levels. These patients' T cells developed anergy, implicating increased TRAIL-mediated T cell apoptosis in post-trauma T cell anergy. Control T cells cultured with patients' sera containing high TRAIL levels increased their caspase-10 activity and apoptosis. Stimulated primary T cells are TRAIL apoptosis resistant. Increased plasma thrombospondin-1 and T cell expression of CD47, a thrombospondin-1 receptor, preceded patients' T cell anergy. CD47 triggering of T cells increased their sensitivity to TRAIL-induced apoptosis. Augmentation of T cell TRAIL-induced apoptosis was secondary to CD47 triggered activation of the Src homology-containing phosphatase-1 (SHP-1) and was partially blocked by a SHP-1 inhibitor. We suggest that combined post-trauma CD47 triggering, SHP-1 mediated NF?B suppression, and elevated TRAIL levels increase patients' CD47 expressing T cell apoptosis, thus contributing to subsequent T cell anergy. PMID:22926077

Bandyopadhyay, Gautam; Bankey, Paul E; Miller-Graziano, Carol L

2012-08-03

312

Trauma patients' elevated Tumor Necrosis Related Apoptosis Inducing Ligand (TRAIL) contributes to increased T cell apoptosis  

PubMed Central

Immunosuppression resulting from excessive post-trauma apoptosis of hyperactivated Tcells is controversial. TRAIL mediated Tcell apoptosis decreases highly activated Tcells’ responses. Caspase-10, a particular TRAIL target, was increased in trauma patients’ Tcells with concomitantly elevated plasma TRAIL levels. These patients’ Tcells developed anergy, implicating increased TRAIL-mediated Tcell apoptosis in post-trauma Tcell anergy. Control Tcells cultured with patients’ sera containing high TRAIL levels increased their Caspase-10 activity and apoptosis. Stimulated primary Tcells are TRAIL apoptosis resistant. Increased plasma Thrombospondin-1 and Tcell expression of CD47, a Thrombospondin-1 receptor, preceded patients’ Tcell anergy. CD47 triggering of Tcells increased their sensitivity to TRAIL-induced apoptosis. Augmentation of Tcell TRAIL-induced apoptosis was secondary to CD47 triggered activation of the Src homology-containing phosphatase-1(SHP-1) and was partially blocked by a SHP-1 inhibitor. We suggest that combined post-trauma CD47 triggering, SHP-1 mediated NF?B suppression, and elevated TRAIL levels increase patients’ CD47 expressing Tcell apoptosis, thus contributing to subsequent Tcell anergy.

Bandyopadhyay, Gautam; Bankey, Paul E.; Miller-Graziano, Carol L.

2012-01-01

313

Nicotine Promotes Cardiomyocyte Apoptosis via Oxidative Stress and Altered Apoptosis-Related Gene Expression  

Microsoft Academic Search

Objective: To investigate the effect of nicotine on cardiomyocyte apoptosis in vitro and explore the potential mechanisms involved. Methods: The MTT assay was used to detect the viability of cultured cardiomyocytes exposed to different concentrations of nicotine (0.1–100 ?M). Laser confocal microscopy, TUNEL assay and flow cytometry were utilized to detect cardiomyocyte apoptosis. Oxidative stress was evaluated by the levels

Xiang Zhou; Yanhui Sheng; Rong Yang; Xiangqing Kong

2010-01-01

314

Adrenergic regulation of cardiac myocyte apoptosis.  

PubMed

The direct effects of catecholamines on cardiac myocytes may contribute to both normal physiologic adaptation and pathologic remodeling, and may be associated with cellular hypertrophy, apoptosis, and alterations in contractile function. Norepinephrine (NE) signals via alpha- and beta-adrenergic receptors (AR) that are coupled to G-proteins. Pharmacologic studies of cardiac myocytes in vitro demonstrate that stimulation of beta1-AR induces apoptosis which is cAMP-dependent and involves the voltage-dependent calcium influx channel. In contrast, stimulation of beta2-AR exerts an anti-apoptotic effect which appears to be mediated by a pertussis toxin-sensitive G protein. Stimulation of alpha1-AR causes myocyte hypertrophy and may exert an anti-apoptotic action. In transgenic mice, myocardial overexpression of either beta1-AR or G(alpha)s is associated with myocyte apoptosis and the development of dilated cardiomyopathy. Myocardial overexpression of beta2-AR at low levels results in improved cardiac function, whereas expression at high levels leads to dilated cardiomyopathy. Overexpression of wildtype alpha1B-AR does not result in apoptosis, whereas overexpression of G(alpha)q results in myocyte hypertrophy and/or apoptosis depending on the level of expression. Differential activation of the members of the mitogen-activated protein kinase (MAPK) superfamily and production of reactive oxygen species appear to play a key role in mediating the actions of adrenergic pathways on myocyte apoptosis and hypertrophy. This review summarizes current knowledge about the molecular and cellular mechanisms involved in the regulation of cardiac myocyte apoptosis via stimulation of adrenergic receptors and their coupled effector pathways. PMID:11748583

Singh, K; Xiao, L; Remondino, A; Sawyer, D B; Colucci, W S

2001-12-01

315

CASPASE CONTROL: PROTAGONISTS OF CANCER CELL APOPTOSIS  

PubMed Central

Emergence of castration-resistant metastatic prostate cancer is due to activation of survival pathways, including apoptosis suppression and anoikis resistance, and increased neovascularization. Thus targeting of apoptotic players is of critical significance in prostate cancer therapy since loss of apoptosis and resistance to anoikis are critical in aberrant malignant growth, metastasis and conferring therapeutic failure. The majority of therapeutic agents act through intrinsic mitochondrial, extrinsic death receptor pathways or endoplasmic reticulum stress pathways to induce apoptosis. Current therapeutic strategies target restoring regulatory molecules that govern the pro-survival pathways such as PTEN which regulates AKT activity. Other strategies focus on reactivating the apoptotic pathways either by down-regulating anti-apoptotic players such as BCL-2 or by up-regulating pro-apoptotic protein families, most notably, the caspases. Caspases are a family of cystine proteases which serve critical roles in apoptotic and inflammatory signaling pathways. During tumorigenesis, significant loss or inactivation of lead members in the caspase family leads to impairing apoptosis induction, causing a dramatic imbalance in the growth dynamics, ultimately resulting in aberrant growth of human cancers. Recent exploitation of apoptosis pathways towards re-instating apoptosis induction via caspase re-activation has provided new molecular platforms for the development of therapeutic strategies effective against advanced prostate cancer as well as other solid tumors. This review will discuss the current cellular landscape featuring the caspase family in tumor cells and their activation via pharmacologic intervention towards optimized anti-cancer therapeutic modalities. This article is part of a Special Issue entitled “Apoptosis: Four Decades Later”.

Fiandalo, M.V.; Kyprianou, N.

2013-01-01

316

[Depression and treatment. Apoptosis, neuroplasticity and antidepressants].  

PubMed

Depression's neurobiology begins to be better understood. The last decade data considers neuroplasticity and stress as implicated factors on the pathophisiology of depression. Because antidepressants have a lag-time on their action it is possible that inhibition of neurotransmitters recaptation is not sufficient to explain long term changes. For that purpose, neurogenesis increase, nervous fibers sprouting, new synapses and stabilization of the old ones can be responsible for those changes. AMPc-MAPcinases-CREB-BDNF cellular cascade can play a significant role in the mechanisms of dendritic restructuration, hippocampal neurogenesis increase and nervous cells survival. The aim of this article is to discuss if apoptosis could play a key role as an ethiopathogenic factor on the patogenesis of depression. It was done a medline search for references with apoptosis, stress, neuroplasticity, depression and antidepressants key-words. It were found 101 original or review references about these subjects. Stress plays a key role in the etiopathogeny of depression. Its deletery effects on apoptosis and neuroplasticity can be changed by antidepressants. Neurogenesis' increase is necessary for their action. This increase is reached with chronic antidepressant treatment and not with other psychotropic drugs which means some pharmacological specificity of antidepressants. AMPc, CREB, BDNF and Bcl-2 can be considered as target genes in antidepressant synthesis. At the level of this neurotrophic factors apoptosis might be included in the neuroplastic model of depression and play a prominent role in etiopathogeny of depression. To confirm that, we need more research on the field to know which are the mechanisms that trigger apoptosis and its biological significance. In relation to the last one, we can say that is possible to be physiological apoptosis in deteriorated neurons death which cannot make strong connections and pathological apoptosis because of stress via, namely, HPA axis. PMID:16987439

Arantes-Gonçalves, Filipe; Coelho, Rui

2006-04-30

317

AMPK activator, AICAR, inhibits palmitate-induced apoptosis in osteoblast.  

PubMed

Osteoblast apoptosis reduces bone mineral density. Apoptosis can be induced in a variety of cells by palmitate, which is one of the most common saturated fatty acids in dietary fat. The AMPK activator, AICAR, has been shown to inhibit palmitate-induced apoptosis. However, the role of palmitate in osteoblast apoptosis is currently unknown. This study examined whether palmitate could induce apoptosis in osteoblasts, and if so, whether AICAR could alleviate palmitate-induced apoptosis. Palmitate reduced cell survival and induced apoptosis in a dose- and time-dependent manner in human fetal osteoblasts (hFOB) 1.19. While the long-chain acyl-CoA synthetase inhibitor, triacsin C, inhibited palmitate-induced apoptosis, anti-oxidants and ceramide synthesis inhibitors did not attenuate the apoptosis. AICAR prevented palmitate-induced apoptosis and the inhibition of AICAR-mediated increase in fatty acid oxidation by etomoxir did not affect the prevention of apoptosis by AICAR. Constitutively-active AMPK also inhibited palmitate-induced apoptosis. Treatment with an AMPK inhibitor (compound C) and a dominant-negative AMPK adenovirus suppressed the inhibitory effect of AICAR on apoptosis. Palmitate impaired the activation of ERK by fetal bovine serum, which was blocked by AICAR. Moreover, AICAR increased ERK activation, and ERK inhibitors, PD98059 and U0126, as well as a dominant-negative MEK1, abolished the inhibitory effect of AICAR on palmitate-induced apoptosis. AICAR also inhibited palmitate-induced apoptosis in osteoblastic differentiated cells from human bone marrow, which was accompanied by recovered ERK activity. These results suggest that palmitate induces apoptosis in osteoblasts through the impaired activation of ERK, and the activation of AMPK inhibits palmitate-induced apoptosis by activating ERK. PMID:18502715

Kim, Ji-Eun; Ahn, Myun-Whan; Baek, Suk-Hwan; Lee, In Kyu; Kim, Yong-Woon; Kim, Jong-Yeon; Dan, Jin-Myoung; Park, So-Young

2008-04-10

318

Apoptosis - an Ubiquitous T cell Immunomodulator  

PubMed Central

Apoptosis is a natural process where cells that are no longer required can be eliminated in a highly regulated, controlled manner. Apoptosis is important in maintaining the mammalian immune system and plays a significant role in immune response, positive and negative T cell selection, and cytotoxic death of target cells. When the apoptotic pathways are impaired or are not tightly regulated, autoimmune diseases, inflammatory diseases, viral and bacterial infections and cancers ensue. An imbalance in the anti-apoptotic and pro-apoptotic factors has been implicated in these diseases. Moreover, current therapies directed towards these diseases focus on the modulation of the apoptotic death pathways to regulate the immune response. In this review, we will focus on the process of T cell activation and apoptosis in autoimmune reactions, in response to tumor progression as well as in response to bacterial and viral infections.

Murali, Anuradha K.; Mehrotra, Shikhar

2013-01-01

319

Nickel induces apoptosis in human neutrophils.  

PubMed

Nickel is an ubiquitous transition metal that is industrially applied in many forms, which inevitably leads to a high degree of occupational and environmental exposure. Over-exposure to nickel can produce a variety of adverse effects on human health, including allergy and lung and nasal cancers. In the present study, it is demonstrated, for the first time, that nickel [(Ni(II)] (as a nickel nitrate salt) at concentrations that may be attained in vivo, induces neutrophils' apoptosis by the intrinsic pathway. The use of diphenyleneiodonium, a NADPH oxidase inhibitor, delayed Ni(II)-induced apoptosis, suggesting that NADPH oxidase-derived reactive oxygen species and subsequent signaling could contribute to this event. This is an important finding since increased apoptosis mediated by nickel may disrupt the physiological activities of neutrophils, with potential impact in its immunological and antimicrobial role. PMID:23097079

Freitas, Marisa; Barcellos-de-Souza, Pedro; Barja-Fidalgo, Christina; Fernandes, Eduarda

2012-10-25

320

Mitochondrial Dysfunction in Lyssavirus-Induced Apoptosis? †  

PubMed Central

Lyssaviruses are highly neurotropic viruses associated with neuronal apoptosis. Previous observations have indicated that the matrix proteins (M) of some lyssaviruses induce strong neuronal apoptosis. However, the molecular mechanism(s) involved in this phenomenon is still unknown. We show that for Mokola virus (MOK), a lyssavirus of low pathogenicity, the M (M-MOK) targets mitochondria, disrupts the mitochondrial morphology, and induces apoptosis. Our analysis of truncated M-MOK mutants suggests that the information required for efficient mitochondrial targeting and dysfunction, as well as caspase-9 activation and apoptosis, is held between residues 46 and 110 of M-MOK. We used a yeast two-hybrid approach, a coimmunoprecipitation assay, and confocal microscopy to demonstrate that M-MOK physically associates with the subunit I of the cytochrome c (cyt-c) oxidase (CcO) of the mitochondrial respiratory chain; this is in contrast to the M of the highly pathogenic Thailand lyssavirus (M-THA). M-MOK expression induces a significant decrease in CcO activity, which is not the case with M-THA. M-MOK mutations (K77R and N81E) resulting in a similar sequence to M-THA at positions 77 and 81 annul cyt-c release and apoptosis and restore CcO activity. As expected, the reverse mutations, R77K and E81N, introduced in M-THA induce a phenotype similar to that due to M-MOK. These features indicate a novel mechanism for energy depletion during lyssavirus-induced apoptosis.

Gholami, Alireza; Kassis, Raid; Real, Eleonore; Delmas, Olivier; Guadagnini, Stephanie; Larrous, Florence; Obach, Dorothee; Prevost, Marie-Christine; Jacob, Yves; Bourhy, Herve

2008-01-01

321

Chondrocyte apoptosis induced by nitric oxide.  

PubMed Central

Chondrocytes stimulated with IL-1 produce high levels of nitric oxide (NO), which inhibits proliferation induced by transforming growth factor-beta or serum. This study analyzes the role of NO and IL-1 in the induction of chondrocyte cell death. NO generated from sodium nitroprusside induced apoptosis in cultured chondrocytes as demonstrated by electron microscopy, 4',6-dianidino-2-phenylindole dihydrochloride staining, FACS analysis, and histochemical detection of DNA fragmentation. Similar results were obtained with two other NO donors, 3-morpholinosynonimide-hydrochloride and s-nitroso-N-acetyl-D-L-penicillamine. In contrast, oxygen radicals generated by hypoxanthine/xanthine oxidase caused necrosis but did not induce chondrocyte apoptosis. To analyze whether endogenously generated NO induces apoptosis, chondrocytes were stimulated with IL-1, but there was no evidence for apoptotic changes. Combinations of NO inducers such as IL-1, lipopolysaccharide, tumor necrosis factor, and interferon-gamma also failed to trigger apoptosis. IL-1-stimulated chondrocytes are known to produce oxygen radicals that react with NO to form products that can induce cell death in other systems. We thus tested IL-1 in combination with the oxygen radical scavengers N-acetyl cysteine, dimethyl sulfoxide, or 5,5'-dimetylpyrroline 1-oxide. Under these conditions IL-1 was able to induce apoptosis, which was inhibited in a dose-dependent manner by the NO synthase inhibitor N-monomethyl L-arginine. Conversely, endogenous oxygen radicals induced by inflammatory mediators caused necrosis under conditions in which the simultaneous production of NO was reduced. These results suggest that NO, but not oxygen radicals, is the primary inducer of apoptosis in human articular chondrocytes. Images Figure 1 Figure 2 Figure 4 Figure 7

Blanco, F. J.; Ochs, R. L.; Schwarz, H.; Lotz, M.

1995-01-01

322

APOPTOSIS: Mitochondria--the Death Signal Integrators  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Many of the intricate pathways of apoptosis that instruct a cell to kill itself involve the convergence of key proteins on the membranes of mitochondria. Such proteins induce the permeabilization of mitochondrial membranes and the release of caspase enzymes and nuclease activators that set in motion the final stages of programmed cell death. Now, as Brenner and Kroemer discuss in their Perspective, a proapoptotic transcription factor called TR3 has been found to move from its normal location in the nucleus to the mitochondria and to promote release of cytochrome c, a key event in apoptosis (Li et al.)

Catherine Brenner (Institut Gustave Roussy; Université de Technologie de Compiègne ;Apoptosis, Cancer and Immunity Laboratory associated with the National League Against Cancer); Guido Kroemer (Institut Gustave Roussy; Université de Technologie de Compiègne ;Apoptosis, Cancer and Immunity Laboratory associated with the National League Against Cancer)

2000-08-18

323

ICE/CED-3 proteasesin apoptosis.  

PubMed

An expanding family of cysteine proteases, of which interleukin-1beta-converting enzyme (ICE) is the prototype, has been shown to play a key role in mammalian cell apoptosis. ICE is both a structural and functional homologue of the nematode 'death gene' ced-3. Here, Moira Whyte discusses how functional characterization of these ICE-like proteases and identification of their substrates is helping to elucidate the biochemical processes underlying the stereotyped morphology of apoptosis and to identify potential targets for therapy. PMID:15157443

Whyte, M

1996-07-01

324

Signalling steps in apoptosis by ether lipids  

Microsoft Academic Search

We have investigated the mechanisms of induction of apoptosis by the antineoplastic ether lipid ET-18-OCH3 (ALP) in sensitive S49wt mouse lymphoma cells and ALP-resistant S49ar variants, both with wild-type p53, and in related L1210 cells with mutated p53. Ether lipid-resistant S49ar cells were cross-resistant to extracellular stress factors (cold shock, heat shock, H2O2, dimethylsulfoxide) and to radiation-induced apoptosis but not

L. A. Smets; H. Van Rooij; G. S. Salomons

1999-01-01

325

Trolox Inhibits Apoptosis in Irradiated MOLT-4 Lymphocytes.  

National Technical Information Service (NTIS)

MOLT-4 cells, a human lymphocytic leukemia line, undergo apoptosis in response to a variety of stimuli, including exposure to ionizing radiation. Very little is known of the molecular mechanisms by which radiation induces apoptosis. Morphology changes and...

D. E. McClain J. F. Kalinich N. Ramakrishnan

1995-01-01

326

Apoptosis signal-regulating kinase 1 mediates denbinobin-induced apoptosis in human lung adenocarcinoma cells  

Microsoft Academic Search

In the present study, we explore the role of apoptosis signal-regulating kinase 1 (ASK1) in denbinobin-induced apoptosis in human lung adenocarcinoma (A549) cells. Denbinobin-induced cell apoptosis was attenuated by an ASK1 dominant-negative mutant (ASK1DN), two antioxidants (N-acetyl-L-cysteine (NAC) and glutathione (GSH)), a c-Jun N-terminal kinase (JNK) inhibitor (SP600125), and an activator protein-1 (AP-1) inhibitor (curcumin). Treatment of A549 cells with

Chen-Tzu Kuo; Bing-Chang Chen; Chung-Chi Yu; Chih-Ming Weng; Ming-Jen Hsu; Chien-Chih Chen; Mei-Chieh Chen; Che-Ming Teng; Shiow-Lin Pan; Mauo-Ying Bien; Chung-Hung Shih; Chien-Huang Lin

2009-01-01

327

Growth Inhibition and Apoptosis-Inducing Effects of Cudraflavone B in Human Oral Cancer Cells via MAPK, NF-?B, and SIRT1 Signaling Pathway.  

PubMed

The goal of this study was to investigate the effect and molecular mechanism of cudraflavone B, a prenylated flavonoid isolated from the root bark of Cudrania tricuspidata, against oral squamous cell carcinoma cells. We observed that cudraflavone B inhibited proliferation of these cells in a time- and dose-dependent manner. At 15 µM, cudraflavone B induced cell death via apoptosis (characterized by the appearance of nuclear morphology) and increased the accumulation of the sub-G1 peak (portion of apoptotic annexin V positive cells). Treatment with cudraflavone B triggered the mitochondrial apoptotic pathway (indicated by induction of the proapoptotic protein p53 and the p21 and p27 effector proteins), downregulation of cell cycle regulatory proteins (e.g., p-Rb, changing Bax/Bcl-2 ratios, cytochrome-c release), and caspase-3 activation. Cudraflavone B time-dependently activated NF-?B, the MAP kinases p38, and ERK, and induced the expression of SIRT1. SIRT1 activator, resveratrol, dose-dependently attenuated the growth-inhibitory and apoptosis-inducing effect of cudraflavone B and blocked cudraflavone B-induced regulatory protein expressions in the mitochondrial pathway such as p53, p21, p27, Bax, caspase-3, and cytochrome-c. Conversely, treatment with SIRT1 inhibitor sirtinol caused opposite effects. These results demonstrate for the first time that the molecular mechanism underlying the antitumor effect in oral squamous cell carcinoma cells is related to the activation of MAPK/and NF-?B as well as of the SIRT1 pathway. Therefore, cudraflavone B may be a lead for the development of a potential candidate for human oral squamous cell carcinoma cells. PMID:23881456

Lee, Hwa-Jeong; Auh, Q-Schick; Lee, Young-Man; Kang, Soo-Kyung; Chang, Seok-Woo; Lee, Dong-Sung; Kim, Youn-Chul; Kim, Eun-Cheol

2013-07-23

328

Apoptosis in animal models of virus-induced disease  

Microsoft Academic Search

Apoptosis is associated with virus-induced human diseases of the central nervous system, heart and liver, and causes substantial morbidity and mortality. Although virus-induced apoptosis is well characterized in individual cells in cell culture, virus-induced apoptosis in vivo and the role of apoptosis in virus-induced disease is not well established. This Review focuses on animal models of virus-induced diseases of the

Kenneth L. Tyler; Penny Clarke

2009-01-01

329

Oxygen Stress: A Regulator of Apoptosis in Yeast  

Microsoft Academic Search

Oxygen radicals are important components of metazoan apoptosis. We have found that apoptosis can be induced in the yeast Saccharomyces cerevisiae by depletion of glutathione or by low external doses of H 2 O 2 . Cycloheximide prevents apoptotic death reveal- ing active participation of the cell. Yeast can also be triggered into apoptosis by a mutation in CDC48 or

Frank Madeo; Eleonore Fröhlich; Martin Ligr; Martin Grey; Stephan J. Sigrist; Dieter H. Wolf; Kai-Uwe Fröhlich

1999-01-01

330

EXAMINING THE CELLULAR PATHWAYS INVOLVED IN INFLUENZA VIRUS INDUCED APOPTOSIS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Apoptosis is essential in many physiological processes including wound healing and development of the immune response. Apoptosis also plays an important role in the pathogenesis of many infectious diseases including those caused by viruses. Influenza viruses induce apoptosis in cells that are permis...

331

Apoptosis induced by ischemia and reperfusion in experimental lung transplantation  

Microsoft Academic Search

Background. Apoptosis is a distinct form of single-cell death in response to injury. Time course of apoptosis in lung parenchymal cells during posttransplant reperfusion and the influence of oxygen content during preservation on apoptosis of parenchymal cells are studied.Methods. Orthotopic syngenic single left lung transplantation was performed in male Fischer (F344) rats after 18 hours of cold ischemia (n =

Uz Stammberger; Ariana Gaspert; Sven Hillinger; Peter Vogt; Bernhard Odermatt; Walter Weder; Ralph A Schmid

2000-01-01

332

Apoptosis Regulators and Responses in Human Melanocytic and Keratinocytic Cells  

Microsoft Academic Search

Apoptosis in keratinocytes is required for epidermal turnover, stratum corneum formation, and removal of ultraviolet-damaged premalignant cells. Its role in melanocyte homeostasis and transformation, on the other hand, has not been defined, although apoptosis resistance is a commonly recognized feature of melanoma. We examined the expression of apoptosis regulators in melanocytes, keratinocytes, melanoma, and HaCat cells. Melanocytic cells expressed relatively

Anneli R Bowen; Adrianne N Hanks; Sarah M Allen; April Alexander; Miyoung J Diedrich; Douglas Grossman

2003-01-01

333

Trolox inhibits apoptosis in irradiated MOLT4 lymphocytes  

Microsoft Academic Search

MOLT-4 cells, a human lymphocytic leukemia line, undergo apoptosis in response to a variety of stimuli, including exposure to ionizing radiation. Very little is known of the molecular mechanisms by which radiation induces apoptosis. Morphology changes and chromatin cleavage at in- ternucleosomal sites accompany apoptosis in these cells. We found that trolox, a water-soluble deriva- tive of vitamin E that

JOHN F. KALINICH; NARAYANI RAMAKRISHNAN

334

Gliotoxin-mediated apoptosis of activated human hepatic stellate cells  

Microsoft Academic Search

Background: Activated hepatic stellate cells (HSCs) play a central role in liver fibrogenesis, and apoptosis of activated HSCs might be essential to clear HSCs from injured liver. Gliotoxin induces apoptosis of activated human and rat HSCs by an unknown mechanism.Aim: This study investigated the role of reactive oxygen species (ROS) and membrane permeability transition (MPT) in gliotoxin-induced apoptosis of activated

Young-Oh Kweon; Yong-Han Paik; Bernd Schnabl; Ting Qian; John J Lemasters; David A Brenner

2003-01-01

335

[Apoptosis, its mechanisms and medical significance. II. Disorders of apoptosis regulation and their relation to the development of diseases].  

PubMed

Study of apoptosis seems to be relevant to clinical medicine nowadays. Dysregulation of apoptosis is under the certain circumstances the cause of various pathological processes in organism. The numerous methods to analyse apoptosis are now well established. It is very likely that our better understanding of apoptosis could lead to improvement in diagnosis and treatment of diseases such as immunopathology, cancer, and others. PMID:11494885

Novosad, J; Kodydková, K; Krejsek, J

2001-06-01

336

Different effects of various phospholipids on Ki-Ras-, Ha-Ras-, and Rap1B-induced B-Raf activation.  

PubMed

We have recently purified a Ki-Ras- and Ha-Ras-dependent extracellular signal-regulated kinase kinase from bovine brain and identified it as B-Raf protein kinase complexed with 14-3-3 proteins (Yamamori, B., Kuroda, S., Shimizu, K., Fukui, K., Ohtsuka, T., and Takai, Y. (1995) J. Biol. Chem. 270, 11723-11726). Moreover, we found that Rap1B as well as Ki-Ras and Ha-Ras stimulate the B-Raf activity. Since B-Raf contains a cysteine-rich domain originally found in protein kinase C as a domain responsible for interaction with phosphatidylserine (PS) and diacylglycerol or 12-O-tetradecanoylphorbol-13-acetate, we have examined here the effect of these compounds on the Ki-Ras-, Ha-Ras-, and Rap1B-induced activation of bovine brain B-Raf. Bovine brain PS enhanced Ki-Ras-stimulated B-Raf activity. Phosphatidic acid was slightly active, but other phospholipids, such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol (PI), PI-4-monophosphate, PI-4,5-bisphosphate, and PI-3,4,5-trisphosphate, were inactive. However, none of the above phospholipids affected the Ha-Ras-stimulated B-Raf activity, whereas PI, PS, phosphatidylethanolamine, and phosphatidic acid inhibited the Rap1B-stimulated B-Raf activity. Phosphatidylcholine or PI-4-monophosphate did not show any effect on the Rap1B-stimulated B-Raf activity. Synthetic PS with two unsaturated fatty acids, such as 1,2-dioleoyl-PS or 1,2-dilinoleoyl-PS, showed the same effect toward the Ki-Ras- and Rap1B-stimulated B-Raf activities, but synthetic PS with two saturated fatty acids, such as 1, 2-distearoyl-PS, was inactive. 12-O-Tetradecanoylphorbol-13-acetate did not affect the stimulatory or inhibitory effect of PS on the Ki-Ras- and Rap1B-stimulated B-Raf activities, respectively. PS did not affect the Ki-Ras-, Ha-Ras-, or Rap1B-independent basal B-Raf activity or the mitogen-activated protein kinase kinase or extracellular signal-regulated kinase activity. These results indicate that various phospholipids differently affect Ki-Ras-, Ha-Ras, and Rap1B-induced B-Raf activation. PMID:8663012

Kuroda, S; Ohtsuka, T; Yamamori, B; Fukui, K; Shimizu, K; Takai, Y

1996-06-21

337

Apoptosis regulates notochord development in Xenopus  

PubMed Central

The notochord is the defining characteristic of the chordate embryo, and plays critical roles as a signaling center and as the primitive skeleton. In this study we show that early notochord development in Xenopus embryos is regulated by apoptosis. We find apoptotic cells in the notochord beginning at the neural groove stage and increasing in number as the embryo develops. These dying cells are distributed in an anterior to posterior pattern that is correlated with notochord extension through vacuolization. In axial mesoderm explants, inhibition of this apoptosis causes the length of the notochord to approximately double compared to controls. In embryos however, inhibition of apoptosis decreases the length of the notochord and it is severely kinked. This kinking also spreads from the anterior with developmental stage such that by the tadpole stage, the notochord lacks any recognizable structure, although notochord markers are expressed in a normal temporal pattern. Extension of the somites and neural plate mirror that of the notochord in these embryos, and the somites are severely disorganized. These data indicate that apoptosis is required for normal notochord development during the formation of the anterior-posterior axis, and its role in this process is discussed.

Malikova, Marina; Van Stry, Melanie

2009-01-01

338

Apoptosis and Epithelial Injury in the Lungs  

PubMed Central

Epithelial injury is a critical event in the development of acute lung injury, but the mechanisms that cause death of the alveolar epithelium are not completely understood. Epithelial death occurs by necrosis and apoptosis; more information is needed about the balance between these two types of cell death in the lungs. Direct epithelial necrosis probably occurs in response to bacterial exotoxins and overdistension of alveolar units by mechanical ventilation. Apoptosis is a regulated form of cell death that is mediated by membrane death receptors and direct mitochondrial injury. Apoptosis pathways are activated in the lungs of patients with acute lung injury, in part by activation of the membrane Fas death receptor by soluble Fas ligand (sFasL), which accumulates in biologically active form at the onset of lung injury. Accumulating evidence in humans and experimental models links sFasL and Fas pathway with lung epithelial injury and fibrosis. New strategies to inhibit Fas-mediated epithelial apoptosis need to be developed in order to develop new ways to preserve epithelial function in patients who develop acute lung injury.

Martin, Thomas R.; Hagimoto, Naoki; Nakamura, Morio; Matute-Bello, Gustavo

2005-01-01

339

Farnesol-Induced Apoptosis in Candida albicans? †  

PubMed Central

Farnesol, a precursor in the isoprenoid/sterol pathway, was recently identified as a quorum-sensing molecule produced by the fungal pathogen Candida albicans. Farnesol is involved in the inhibition of germination and biofilm formation by C. albicans and can be cytotoxic at certain concentrations. In addition, we have shown that farnesol can trigger apoptosis in mammalian cells via the classical apoptotic pathways. In order to elucidate the mechanism behind farnesol cytotoxicity in C. albicans, the response to farnesol was investigated, using proteomic analysis. Global protein expression profiles demonstrated significant changes in protein expression resulting from farnesol exposure. Among the downregulated proteins were those involved in metabolism, glycolysis, protein synthesis, and mitochondrial electron transport and the respiratory chain, whereas proteins involved in folding, protection against environmental and oxidative stress, actin cytoskeleton reorganization, and apoptosis were upregulated. Cellular changes that accompany apoptosis (regulated cell death) were further analyzed using fluorescent microscopy and gene expression analysis. The results indicated reactive oxygen species accumulation, mitochondrial degradation, and positive terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) in the farnesol-exposed cells concurrent with increased expression of antioxidant-encoding and drug response genes. More importantly, the results demonstrated farnesol-induced upregulation of the caspase gene MCA1 and the intracellular presence of activated caspases. In conclusion, this study demonstrated that farnesol promotes apoptosis in C. albicans through caspase activation, implying an important physiological role for farnesol in the fungal cell life cycle with important implications for adaptation and survival.

Shirtliff, Mark E.; Krom, Bastiaan P.; Meijering, Roelien A. M.; Peters, Brian M.; Zhu, Jingsong; Scheper, Mark A.; Harris, Megan L.; Jabra-Rizk, Mary Ann

2009-01-01

340

Biophotonic probing of macromolecular transformations during apoptosis.  

PubMed

We introduce here multiplex nonlinear optical imaging as a powerful tool for studying the molecular organization and its transformation in cellular processes, with the specific example of apoptosis. Apoptosis is a process of self-initiated cell death, critically important for physiological regulation and elimination of genetic disorders. Nonlinear optical microscopy, combining the coherent anti-Stokes Raman scattering (CARS) microscopy and two-photon excited fluorescence (TPEF), has been used for analysis of spatial distribution of major types of biomolecules: proteins, lipids, and nucleic acids in the cells while monitoring their changes during apoptosis. CARS imaging revealed that in the nuclei of proliferating cells, the proteins are distributed nearly uniformly, with local accumulations in several nuclear structures. We have found that this distribution is abruptly disrupted at the onset of apoptosis and is transformed to a progressively irregular pattern. Fluorescence recovery after photobleaching (FRAP) studies indicate that pronounced aggregation of proteins in the nucleoplasm of apoptotic cells coincides with a gradual reduction in their mobility. PMID:20615987

Pliss, Artem; Kuzmin, Andrey N; Kachynski, Aliaksandr V; Prasad, Paras N

2010-07-06

341

Biophotonic probing of macromolecular transformations during apoptosis  

PubMed Central

We introduce here multiplex nonlinear optical imaging as a powerful tool for studying the molecular organization and its transformation in cellular processes, with the specific example of apoptosis. Apoptosis is a process of self-initiated cell death, critically important for physiological regulation and elimination of genetic disorders. Nonlinear optical microscopy, combining the coherent anti-Stokes Raman scattering (CARS) microscopy and two-photon excited fluorescence (TPEF), has been used for analysis of spatial distribution of major types of biomolecules: proteins, lipids, and nucleic acids in the cells while monitoring their changes during apoptosis. CARS imaging revealed that in the nuclei of proliferating cells, the proteins are distributed nearly uniformly, with local accumulations in several nuclear structures. We have found that this distribution is abruptly disrupted at the onset of apoptosis and is transformed to a progressively irregular pattern. Fluorescence recovery after photobleaching (FRAP) studies indicate that pronounced aggregation of proteins in the nucleoplasm of apoptotic cells coincides with a gradual reduction in their mobility.

Pliss, Artem; Kuzmin, Andrey N.; Kachynski, Aliaksandr V.; Prasad, Paras N.

2010-01-01

342

Apoptosis: Letting Slip The Dogs Of War  

Microsoft Academic Search

Recent studies have shown that, during cell death, the protein Omi is released from the mitochondrial intermembrane space into the cytosol, where it augments caspase-dependent apoptosis by blocking inhibitors and may induce caspase-independent cell death via its serine protease activity.

Beni B Wolf; Douglas R Green

2002-01-01

343

The modulation of apoptosis by oncogenic viruses  

PubMed Central

Transforming viruses can change a normal cell into a cancer cell during their normal life cycle. Persistent infections with these viruses have been recognized to cause some types of cancer. These viruses have been implicated in the modulation of various biological processes, such as proliferation, differentiation and apoptosis. The study of infections caused by oncogenic viruses had helped in our understanding of several mechanisms that regulate cell growth, as well as the molecular alterations leading to cancer. Therefore, transforming viruses provide models of study that have enabled the advances in cancer research. Viruses with transforming abilities, include different members of the Human Papillomavirus (HPV) family, Hepatitis C virus (HCV), Human T-cell Leukemia virus (HTLV-1), Epstein Barr virus (EBV) and Kaposi’s Sarcoma Herpesvirus (KSHV). Apoptosis, or programmed cell death, is a tightly regulated process that plays an important role in development and homeostasis. Additionally, it functions as an antiviral defense mechanism. The deregulation of apoptosis has been implicated in the etiology of diverse diseases, including cancer. Oncogenic viruses employ different mechanisms to inhibit the apoptotic process, allowing the propagation of infected and damaged cells. During this process, some viral proteins are able to evade the immune system, while others can directly interact with the caspases involved in apoptotic signaling. In some instances, viral proteins can also promote apoptosis, which may be necessary for an accurate regulation of the initial stages of infection.

2013-01-01

344

The modulation of apoptosis by oncogenic viruses.  

PubMed

Transforming viruses can change a normal cell into a cancer cell during their normal life cycle. Persistent infections with these viruses have been recognized to cause some types of cancer. These viruses have been implicated in the modulation of various biological processes, such as proliferation, differentiation and apoptosis. The study of infections caused by oncogenic viruses had helped in our understanding of several mechanisms that regulate cell growth, as well as the molecular alterations leading to cancer. Therefore, transforming viruses provide models of study that have enabled the advances in cancer research. Viruses with transforming abilities, include different members of the Human Papillomavirus (HPV) family, Hepatitis C virus (HCV), Human T-cell Leukemia virus (HTLV-1), Epstein Barr virus (EBV) and Kaposi's Sarcoma Herpesvirus (KSHV).Apoptosis, or programmed cell death, is a tightly regulated process that plays an important role in development and homeostasis. Additionally, it functions as an antiviral defense mechanism. The deregulation of apoptosis has been implicated in the etiology of diverse diseases, including cancer. Oncogenic viruses employ different mechanisms to inhibit the apoptotic process, allowing the propagation of infected and damaged cells. During this process, some viral proteins are able to evade the immune system, while others can directly interact with the caspases involved in apoptotic signaling. In some instances, viral proteins can also promote apoptosis, which may be necessary for an accurate regulation of the initial stages of infection. PMID:23741982

Fuentes-González, Alma Mariana; Contreras-Paredes, Adriana; Manzo-Merino, Joaquín; Lizano, Marcela

2013-06-06

345

Liposomal Sphingolipids to Target Breast Adenocarcinoma Apoptosis.  

National Technical Information Service (NTIS)

We have observed that certain sphingolipids (e.g., dimethyl- sphingosine: DMSP) induce apoptosis in vitro in tumor cells despite the over- expression of HER-2/neu and other resistance mechanisms relevant to breast cancer. In these studies, we translated f...

J. Klostergaard

2003-01-01

346

Calcium Signalling and the Regulation of Apoptosis  

Microsoft Academic Search

Apoptotic cell death is characterized by cell shrinkage, chromatin condensation and fragmentation, formation of apoptotic bodies and phagocytosis (Kerr et al., 1972). At the molecular level, activation of a family of cysteine proteases, caspases, related to interleukin-1?-converting enzyme is believed to be a crucial event in apoptosis. This is associated with the proteolysis of nuclear and cytoskeletal proteins, cell shrinkage,

M. I. Pörn-Ares; M. P. S. Ares; S. Orrenius

1998-01-01

347

Death penalty for keratinocytes: apoptosis versus cornification  

Microsoft Academic Search

Homeostasis implies a balance between cell growth and cell death. This balance is essential for the development and maintenance of multicellular organisms. Homeostasis is controlled by several mechanisms including apoptosis, a process by which cells condemned to death are completely eliminated. However, in some cases, total destruction and removal of dead cells is not desirable, as when they fulfil a

S Lippens; G Denecker; P Ovaere; P Vandenabeele; W Declercq

2005-01-01

348

Hormonal Regulation of Apoptosis An Ovarian Perspective  

Microsoft Academic Search

Using the ovary as a model system for studying the hormonal regulation of apoptosis, recent studies have revealed that the survival of growing follicles is under the regulation of a complex array of hormones through endocrine, paracrine, autocrine, or juxtacrine mechanism in a development-dependent manner. More effort is needed, however, to identify tissue-specific factors required for the survival of ovarian

Sheau Yu Hsu; Aaron J. W Hsueh

1997-01-01

349

Increased placental apoptosis in intrauterine growth restriction  

Microsoft Academic Search

OBJECTIVES: Our purpose was to investigate a possible role for apoptosis in the pathophysiologic mechanisms of intrauterine growth restriction. STUDY DESIGN: Placental samples were obtained from 43 uncomplicated third-trimester pregnancies and from 26 pregnancies complicated by intrauterine growth restriction. The definition used to identify cases of intrauterine growth restriction depended on three criteria: clinical evidence of suboptimal growth, ultrasonographic evidence

Stephen C. Smith; Philip N. Baker; E. Malcolm Symonds

1997-01-01

350

Induction of Apoptosis by Cancer Chemotherapy  

Microsoft Academic Search

Studies performed over the past five years have demonstrated that there are two major cell-intrinsic pathways for inducing apoptosis, one that begins with ligation of cell surface death receptors and another that involves mitochondrial release of cytochrome c. Several reports have suggested that anticancer drugs kill susceptible cells by inducing expression of death receptor ligands, especially Fas ligand (FasL). Other

Scott H. Kaufmann; William C. Earnshaw

2000-01-01

351

Calcium and apoptosis: facts and hypotheses  

Microsoft Academic Search

Although longstanding experimental evidence has associated alterations of calcium homeostasis to cell death, only in the past few years the role of calcium in the signaling of apoptosis has been extensively investigated. In this review, we will summarize the current knowledge, focusing on (i) the effect of the proteins of the Bcl-2 family on ER Ca2+ levels, (ii) the action

Rosario Rizzuto; Paolo Pinton; Davide Ferrari; Mounia Chami; György Szabadkai; Paulo J Magalhães; Francesco Di Virgilio; Tullio Pozzan

2003-01-01

352

Role of Apoptosis in Duchenne's Muscular Dystrophy  

Microsoft Academic Search

We investigated the presence of apoptosis in muscle tissues from 24 patients (average age 5.44 ± 1.81 years) with Duchenne's muscular dystrophy by in situ tailing of nuclear fragmentation. Muscle tissue from 4 children without histologic evidence of myopathy served as normal controls. Muscle fibers positive for nuclear DNA fragmentation were determined quantitatively by counting an area of at least

Ayse Serdaroglu; Kivilcim Gücüyener; Sevim Erdem; Gül?en Köse; Ersin Tan; Çetin Okuyaz

2002-01-01

353

Calpain activator dibucaine induces platelet apoptosis.  

PubMed

Calcium-dependent calpains are a family of cysteine proteases that have been demonstrated to play key roles in both platelet glycoprotein Ib? shedding and platelet activation and altered calpain activity is associated with thrombotic thrombocytopenic purpura. Calpain activators induce apoptosis in several types of nucleated cells. However, it is not clear whether calpain activators induce platelet apoptosis. Here we show that the calpain activator dibucaine induced several platelet apoptotic events including depolarization of the mitochondrial inner transmembrane potential, up-regulation of Bax and Bak, down-regulation of Bcl-2 and Bcl-X(L), caspase-3 activation and phosphatidylserine exposure. Platelet apoptosis elicited by dibucaine was not affected by the broad spectrum metalloproteinase inhibitor GM6001. Furthermore, dibucaine did not induce platelet activation as detected by P-selectin expression and PAC-1 binding. However, platelet aggregation induced by ristocetin or ?-thrombin, platelet adhesion and spreading on von Willebrand factor were significantly inhibited in platelets treated with dibucaine. Taken together, these data indicate that dibucaine induces platelet apoptosis and platelet dysfunction. PMID:21731431

Zhang, Weilin; Liu, Jun; Sun, Ruichen; Zhao, Lili; Du, Juan; Ruan, Changgeng; Dai, Kesheng

2011-03-25

354

Spontaneous and inducible apoptosis in oesophageal adenocarcinoma  

PubMed Central

The use of neoadjuvant chemoradiotherapy prior to surgery in the treatment of oesophageal adenocarcinoma has increased in recent years, and up to 25% of patients will have a complete pathological response to the neoadjuvant therapy. Many patients will not respond, however, and the knowledge of molecular factors predicting response or resistance to chemoradiotherapy is required to enhance treatment results. An understanding of apoptosis and cell proliferation may be relevant and this study focused on apoptotic indices and cell-cycle related (Ki-67, p53 and bcl-2) protein expression in a cohort of 42 patients with primary oesophageal adenocarcinoma. We documented that apoptosis occurs among viable (proliferating) tumour cells in all adenocarcinoma cases examined in this study. Pre-operative chemoradiotherapy significantly increased apoptosis and significantly decreased cell proliferation (estimated by Ki-67 expression). Immunohistochemically detected p53 and bcl-2 gene products had no regulatory role in the apoptotic process. The cumulative expression of p53 protein is significantly associated with increasing proliferation activity. Evaluation of apoptosis in pre-treatment specimens may have potential utility in predicting the efficacy of treatment. Assessment of the tumours proliferation activity by Ki-67 expression might identify patients who are at risk of developing metastastic disease. © 2001 Cancer Research Campaign http://www.bjcancer.com

Raouf, A; Evoy, D; Carton, E; Mulligan, E; Griffin, M; Sweeney, E; Reynolds, J V

2001-01-01

355

Apoptosis-based therapies and drug targets  

Microsoft Academic Search

The pathogenesis of many diseases is most closely connected with aberrantly regulated apoptotic cell death. The past 15 years have witnessed an explosion in the basic knowledge of mechanisms that regulate apoptosis and the mediators that either trigger or inhibit cell death. Consequently, great interest has emerged in devising therapeutic strategies for modulating the key molecules of life-and-death decisions. Numerous

U Fischer; K Schulze-Osthoff

2005-01-01

356

Stimulatory effect of curcumin on osteoclast apoptosis  

Microsoft Academic Search

Curcumin is a potent inhibitor of the transcriptional factors activator protein-1 and nuclear factor-?B. Since transcriptional factors may play a functional role in the survival of osteoclasts, it was of interest to us to examine the effect of curcumin on osteoclast apoptosis. We observed that curcumin is a potent stimulator of this process in rabbit osteoclasts, as evidenced by morphological

Ken Ozaki; Yasuhiro Kawata; Shigeru Amano; Shigemasa Hanazawa

2000-01-01

357

THE ROLE OF APOPTOSIS IN NEUROTOXICOLOGY  

EPA Science Inventory

Apoptosis, a form of programmed cell death, occurs in the nervous system throughout development, but with a preponderance of cell death occurring during the prenatal and perinatal periods. Aberrant periods of increased or decreased cell death, induced by toxicants in air, water,...

358

Apoptosis: A Role in Skin Aging?  

Microsoft Academic Search

Prevailing theories view aging as an outcome of both programmed and stochastic events that occur over the lifetime of the individual. In this context, aging can be defined as a progressive decline in homeostasis and a period characterized by the inability of the organism to respond adaptively to stress. Apoptosis thus stands out as a potential key cellular process that

Anne R Haake; Inna Roublevskaia; Molly Cooklis

1998-01-01

359

TRAIL Induced Apoptosis - A Prostate Cancer Therapy.  

National Technical Information Service (NTIS)

Five of six prostate cancer cell lines undergo apoptosis when incubated with% TRAIL. Cell viability curves of six prostate cancer cell lines using varying amounts of TRAIL protein were completed. Prostate cancer cell lines Alva 31, PC-3 and DU 145 are hig...

X. Lu D. M. Rodman

2000-01-01

360

Stimulation of platelet apoptosis by balhimycin.  

PubMed

Glycopeptides, such as vancomycin, are powerful antibiotics against methicillin-resistant Staphylococcus aureus. Balhimycin, a glycopeptide antibiotic isolated from Amycolatopsis balhimycina, is similarly effective as vancomycin. Side effects of vancomycin include triggering of platelet apoptosis, which is characterized by cell shrinkage and by cell membrane scrambling with phosphatidylserine exposure at the cell surface. Stimulation of apoptosis may involve increase of cytosolic Ca(2+) activity, ceramide formation, mitochondrial depolarization and/or caspase activation. An effect of balhimycin on apoptosis has, however, never been reported. The present study thus tested whether balhimycin triggers platelet apoptosis. Human blood platelets were treated with balhimycin and cell volume was estimated from forward scatter, phosphatidylserine exposure from annexin V-binding, cytosolic Ca(2+) activity from fluo-3AM fluorescence, ceramide formation utilizing antibodies, mitochondrial potential from DiOC6 fluorescence, and caspase-3 activity utilizing antibodies. As a result, a 30 min exposure to balhimycin significantly decreased cell volume (?1 ?g/ml), triggered annexin V binding (?1 ?g/ml), increased cytosolic Ca(2+) activity (?1 ?g/ml), stimulated ceramide formation (?10 ?g/ml), depolarized mitochondria (?1 ?g/ml) and activated caspase-3 (?1 ?g/ml). Cell membrane scrambling and caspase-3 activation were virtually abrogated by removal of extracellular Ca(2+). Cell membrane scrambling was not significantly blunted by pancaspase inhibition with zVAD-FMK (1?M). In conclusion, balhimycin triggers cell membrane scrambling of platelets, an effect dependent on Ca(2+), but not on activation of caspases. PMID:23399563

Towhid, Syeda T; Tolios, Alexander; Münzer, Patrick; Schmidt, Eva-Maria; Borst, Oliver; Gawaz, Meinrad; Stegmann, Evi; Lang, Florian

2013-02-09

361

Iodination of Annexin V for Imaging Apoptosis  

Microsoft Academic Search

Our goal in this investigation was to develop a method for iodinating annexin V that would be suitable for the in vivo detection of apoptosis. Methods: Annexin V was iodinated with 125I using 2 different techniques: direct iodination with IODO- BEADS, resulting in the iodination of tyrosine residues; and use of the Bolton-Hunter reagent, which binds to lysine. The active

James Russell; Joseph A. O'Donoghue; Ron Finn; Jacek Koziorowski; Shutian Ruan; John L. Humm; C. Clifton Ling

362

Alymphoplasia ( aly )-type Nuclear Factor k B-inducing Kinase (NIK) Causes Defects in Secondary Lymphoid Tissue Chemokine Receptor Signaling and Homing of Peritoneal Cells to the Gut-associated Lymphatic Tissue System  

Microsoft Academic Search

Alymphoplasia ( aly ) mice, which carry a point mutation in the nuclear factor k B-inducing ki- nase (NIK) gene, are characterized by the systemic absence of lymph nodes and Peyer's patches, disorganized splenic and thymic architectures, and immunodeficiency. Another unique feature of aly\\/aly mice is that their peritoneal cavity contains more B1 cells than normal and aly\\/ 1 mice.

Sidonia Fagarasan; Reiko Shinkura; Tadashi Kamata; Fumiaki Nogaki; Koichi Ikuta; Kei Tashiro; Tasuku Honjo

363

Expression of apoptosis-related oncoproteins and modulation of apoptosis by caffeine in human leukemic cells  

Microsoft Academic Search

We investigated the modulation of radio- and chemoresistance by caffeine and mechanisms of resistance in human leukemic cell lines and mononuclear cells from 18 leukemic patients. Caffeine synergistically potentiated cytotoxicity and apoptosis induced by ionizing radiation or carboplatin (CPt), but attenuated induction of apoptosis by daunorubicin (DNR) in KG-1a cells. Since caffeine released irradiated as well as DNR-treated KG-1a cells

T. Efferth; U. Fabry; P. Glatte; R. Osieka

1995-01-01

364

Curcumin enhances the apoptosis-inducing potential of TRAIL in prostate cancer cells: molecular mechanisms of apoptosis, migration and angiogenesis  

Microsoft Academic Search

BACKGROUND: We have recently shown that curcumin (a diferuloylmethane) inhibits growth and induces apoptosis, and also demonstrated that TRAIL induces apoptosis by binding to specific cell surface death receptors in prostate cancer cells. The objectives of this paper were to investigate the molecular mechanisms by which curcumin enhanced the apoptosis-inducing potential of TRAIL in prostate cancer cells. RESULTS: Curcumin enhanced

Sharmila Shankar; Qinghe Chen; Krishna Sarva; Imtiaz Siddiqui; Rakesh K Srivastava

2007-01-01

365

[Delayed apoptosis and its regulation in astrocytes].  

PubMed

Astrocytes, the most abundant glial cell type in the brain, are considered to have physiological and pathological roles in neuronal activities. We found that reperfusion of cultured astrocytes after Ca2+ depletion causes Ca2+ overload followed by delayed cell death and the Na(+)-Ca2+ exchanger in the reverse mode is responsible for this Ca(2+)-mediated cell injury (Ca2+ paradox injury). The Ca2+ paradox injury of cultured astrocytes is considered to be an in vitro model of ischemia/reperfusion injury, since a similar paradoxical change in extracellular Ca2+ concentration is reported in ischemic brain tissue. This review summarizes the mechanisms underlying the Ca(2+)-mediated injury of astrocytes and the protective effects of drugs against Ca2+ reperfusion injury. This study shows that Ca2+ reperfusion injury of astrocytes is accompanied by apoptosis as evidenced by DNA fragmentation and nuclear condensation. Calpain, reactive oxygen species, calcineurin, caspase-3, and NF-kappa B are involved in Ca2+ reperfusion-induced delayed apoptosis of astrocytes. Several drugs including CV-2619, T-588 and ibudilast protect astrocytes against the delayed apoptosis. CV-2619 prevents astrocytes from the delayed apoptosis by production of nerve growth factor, resulting in an activation of mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) and phosphatidylinositol-3 (PI3) kinase signal pathways. The protective effect of T-588 is mainly mediated by an activation of MAP/ERK signal cascade. Moreover, ibudilast prevents the Ca2+ reperfusion-induced delayed apoptosis of astrocytes via cyclic GMP signaling pathway. Further studies in this system will contribute to the development of new drugs that attenuate ischemia/reperfusion injury via modulation of astrocytes. PMID:11558150

Takuma, K

2001-09-01

366

Prevention of apoptosis reperfusion renal injury by calcium channel blockers.  

PubMed

Apoptosis has been shown in the literature to be the form of cell death occurring in renal tubular epithelial cells during the reperfusion phase after brief periods of renal ischaemia. In the present study apoptosis was examined in the rat kidney in the first 24 hours after 30 min ischaemia and apoptosis was influenced by administration of the Ca channel blockers Verapamil, Bepridil, Nifedipin and Sensit. Apoptosis was observed in the renal tubular cells two hours after the start of reperfusion and reached in maximum at hour 6. All above mentioned Ca channel blockers decreased the occurrence and degree of apoptosis. PMID:10334460

Toronyi, E; Hamar, J; Perner, F; Szende, B

1999-05-01

367

Apoptosis in animal models of virus-induced disease  

PubMed Central

Apoptosis is associated with virus-induced human diseases of the central nervous system, heart and liver, and causes substantial morbidity and mortality. Although virus-induced apoptosis is well characterized in individual cells in cell culture, virus-induced apoptosis in vivo and the role of apoptosis in virus-induced disease is not well established. This Review focuses on animal models of virus-induced diseases of the central nervous system, heart and liver that provide insights into the role of apoptosis in pathogenesis, the pathways involved and the potential therapeutic implications.

Clarke, Penny; Tyler, Kenneth L.

2009-01-01

368

Cell-Intrinsic Role for NF-kappa B-Inducing Kinase in Peripheral Maintenance but Not Thymic Development of Foxp3(+) Regulatory T Cells in Mice.  

PubMed

NF-?B inducing kinase (NIK, MAP3K14) is a key signaling molecule in non-canonical NF-?B activation, and NIK deficient mice have been instrumental in deciphering the immunologic role of this pathway. Global ablation of NIK prevents lymph node development, impairs thymic stromal development, and drastically reduces B cells. Despite altered thymic selection, T cell numbers are near normal in NIK deficient mice. The exception is CD4(+) regulatory T cells (Tregs), which are reduced in the thymus and periphery. Defects in thymic stroma are known to contribute to impaired Treg generation, but whether NIK also plays a cell intrinsic role in Tregs is unknown. Here, we compared intact mice with single and mixed BM chimeric mice to assess the intrinsic role of NIK in Treg generation and maintenance. We found that while NIK expression in stromal cells suffices for normal thymic Treg development, NIK is required cell-intrinsically to maintain peripheral Tregs. In addition, we unexpectedly discovered a cell-intrinsic role for NIK in memory phenotype conventional T cells that is masked in intact mice, but revealed in BM chimeras. These results demonstrate a novel role for NIK in peripheral regulatory and memory phenotype T cell homeostasis. PMID:24073289

Murray, Susan E

2013-09-20

369

Shiga toxin (Stx)1B and Stx2B induce von Willebrand factor secretion from human umbilical vein endothelial cells through different signaling pathways  

PubMed Central

Diarrhea-associated hemolytic uremic syndrome (D+HUS) is caused by the ingestion of Escherichia coli that produce Shiga toxin (Stx), which is composed of a cytotoxic A subunit and pentameric B subunits that bind globotriaosylceramide on susceptible cells. Stx occurs in 2 types, Stx1 and Stx2. B subunits of either type stimulate von Willebrand factor (VWF) secretion from human umbilical vein endothelial cells (HUVECs), and Stx2B can cause thrombotic microangiopathy in Adamts13?/? mice. We have now determined that Stx1B and Stx2B activate different signaling pathways in HUVECs. VWF secretion induced by Stx1B is associated with a transient rise in intracellular Ca2+ level that is blocked by chelation with 1,2-bis(2-aminophenoxy)ethane-N,N,N?,N?-tetraacetic acid-acetoxymethyl ester, removal of extracellular Ca2+, the phospholipase C inhibitor U73122, the protein kinase inhibitor staurosporine, or small interfering RNA knockdown of protein kinase C?. In contrast, Stx2B-induced VWF secretion is associated with activation of protein kinase A (PKA) and is blocked by the PKA inhibitor H89 or small interfering RNA knockdown of PKA. Stx2B does not increase cAMP levels and may activate PKA by a cAMP-independent mechanism. The activation of distinct signaling pathways may be relevant to understanding why E coli that express Stx2 are more likely to cause D+HUS than are E coli expressing only Stx1.

Liu, Fang; Huang, Jing

2011-01-01

370

Cell-Intrinsic Role for NF-kappa B-Inducing Kinase in Peripheral Maintenance but Not Thymic Development of Foxp3+ Regulatory T Cells in Mice  

PubMed Central

NF-?B inducing kinase (NIK, MAP3K14) is a key signaling molecule in non-canonical NF-?B activation, and NIK deficient mice have been instrumental in deciphering the immunologic role of this pathway. Global ablation of NIK prevents lymph node development, impairs thymic stromal development, and drastically reduces B cells. Despite altered thymic selection, T cell numbers are near normal in NIK deficient mice. The exception is CD4+ regulatory T cells (Tregs), which are reduced in the thymus and periphery. Defects in thymic stroma are known to contribute to impaired Treg generation, but whether NIK also plays a cell intrinsic role in Tregs is unknown. Here, we compared intact mice with single and mixed BM chimeric mice to assess the intrinsic role of NIK in Treg generation and maintenance. We found that while NIK expression in stromal cells suffices for normal thymic Treg development, NIK is required cell-intrinsically to maintain peripheral Tregs. In addition, we unexpectedly discovered a cell-intrinsic role for NIK in memory phenotype conventional T cells that is masked in intact mice, but revealed in BM chimeras. These results demonstrate a novel role for NIK in peripheral regulatory and memory phenotype T cell homeostasis.

Murray, Susan E.

2013-01-01

371

A Virion-Associated Protein Kinase Induces Apoptosis?  

PubMed Central

Apoptosis and inhibition of host gene expression are often associated with virus infections. Many viral polypeptides modulate apoptosis by direct interaction with highly conserved apoptotic pathways. Some viruses induce apoptosis during late stages of the infection cycle, while others inhibit apoptosis to facilitate replication or maintain persistent infection. In previous work, we showed that Chilo iridescent virus (CIV) or CIV virion protein extract induces apoptosis in spruce budworm and cotton boll weevil cell cultures. Here, we characterize the product of a CIV gene (iridovirus serine/threonine kinase; istk) with signature sequences for S/T kinase and ATP binding. ISTK appears to belong to the superfamily, vaccinia-related kinases (VRKs). The istk gene was expressed in Pichia pastoris vectors. Purified ISTK (48 kDa) exhibited S/T kinase activity. Treatment with ISTK induced apoptosis in budworm cells. A 35-kDa cleavage product of ISTK retaining key signature sequences was identified during purification. Pichia-expressed 35-kDa polypeptide, designated iridoptin, induced apoptosis and inhibition of host protein synthesis in budworm and boll weevil cells. A mutation in the ATP-binding site eliminated both kinase and apoptosis activity of iridoptin, suggesting that kinase activity is essential for induction of apoptosis. Analysis with custom antibody confirmed that ISTK is a structural component of CIV particles. This is the first demonstration of a viral kinase inducing apoptosis in any virus-host system and the first identification of a factor inducing apoptosis or host protein shutoff for the family Iridoviridae.

Chitnis, Nilesh S.; Paul, Eric R.; Lawrence, Paulraj K.; Henderson, Curtis W.; Ganapathy, Saranya; Taylor, Patrick V.; Virdi, Kamaldeep S.; D'Costa, Susan M.; May, Ashley R.; Bilimoria, Shan L.

2011-01-01

372

emm1/Sequence Type 28 Strains of Group A Streptococci That Express covR at Early Stationary Phase Are Associated with Increased Growth and Earlier SpeB Secretion?  

PubMed Central

Streptococcus pyogenes (group A streptococcus [GAS]) is a versatile human pathogen, and emm1/sequence type 28 (ST28) is the most frequently isolated type from GAS infections. The emm1/ST28 strain is associated with necrotizing fasciitis and streptococcal toxic shock syndrome. Growth-phase regulation is one of the important regulatory mechanisms in GAS, which controls gene expression at restricted phases of growth. CovRS, a two-component regulatory system, is considered the regulator of streptococcal pyrogenic exotoxin B (SpeB) and is thought to be activated in the exponential phase of growth. In the present study, Northern hybridization analysis showed that 52% of the analyzed GAS strains expressed covR at the exponential phase, but 48% of the strains expressed covR at the early stationary phase of growth. Strains transcribing covR at the early stationary phase showed better growth and earlier SpeB expression than the other group of strains. Multilocus sequence typing and pulsed-field gel electrophoresis analysis showed only emm1/ST28 strains (which comprise a clonal cluster) were expressing covR at the early stationary phase of growth, indicating that emm1/ST28 strains have special characteristics which may be related to their worldwide distribution.

Chiang-Ni, Chuan; Zheng, Po-Xing; Ho, Yueh-Ren; Wu, Hsiu-Mei; Chuang, Woei-Jer; Lin, Yee-Shin; Lin, Ming-T.; Liu, Ching-Chuan; Wu, Jiunn-Jong

2009-01-01

373

Evaluation of the solid-phase extraction (SPE) cartridge method in combination with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) for the analysis of different VOCs in liquid matrices in varying pH conditions.  

PubMed

In this study, the solid-phase extraction (SPE) method combined with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method is evaluated for the analysis of liquid-phase volatile organic compounds (LVOCs). Calibration experiments were performed on a number of polar and nonpolar LVOCs (including aromatic compounds, ester, ketones, and alcohol) as a function of solution pH. If the relative sensitivity of the SPE-TD-GC-MS method is compared between different VOCs across a wide range of pH (1, 4, 7, 10, and 13), optimum sensitivities for most VOCs are derived at the neutral pH. However, there were some exceptions to the general trend with the maximum sensitivity occurring either at a moderately basic pH (methyl isobutyl ketone and butyl acetate) or extremely acidic conditions (isobutyl alcohol). It was also noticed that the relative ordering of sensitivity was changed, as the pH conditions of the solution vary. The use of internal standard (IS: chlorobenzene) resulted in a notable improvement in both relative sensitivity and reproducibility for most compounds. PMID:22865756

Pandey, Sudhir Kumar; Kim, Ki-Hyun

2012-08-01

374

Delayed neutrophil apoptosis in bovine subclinical mastitis.  

PubMed

Bovine subclinical mastitis can be defined as a moderated inflammatory disease characterized by a persistent accumulation of neutrophils in milk. As GMCSF-mediated delay of neutrophil apoptosis contributes to the accumulation of inflammatory cells at the site of inflammation in many human diseases, we sought to determine whether subclinical mastitis in cows is also associated with a GMCSF-dependent increase in milk-neutrophil survival. We first addressed the hypothesis that GMCSF delays bovine neutrophil apoptosis by activation of the signal transducer and activator of transcription (STAT) family members STAT3 and STAT5, which are critical regulators of the expression of various Bcl-2 family proteins. Granulocyte-macrophage colony-stimulating factor significantly delayed apoptosis of blood neutrophils obtained from healthy cows. In these cells, GMCSF activated STAT5, but not STAT3, and induced an increase in the mRNA of the antiapoptotic Bcl-2 member, Bcl-xL. Granulocyte-macrophage colony-stimulating factor-dependent STAT5 activation and up-regulation of Bcl-xL mRNA were blocked by the Jak inhibitor, AG-490. This inhibition was associated with abrogation of the prosurvival effect of GMCSF, demonstrating a key role for STAT5 in delayed neutrophil apoptosis. We further found that GMCSF expression was increased in milk cells from cows affected with subclinical mastitis. Neutrophils from these cows demonstrated a significant delay of apoptosis as compared with neutrophils obtained from healthy cows and were unresponsive to GMCSF. Active STAT5 complexes were detected in these neutrophils. Finally, in the presence of AG-490, apoptosis was induced and a time-dependent down-regulation of Bcl-xL mRNA was observed in milk neutrophils from mastitis-affected cows. These results indicate that neutrophil survival is enhanced in milk of subclinical mastitis-affected cows and suggest a role for a GMCSF-activated STAT5 signaling pathway in this phenomenon. This pathway could thus represent a target for the control of persistent accumulation of neutrophils in the bovine mammary gland. PMID:15545372

Boutet, P; Boulanger, D; Gillet, L; Vanderplasschen, A; Closset, R; Bureau, F; Lekeux, P

2004-12-01

375

Sustained adenosine exposure causes lung endothelial apoptosis: a possible contributor to cigarette smoke-induced endothelial apoptosis and lung injury.  

PubMed

Pulmonary endothelial cell (EC) apoptosis has been implicated in the pathogenesis of emphysema. Cigarette smoke (CS) causes lung EC apoptosis and emphysema. In this study, we show that CS exposure increased lung tissue adenosine levels in mice, an effect associated with increased lung EC apoptosis and the development of emphysema. Adenosine has a protective effect against apoptosis via adenosine receptor-mediated signaling. However, sustained elevated adenosine increases alveolar cell apoptosis in adenosine deaminase-deficient mice. We established an in vitro model of sustained adenosine exposure by incubating lung EC with adenosine in the presence of an adenosine deaminase inhibitor, deoxycoformicin. We demonstrated that sustained adenosine exposure caused lung EC apoptosis via nucleoside transporter-facilitated intracellular adenosine uptake, subsequent activation of p38 and JNK in mitochondria, and ultimately mitochondrial defects and activation of the mitochondria-mediated intrinsic pathway of apoptosis. Our results suggest that sustained elevated adenosine may contribute to CS-induced lung EC apoptosis and emphysema. Our data also reconcile the paradoxical effects of adenosine on apoptosis, demonstrating that prolonged exposure causes apoptosis via nucleoside transporter-mediated intracellular adenosine signaling, whereas acute exposure protects against apoptosis via activation of adenosine receptors. Inhibition of adenosine uptake may become a new therapeutic target in treatment of CS-induced lung diseases. PMID:23316066

Lu, Qing; Sakhatskyy, Pavlo; Newton, Julie; Shamirian, Paul; Hsiao, Vivian; Curren, Sean; Gabino Miranda, Gustavo Andres; Pedroza, Mesias; Blackburn, Michael R; Rounds, Sharon

2013-01-11

376

UV-B induced morphogenesis  

PubMed Central

Low levels of ultraviolet (UV)-radiation alter the morphology of plants. UV-B exposure can lead to shorter petioles and shorter, narrower and/or thicker leaf blades. The resulting decrease in leaf area has been associated with inhibitory UV-B effects on biomass accumulation. In Arabidopsis, UV-B effects on leaf area have variously been attributed to altered cell division, cell expansion or combinations of these two processes. A dedicated UV-B sensory system, crosstalk between flavonoids and auxins, endoreduplication and generic Stress Induced Morphogenic Responses (SIMR) have all been proposed to contribute to the UV-B phenotype. Here, we propose that UV-mediated morphogenesis, rather than being controlled by a single regulatory pathway, is controlled by a regulatory blur involving multiple compensatory molecular and physiological feedback interactions.

Jansen, Marcel A.K.; Coffey, Aoife M.; Prinsen, Els

2012-01-01

377

THE CONSEQUENCES OF APOPTOSIS IN AUTOIMMUNITY  

PubMed Central

The clearance of apoptotic cells is a highly regulated mechanism, normally associated with anti-inflammatory response. During early stages of apoptosis the cell is promptly recognized and engulfed by professional phagocytes or tissue cells to avoid the outflow of intracellular content and limit the immunological reaction against released antigens. However, increasing evidences suggest that impairment in the uptake of apoptotic cell debris is linked to the development of autoimmunity. In fact, autoantigens have been demonstrated to be content within apoptotic bodies and apoptotic cells seems to be critical in the presentation of antigens, activation of innate immunity and regulation of macrophage cytokine secretion. We herein review the known mechanisms for regulating the uptake of the products of apoptosis in the development of autoimmunity.

Lleo, Ana; Selmi, Carlo; Invernizzi, Pietro; Podda, Mauro; Gershwin, M. Eric

2008-01-01

378

Neuronal apoptosis following human brain injury.  

PubMed

Neuronal apoptosis has been investigated in paraffin-embedded brain tissue from 103 individuals who had sustained blunt head injury by use of the in situ nick translation (ISNT) technique. In order to provide reliable data for a forensic wound age estimation, a quantitative morphometric analysis was performed. Apoptotic neuronal cells could be detected in a cortical contusion with a wound age of 45 min at the earliest and in the majority of the cases with postinfliction intervals up to 2 weeks, numerous ISNT-positive cells were found adjacent to the traumatically injured area. The presented data indicate that neuronal apoptosis peaks at about 1 day and persists for at least 22 weeks after blunt head injury. The time-dependent occurrence of apoptotic cells can contribute to a forensic timing of cortical contusions and complements other immunohistochemical parameters, especially in the early postinfliction interval. PMID:14625778

Hausmann, R; Biermann, T; Wiest, I; Tübel, J; Betz, P

2003-11-18

379

Cancer gene therapy targeting cellular apoptosis machinery.  

PubMed

The unraveling of cellular apoptosis machinery provides novel targets for cancer treatment, and gene therapy targeting this suicidal system has been corroborated to cause inflammation-free autonomous elimination of neoplastic cells. The apoptotic machinery can be targeted by introduction of a gene encoding an inducer, mediator or executioner of apoptotic cell death or by inhibition of anti-apoptotic gene expression. Strategies targeting cancer cells, which are achieved by selective gene delivery, specific gene expression or secretion of target proteins via genetic modification of autologous cells, dictate the outcome of apoptosis-based cancer gene therapy. Despite so far limited clinical success, gene therapy targeting the apoptotic machinery has great potential to benefit patients with threatening malignancies provided the availability of efficient and specific gene delivery and administration systems. PMID:22800735

Jia, Lin-Tao; Chen, Si-Yi; Yang, An-Gang

2012-07-15

380

Cardiomyocyte apoptosis in acute and chronic conditions  

Microsoft Academic Search

Myocytes can die by necrosis or by apoptosis and the characteristics of both kinds of cell death are so typical that a differentiation\\u000a can be made by histological and molecular-biological methods using electron microscopy, dUTP labeling with fluorescence or\\u000a peroxidase stainig (TUNEL) and the DNA laddering method. However, the problem of quantification of apoptotic cells has not\\u000a been completely solved

B. Freude; T. N. Masters; S. Kostin; F. Robicsek; J. Schaper

1998-01-01

381

Targeting apoptosis pathways by Celecoxib in cancer.  

PubMed

Celecoxib is a paradigmatic selective inhibitor of cyclooxygenase-2 (COX-2). This anti-inflammatory drug has potent anti-tumor activity in a wide variety of human epithelial tumor types, such as colorectal, breast, non-small cell lung, and prostate cancers. Up to now, the drug found application in cancer prevention in patients with familial adenomatous polyposis. Moreover, the use of Celecoxib is currently tested in the prevention and treatment of pancreatic, breast, ovarian, non-small cell lung cancer and other advanced human epithelial cancers. Induction of apoptosis contributes to the anti-neoplastic activity of Celecoxib. In most cellular systems Celecoxib induces apoptosis independently from its COX-2 inhibitory action via a mitochondrial apoptosis pathway which is however, not inhibited by overexpression of Bcl-2. In addition, Celecoxib exerts antagonistic effects on the anti-apoptotic proteins Mcl-1 and survivin. Consequently, the use of Celecoxib may be of specific value for the treatment of apoptosis-resistant tumors with overexpression of Bcl-2, Mcl-1, or survivin as single drug or in combination with radiotherapy, chemotherapy, or targeted pro-apoptotic drugs that are inhibited by survivin, Bcl-2 or Mcl-1. As COX-2 inhibition has been associated with cardiovascular toxicity, the value of drug derivatives without COX-2 inhibitory action should be validated for prevention and treatment of human epithelial tumors to reduce the risk for heart attack or stroke. However, its additional COX-2 inhibitory action may qualify Celecoxib for a cautious use in COX-2-dependent epithelial tumors, where the drug could additionally suppress COX-2-mediated growth and survival promoting signals from the tumor and the stromal cells. PMID:21345578

Jendrossek, Verena

2011-02-22

382

T cell apoptosis by tryptophan catabolism  

Microsoft Academic Search

Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-catabolizing enzyme that, expressed by different cell types, has regulatory effects on T cells resulting from tryptophan depletion in specific local tissue microenvironments. Different mechanisms, however, might contribute to IDO-dependent immune regulation. We show here that tryptophan metabolites in the kynurenine pathway, such as 3-hydroxyanthranilic and quinolinic acids, will induce the selective apoptosis in vitro

F Fallarino; U Grohmann; C Vacca; R Bianchi; C Orabona; A Spreca; M C Fioretti; P Puccetti

2002-01-01

383

Apoptosis in amphibian organs during metamorphosis  

Microsoft Academic Search

During amphibian metamorphosis, the larval tissues\\/organs rapidly degenerate to adapt from the aquatic to the terrestrial\\u000a life. At the cellular level, a large quantity of apoptosis occurs in a spatiotemporally-regulated fashion in different organs\\u000a to ensure timely removal of larval organs\\/tissues and the development of adult ones for the survival of the individuals. Thus,\\u000a amphibian metamorphosis provides us a good

Atsuko Ishizuya-Oka; Takashi Hasebe; Yun-Bo Shi

2010-01-01

384

NMR exposure sensitizes tumor cells to apoptosis  

Microsoft Academic Search

NMR technology has dramatically contributed to the revolution of image diagnostic. NMR apparatuses use combinations of microwaves\\u000a over a homogeneous strong (1 Tesla) static magnetic field. We had previously shown that low intensity (0.3–66 mT) static magnetic\\u000a fields deeply affect apoptosis in a Ca2+ dependent fashion (Fanelli et al., 1999 FASEBJ., 13;95–102). The rationale of the present study is to examine whether

L. Ghibelli; C. Cerella; S. Cordisco; G. Clavarino; S. Marazzi; M. De Nicola; S. Nuccitelli; M. D'Alessio; A. Magrini; A. Bergamaschi; V. Guerrisi; L. M. Porfiri

2006-01-01

385

Statin-induced apoptosis and skeletal myopathy.  

PubMed

Over 100 million prescriptions were filled for statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) in 2004. Statins were originally developed to lower plasma cholesterol in patients with hypercholesterolemia and are the most effective drugs on the market in doing so. Because of the discovered pleiotropic effects of statins, the use has expanded to the treatment of many other conditions, including ventricular arrythmias, idiopathic dilated cardiomyopathy, cancer, osteoporosis, and diabetes. The elderly population is growing. Therefore, it is estimated that the number of statin users will also increase. Fortunately, the use of statins is relatively safe with few side effects. Myopathy is the most common side effect with symptoms ranging from fatigue, weakness, and pain to symptoms associated with rhabdomyolysis which is a life-threatening condition. The development of statin-induced rhabdomyolysis is rare occurring in approximately 0.1% of patients; however, the occurrence of less severe symptoms is underreported and may be 1-5% or more. Physical exercise appears to increase the likelihood for the development of myopathy in patients taking statins. It is thought that as many as 25% of statin users who exercise may experience muscle fatigue, weakness, aches, and cramping due to statin therapy and potentially dismissed by the patient and physician. The mechanisms causing statin-induced myopathy have not been elucidated; however, research efforts suggest that apoptosis of myofibers may contribute. The mitochondrion is considered a regulatory center of apoptosis, and therefore its role in the induction of apoptosis will be discussed as well as the mechanism of statin-induced apoptosis and myopathy. PMID:16885396

Dirks, Amie J; Jones, Kimberly M

2006-08-02

386

HIV1 viral genes and mitochondrial apoptosis  

Microsoft Academic Search

The mitochondrion is an organelle that regulates various cellular functions including the production of energy and programmed\\u000a cell death. Aberrant mitochondrial function is often concomitant with various cytopathies and medical disorders. The mitochondrial\\u000a membrane plays a key role in the induction of cellular apoptosis, and its destabilization, as triggered by both intracellular\\u000a and extracellular stimuli, results in the release of

Devon J. Shedlock; Daniel Hwang; Andy Y. Choo; Christopher W. Chung; Karuppiah Muthumani; David B. Weiner

2008-01-01

387

Lovastatin Induces Apoptosis in Malignant Mesothelioma Cells  

Microsoft Academic Search

Malignant mesothelioma causes profound morbidity and nearly universal mortality that is refractory to conventional treatment with aggressive surgery, radiotherapy, or chemotherapy. We report that pharmacologic concentrations of lovastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitor, induced apoptosis in human malignant mesothelioma cell lines. Mesothelioma cell viability was decreased in a dose-dependent manner by lovastatin (5 to 30 m M).

JEFFREY B. RUBINS; TODD GREATENS; ROBERT A. KRATZKE; ANNIE T. TAN; VITALY A. POLUNOVSKY; PETER BITTERMAN

1998-01-01

388

Galectins in cell growth and apoptosis  

Microsoft Academic Search

.   Fourteen members of the galectin family, proteins with conserved carbohydrate-recognition domains that bind ?-galactoside,\\u000a have been cloned and more are expected to be discovered in the near future. Many aspects of galectin biology have been thoroughly\\u000a explored, and functional studies have implicated these proteins in cell growth, differentiation and apoptosis, in addition\\u000a to cell adhesion, chemoattraction and cell migration.

R.-Y. Yang; F.-T. Liu

2003-01-01

389

Reactive oxygen species, mitochondria, apoptosis and aging  

Microsoft Academic Search

In this paper, we shall review various antioxygen defense systems of the cell paying particular attention to those that prevent superoxide formation rather than scavenge already formed superoxide and its products. The role of uncoupled, decoupled and non-coupled respiration, mitochondrial pore, mitochondrion-linked apoptosis will be considered. Mitochondrial theory of aging will be regarded in context of reactive oxygen species-induced damage

S. Papa; V. P. Skulachev

1997-01-01

390

Targeting apoptosis pathways in cancer stem cells.  

PubMed

There is a significant void in cancer biology with regard to the elucidation of the mechanisms that underlie tumor formation and progression. Recently, the existence of a hierarchy within cancer cell populations has been demonstrated experimentally for several tumor types. The identification of a tumor cell subset that is capable of self-renewal and, concurrently, generation into more differentiated progeny has engendered new perspectives toward selective targeting of tumors. Although the identification of the so-called "cancer stem cells" (CSCs) is a leap in the study of cancer ontogenesis, therapeutic targeting of such cells is plagued by significant difficulties. CSCs are able to evade the control mechanisms that regulate cell survival and proliferation. Apoptosis is one of the most critical and well-studied mechanisms, governing tissue development and homeostasis through a complex network of molecules that mediate death and survival signals. Escape from such a finely tuned death program is a prerequisite for any tumor-initiating cell. Thus, many compounds have been developed to target cancer cells and induce apoptosis directly or indirectly. Several TRAIL receptor agonists are in Phase I or II trials, and IAP inhibitors are undergoing clinical examination to exploit their ability to enhance ionizing radiation- and chemotherapy-induced apoptosis. Further, the EGF-R/Akt pro-survival signaling axis is one of the most frequently explored sources of targets for indirect apoptosis induction, as evidenced by the significant amount of molecules designed to target this pathway and have been approved by the FDA or are under clinical evaluation. Despite the promise of these magic bullets, the absence of reliable clinical models has considerably diminished the therapeutic potential of targeted therapies considerably. A more systematic molecular characterization of the tumor-initiating cell population in many tumors will allow us to refine the stimuli that force CSCs to die, thus accelerating the development of more effective treatment for cancer. PMID:21315505

Signore, Michele; Ricci-Vitiani, Lucia; De Maria, Ruggero

2011-02-10

391

Cellular remodelling by apoptosis during porcine placentation.  

PubMed

The mechanisms that regulate the apoptosis are essential to the normal development and maintenance of homoeostasis and play an important role in placental development in mammals. During porcine pregnancy, there must be a proper cellular remodelling to achieve a normal gestational development. Knowledge of pig physiology during pregnancy will explore options to increase the productivity of this species of high economical value. The purpose of this work was to study the cell morphology and apoptosis of porcine placentas from early, mid and late pregnancy. For that purpose, high-resolution light microscopy and transmission electron microscopy were performed to the study of cell morphology. TUNEL, the apoptosis index (IAp) and the expression of c-FLIP through immunohistochemistry technique were used to the study of apoptosis. High-resolution light microscopy and transmission electron microscopy confirmed the presence of placental cells with ultrastructural apoptotic features. Apoptotic nuclei were detected by TUNEL in different placental structures and phagocytes containing apoptotic bodies. The IAp in villi was 9.34% at early, 0.82% at mid and 23.85% at late pregnancy. Statistically significant differences were found between periods (p < 0.05). In previous studies, we determined a differential induction of the apoptotic routes in the placental villi in agreement with the gestational period. A co-expression of receptors and mitochondrial proteins in placental connective tissue was detected, but the immunolocalization of c-FLIP would indicate an endogenous inhibition of the extrinsic pathway. In conclusion, in swine there exists differential activation of inducing apoptotic pathways in different placental structures according to the gestational period. PMID:23398294

Cristofolini, A; Sanchis, G; Moliva, M; Alonso, L; Chanique, A; Koncurat, M; Merkis, C

2013-02-11

392

ICE-related proteases in apoptosis.  

PubMed

Apoptotic execution involves numerous enzymatic pathways, all of which appear to be triggered by the activation of one or more ICE-related proteases (IRPs). Considerable effort is currently being expended in the identification and functional characterization of the rapidly expanding superfamily of IRPs. Important questions that remain unsolved include the identity of the vertebrate IRP that triggers the apoptotic cascade and the identities of the crucial substrates whose cleavage results in the dramatic morphological changes during apoptosis. PMID:8791488

Takahashi, A; Earnshaw, W C

1996-02-01

393

BIOCHEMICAL PATHWAYS OF CASPASE ACTIVATION DURING APOPTOSIS  

Microsoft Academic Search

? Abstract Caspase activation plays a central role in the execution of apoptosis. The key components,of the biochemical,pathways,of caspase activation have been recently elucidated. In this review, we focus on the two most well-studied pathways of caspase activation: the cell surface death receptor pathway,and the mitochondria- initiated pathway. In the cell surface death receptor pathway, activation of caspase-8 following its

Imawati Budihardjo; Holt Oliver; Michael Lutter; Xu Luo; Xiaodong Wang

1999-01-01

394

Targeting apoptosis pathways in lung cancer.  

PubMed

Lung cancer is a devastating disease with a poor prognosis. Non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) represent different forms of lung cancer that are associated with distinct genetic causes and display different responses to therapy in the clinic. Whereas SCLC is often sensitive to chemotherapy at start of treatment, NSCLC are less chemo-sensitive. In NSCLC different histological subtypes are distinguished and increasing efforts are made to identify subtypes that respond to specific therapies, such as those harbouring epidermal growth factor receptor (EGFR) mutations that have benefit from treatment with EGFR inhibitors. Targeting of the apoptotic machinery represents another approach that aims to selectively kill cancer cells while sparing normal ones. Here we describe different ways that are currently explored to induce apoptosis in lung cancer cells, specifically pathways controlled by TNF-related apoptosis-inducing ligand (TRAIL), BCL-2 family members and apoptosis inhibitory proteins (IAPs). Preclinical studies are discussed and for some agents results from early clinical studies and future perspectives are considered. PMID:20974517

Pore, Milind M; Hiltermann, T Jeroen N; Kruyt, Frank A E

2010-10-25

395

Apoptosis in hepatitis C virus infection.  

PubMed

Infection with hepatitis C virus (HCV) is characterized by inflammatory liver damage and a long viral persistence associated with an increased risk of developing hepatocellular carcinoma. Both in liver damage and in oncogenesis a disturbance of apoptosis has been implicated, although the underlying mechanisms in these apparently opposite processes are incompletely understood. HCV-triggered liver injury is mediated mainly by host immune mechanisms and eventually by direct cytopathic effects of HCV. Recent data shows that caspase activation, either triggered by death ligands, other cytokines, granzyme B or HCV proteins, is considerably upregulated in HCV-infected liver. Interestingly, caspase activation appears to correlate closely with the inflammatory response. Data about the role of single HCV proteins, either in cultured cells or transgenic animals models, however, are contradictory, as both pro- and anti-apoptotic effects have been observed. Nevertheless, apoptosis induction upon HCV infection may critically contribute to liver damage, while inhibition of apoptosis may result in HCV persistence and development of hepatocellular carcinoma. PMID:12655346

Bantel, H; Schulze-Osthoff, K

2003-01-01

396

Pharmacological regulation of neutrophil activity and apoptosis  

PubMed Central

Novel strategies of antiinflammatory therapy are based upon pharmacological agents capable to enhance the resolution – i.e. the termination of the beneficial inflammation before it may turn into an adverse chronic stage. In contrast to the current therapy, which antagonises the formation of proinflammatory mediators, the “proresolving” therapy promotes natural antiinflammatory processes. It is likely that several drugs and phytochemicals would act in this way, but this point has not been investigated and thus might be totally overlooked. In this paper, effects of curcumin (diferuloylmethane) were analysed, considering the ability of this natural compound to affect resolution of inflammation through modulation of its important inputs – activity and apoptosis of neutrophils. The presented data indicate that, besides its well-known ability to suppress mechanisms engaged at the onset and progression of inflammation, curcumin could support resolution of inflammation through decreased activity and enhanced apoptosis of neutrophils. This substance decreased the formation of oxidants in neutrophils, both under in vitro conditions and after oral administration to arthritic rats. Moreover, curcumin accelerated spontaneous apoptosis of neutrophils, as indicated by increased externalisation of phosphatidylserine, by intercalation of propidium iodide and by enhanced activity of the executioner caspase-3.

Jancinova, Viera; Perecko, Tomas; Nosal, Radomir; Mihalova, Danica; Bauerova, Katarina; Drabikova, Katarina

2011-01-01

397

Extract of Cassiae Semen and its major compound inhibit S100b-induced TGF-beta1 and fibronectin expression in mouse glomerular mesangial cells.  

PubMed

Non-enzymatic glycation reactions between reducing sugar and free reactive amino groups of protein lead to the formation of advanced glycation end products, which increase under conditions of aging or diabetes. A previous study showed that extracts of Cassiae Semen (CS), the seed of Cassia tora, had inhibitory activity on advanced glycation end products formation in vitro. To examine the pharmacological effects of a butanol-soluble extract of CS under conditions of diabetic nephropathy, we evaluated the expression of transforming growth factor-beta1 (TGF-beta1) and fibronectin, key mediators of diabetic nephropathy, in mouse glomerular mesangial cells cultured in the presence of S100b (a specific ligand for receptor of advanced glycation end products). CS inhibited S100b-induced TGF-beta1 and fibronectin expression in mouse mesangial cells by suppressing activation of Smad2/3, extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK), and oxidative stress. Moreover, CS suppressed nuclear factor-kappa B (NF-kappaB) activation in S100b-stimulated mouse mesangial cells. To identify the active compounds of CS, three major compounds, rubrofusarin-6-O-beta-d-gentiobioside (CS-A), toralactone-9-O-beta-d-gentiobioside (CS-B), and cassiaside (CS-C), were tested in cells. Of these compounds, CS-A significantly decreased the expression of TGF-beta1 and fibronectin and NF-kappaB DNA binding activity. These findings suggest that CS, especially CS-A, has potential as a preventive agent for advanced glycation end products-related diabetic complications. PMID:20483351

Jung, Dong Ho; Kim, Young Sook; Kim, Nan Hee; Lee, Jun; Jang, Dae Sik; Kim, Jin Sook

2010-05-17

398

Screening of UV-B-induced genes from apple peels by SSH: possible involvement of MdCOP1-mediated signaling cascade genes in anthocyanin accumulation.  

PubMed

Suppression subtractive hybridization (SSH) was employed to identify candidate genes involved in red coloration in apple peel with the ultraviolet (UV)-B-treated 'Mutsu'. After reverse Northern blotting verification, nearly 80 clones were successfully sequenced. Large portions of the expressed sequence tags (ESTs) are well characterized anthocyanin biosynthesis-related genes, such as chalcone synthase (11A5), flavonol synthase (12F3), anthocyanidin synthase (11H5) and UDP-glycosyl transferase (14A12) whose presence proved the success of SSH. Eight ESTs were selected for quantitative real-time polymerase chain reaction analysis and their expressions were all elevated in 'Induction', further confirming the reliability of the SSH library. One EST, 11F4 (CONSTITUTIVE PHOTOMORPHOGENIC 1: COP1) with putative function in light signal relay was further analyzed in 'Mutsu' and 'Tsugaru', along with MdHY5 (ELONGATED HYPOCOTYL 5: the downstream target of COP1), MdMYB22 (a possible flavonol-specific activator under the regulation of HY5, belonging to the SG7/PRODUCTION OF FLAVONOL GLYCOSIDES family) and MdMYBA. Results showed that MdCOP1, MdHY5, MdMYB22 and MdMYBA were all UV-B inducible genes and anthocyanin accumulation occurred after their increased expressions. Moreover, their expressions and anthocyanin content were enhanced under UV-B plus 17°C treatment. The presence of G box, a known consensus binding site of HY5, in the MdMYBA promoter region implicated that it could be regulated by MdHY5, which was verified by the result of the yeast one-hybrid analysis. Our data suggested that UV-B irradiation would induce the utmost upstream light signaling factor, MdCOP1, which activates MdHY5 signaling by binding to the promoter regions of MdMYBs, and finally leads to the red coloration of apple peels. PMID:23171407

Peng, Ting; Saito, Takanori; Honda, Chikako; Ban, Yusuke; Kondo, Satoru; Liu, Ji-Hong; Hatsuyama, Yoshimichi; Moriguchi, Takaya

2012-11-21

399

HIV increases HCV-induced hepatocyte apoptosis  

PubMed Central

Background and Aims HCV related liver disease is one of the most important complications in persons with HIV, with accelerated fibrosis progression in coinfected persons compared to those with HCV alone. We hypothesized that HIV coinfection increases HCV related hepatocyte apoptosis and that HCV and HIV influence TRAIL signaling in hepatocytes. Methods We analyzed the effect of HIV on JFH1-infected Huh 7.5.1 cells. Apoptosis was measured by Caspase-Glo 3/7 assay and Western blot for cleaved PARP. TRAIL, TRAIL receptor 1 (DR4) and 2 (DR5) mRNA and protein levels were assessed by real-time PCR and Western blot. We also investigated activation of caspase pathways using caspase inhibitors and assessed expression of Bid and cytochrome C. Results We found increased caspase 3/7 activity and cleaved PARP in JFH1 HCV-infected Huh7.5.1 cells in the presence of heat-inactivated HIV compared to Huh7.5.1 cells infected with JFH1 or exposed to heat-inactivated HIV alone. Both DR4 and DR5 mRNA and protein expression were increased in JFH1-infected cells in the presence of inactivated HIV compared to Huh7.5.1 cells infected with JFH1 or exposed to heat-inactivated HIV alone. Pancaspase, Caspase-8, and caspase-9 inhibition blocked apoptosis induced by HCV, inactivated HIV and HCV plus inactivated HIV. A caspase-9 inhibitor blocked apoptosis induced by HCV, HIV and HCV-HIV comparably to pancaspase and caspase-8 inhibitors. HCV induced the activation of Bid cleavage and cytochrome C release. The addition of HIV substantially augmented this induction. Conclusions Our findings indicate that hepatocyte apoptosis is increased in the presence of HCV and HIV compared to HCV or HIV alone, and that this increase is mediated by DR4 and DR5 up-regulation. They provide an additional mechanism for the observed accelerated liver disease progression observed in HCV-HIV coinfection.

Jang, Jae Young; Shao, Run-Xuan; Lin, Wenyu; Weinberg, Ethan; Chung, Woo Jin; Tsai, Wei Lun; Zhao, Hong; Goto, Kaku; Zhang, Leiliang; Mendez-Navarro, Jorge; Jilg, Nikolaus; Peng, Lee F.; Brockman, Mark A.; Chung, Raymond T.

2010-01-01

400

Tumor Necrosis Factor ?-induced Inflammation Is Increased but Apoptosis Is Inhibited by Common Food Additive Carrageenan*  

PubMed Central

Tumor necrosis factor (TNF)-?, a homotrimeric, pleiotropic cytokine, is secreted in response to inflammatory stimuli in diseases such as rheumatoid arthritis and inflammatory bowel disease. TNF-? mediates both apoptosis and inflammation, stimulating an inflammatory cascade through the non-canonical pathway of NF-?B activation, leading to increased nuclear RelB and p52. In contrast, the common food additive carrageenan (CGN) stimulates inflammation through both the canonical and non-canonical pathways of NF-?B activation and utilizes the adaptor molecule BCL10 (B-cell leukemia/lymphoma 10). In a series of experiments, colonic epithelial cells and mouse embryonic fibroblasts were treated with TNF-? and carrageenan in order to simulate the possible effects of exposure to dietary CGN in the setting of a TNF-?-mediated inflammatory disease process. A marked increase in secretion of IL-8 occurred, attributable to synergistic effects on phosphorylated NF-?B-inducing kinase (NIK) in the non-canonical pathway. TNF-? induced the ubiquitination of TRAF2 (TNF receptor-associated factor 2), which interacts with NIK, and CGN induced phosphorylation of BCL10, leading to increased NIK phosphorylation. These results suggest that TNF-? and CGN in combination act to increase NIK phosphorylation, thereby increasing activation of the non-canonical pathway of NF-?B activation. In contrast, the apoptotic effects of TNF-?, including activation of caspase-8 and PARP-1 (poly(ADP-ribose) polymerase 1) fragmentation, were markedly reduced in the presence of CGN, and CGN caused reduced expression of Fas. These findings demonstrate that exposure to CGN drives TNF-?-stimulated cells toward inflammation rather than toward apoptotic cell death and suggest that CGN exposure may compromise the effectiveness of anti-TNF-? therapy.

Bhattacharyya, Sumit; Dudeja, Pradeep K.; Tobacman, Joanne K.

2010-01-01

401

Examining the cellular pathways involved in influenza virus induced apoptosis.  

PubMed

Apoptosis is essential in many physiological processes including wound healing and development of the immune response. Apoptosis also plays an important role in the pathogenesis of many infectious diseases including those caused by viruses. Influenza viruses induce apoptosis in cells that are permissive for viral replication and cells that do not support viral replication. The cellular pathways involved in influenza virus induced apoptosis are currently ill defined. Previous studies suggest that influenza virus infection increased the expression of the Fas antigen in HeLa cells, and that Fas antigen is partially involved in apoptosis. In these studies we examined the cellular pathways involved in avian influenza virus induced apoptosis in two cell lines that support productive viral replication: Madin-Darby canine kidney cells (MDCK) and mink lung epithelial (Mv1Lu) cells. PMID:14575095

Schultz-Cherry, S; Koci, M; Thompson, E; Tumpey, T M

2003-01-01

402

The actin cytoskeleton as a sensor and mediator of apoptosis  

PubMed Central

Apoptosis is an important biological process required for the removal of unwanted or damaged cells. Mounting evidence implicates the actin cytoskeleton as both a sensor and mediator of apoptosis. Studies also suggest that actin binding proteins (ABPs) significantly contribute to apoptosis and that actin dynamics play a key role in regulating apoptosis signaling. Changes in the organization of the actin cytoskeleton has been attributed to the process of malignant transformation and it is hypothesized that remodeling of the actin cytoskeleton may enable tumor cells to evade normal apoptotic signaling. This review aims to illuminate the role of the actin cytoskeleton in apoptosis by systematically analyzing how actin and ABPs regulate different apoptosis pathways and to also highlight the potential for developing novel compounds that target tumor-specific actin filaments.

Desouza, Melissa; Gunning, Peter W.; Stehn, Justine R.

2012-01-01

403

Artesunate induces AIF-dependent apoptosis in A549 cells  

NASA Astrophysics Data System (ADS)

Artesunate (ART), a semi-synthetic derivative of the sesquiterpene artemisinin extracted from the Chinese herb Artemisia annua, exerts a broad spectrum of clinical activity against human cancers. It has been shown that ART induces cancer cells death through apoptosis pathway. This study investigated whether ART treatment induced reactive oxygen species (ROS)-dependent cell death in the apoptosis fashion in human lung adenocarconoma A549 cell line and the proapoptotic protein apoptosis inducing factor (AIF) is involved in ART-induced apoptosis. Cells treated with ART exhibited typical apoptotic morphology as chromatin condensation, margination and shrunken nucleus. ART treatment also induced a loss of mitochondrial membrane potential and AIF release from mitochondria. Silencing AIF can remarkable attenuated ART-induced apoptosis. Collectively, ART induces apoptosis by caspase-independent intrinsic pathway in A549 cells.

Zhou, Chen-Juan; Chen, Tong-Sheng

2012-02-01

404

A Novel Protein Expressed in Mammalian Cells Undergoing Apoptosis  

Microsoft Academic Search

Human and rodent cells undergoing apoptosis were observed to express high levels of a novel 45,000 Mr protein. The protein, which we have termed apoptosis specific protein (ASP), was found in Burkitt lymphoma (BL) cells and in adenovirus-transformed human and rat embryo cells induced into apoptosis by a variety of stimuli, including serum deprivation, exposure to the Ca2+ ionophore, ionomycin,

Roger J. A. Grand; Anne E. Milner; Tracey Mustoe; Gerald D. Johnson; Darerca Owen; Michael L. Grant; Christopher D. Gregory

1995-01-01

405

Apoptosis is present in the primate macula at all ages  

Microsoft Academic Search

Background: It has become increasingly clear that apoptosis is a main event in photoreceptor cell death in a variety of retinal degenerations.\\u000a We investigated the role of apoptosis in the physiologically aging primate macula.Methods: Twenty maculae of rhesus monkeys, aged 6–34 years, were investigated. Apoptosis was determined in formalin-fixed, paraffin-embedded\\u000a eyes using the TUNEL (TdT-mediated dUTP-biotin nick end labeling) method

Antoinette C. Lambooij; Mike Kliffen; Robert W. A. M. Kuijpers; Adriaan B. Houtsmuller; Johan J. Broerse; Cornelia M. Mooy

2000-01-01

406

An inflammatory micro-environment promotes human adipocyte apoptosis  

Microsoft Academic Search

Obesity-associated macrophage infiltration into adipose tissue is responsible for both local and systemic inflammation. Recent findings suggest fat cell apoptosis as an initiator of macrophage recruitment.Here, we investigated the effects of an inflammatory micro-environment on fat cells using human THP-1 macrophages and SGBS adipocytes. Macrophage-secreted factors induced insulin resistance, inhibited insulin-stimulated Akt phosphorylation, and induced apoptosis of adipocytes. The apoptosis-inducing

Michaela Keuper; Matthias Blüher; Michael R. Schön; Peter Möller; Anna Dzyakanchuk; Kurt Amrein; Klaus-Michael Debatin; Martin Wabitsch; Pamela Fischer-Posovszky

2011-01-01

407

Baculoviruses and apoptosis: the good, the bad, and the ugly  

Microsoft Academic Search

Since 1991, when a baculovirus was first shown to inhibit apoptosis of its host insect cells, considerable contributions to our knowledge of apoptosis have arisen from the study of these viruses and the anti-apoptotic genes they encode. Baculovirus anti-apoptotic genes include p35, which encodes the most broadly acting caspase inhibitor protein known, and iap (inhibitor of apoptosis) genes, which were

R J Clem

2001-01-01

408

Implication of Polyamines in Apoptosis of Immunoresponse Cells  

Microsoft Academic Search

In many diseases, including host response to pathogens, dysregulation of the immune system is a hallmark. An important component\\u000a of such events is alterations in apoptosis of immune cells. This may include failure of apoptosis, but most commonly involves\\u000a loss of immune function from death of immune cells. We will review the role of polyamines in immune cell apoptosis and

Rupesh Chaturvedi; Keith T. Wilson

409

Apoptosis Induction by Epigallocatechin Gallate Involves Its Binding to Fas  

Microsoft Academic Search

Epigallocatechin gallate (EGCG) is known to induce apoptosis in various types of tumor cells, but the precise mechanism by which EGCG induces apoptosis remains to be elucidated. The Fas–Fas ligand system is one of the major pathways operating in the apoptotic cascade. The aim of this study was to examine the possibility that EGCG-binding to Fas triggers the Fas-mediated apoptosis.

Sumio Hayakawa; Koichi Saeki; Masaki Sazuka; Yasuo Suzuki; Yutaka Shoji; Toshiro Ohta; Kazuhiko Kaji; Akira Yuo; Mamoru Isemura

2001-01-01

410

Induction of gastric epithelial apoptosis by Helicobacter pylori  

Microsoft Academic Search

BACKGROUND--Helicobacter pylori may promote gastric carcinogenesis through increasing gastric epithelial cell proliferation. How H pylori does so is unknown. Programmed, non-necrotic, cell death (apoptosis) occurs throughout the gut and is linked to proliferation. It was hypothesised that H pylori may induce hyper-proliferation through increasing apoptosis. AIM--To measure the effect of H pylori infection on gastric epithelial apoptosis in situ. PATIENTS--Patients

S F Moss; J Calam; B Agarwal; S Wang; P R Holt

1996-01-01

411

Apoptosis versus oncotic necrosis in hepatic ischemia\\/reperfusion injury  

Microsoft Academic Search

Warm and cold hepatic ischemia followed by reperfusion leads to necrotic cell death (oncosis), which often occurs within minutes of reperfusion. Recent studies also suggest a large component of apoptosis after ischemia\\/reperfusion. Here, we review the mechanisms underlying adenosine triphosphate depletion—dependent oncotic necrosis and caspase-dependent apoptosis, with emphasis on shared features and pathways. Although apoptosis causes internucleosomal DNA degradation that

Hartmut Jaeschke; John J Lemasters

2003-01-01

412

Pseudolaric acid B-induced autophagy contributes to senescence via enhancement of ROS generation and mitochondrial dysfunction in murine fibrosarcoma L929 cells.  

PubMed

Pseudolaric acid B (PAB) is the primary biologically active compound isolated from the root bark of P. kaempferi Gordon. Our previous study demonstrated that PAB induced mitotic catastrophe in L929 cells and indicated that only a small percentage (12%) of the cells undergoing mitotic catastrophe displayed an apoptotic phenotype after PAB treatment for 72 h. In this study, we found that a minority of the cells undergoing mitotic catastrophe ended in apoptosis, and a majority of them entered a period of senescence. Further data confirmed that PAB induced autophagy, reactive oxygen species (ROS) generation, and mitochondrial dysfunction in L929 cells. Subsequently, we found that autophagy inhibitors significantly delayed the senescence process, indicating that autophagy facilitated senescence. Moreover, ROS scavenger significantly decreased the autophagic level and improved mitochondrial function. Additionally, autophagy inhibitors effectively reduced ROS levels and ameliorated mitochondrial function. In conclusion, autophagy promoted senescence via enhancement of ROS generation and mitochondrial dysfunction in PAB-treated L929 cells. PMID:23439612

Qi, Min; Fan, Simiao; Yao, Guodong; Li, Zhao; Zhou, Haiyan; Tashiro, Shin-ichi; Onodera, Satoshi; Xia, Mingyu; Ikejima, Takashi

2013-02-23

413

Apoptosis in the vasculature: mechanisms and functional importance  

PubMed Central

Apoptotic death has now been recognized in a number of common and threatening vascular diseases, including atherosclerosis. Interest in apoptosis research relates to the fact that apoptosis, in contrast to oncosis, is a highly regulated process of cell death which raises the hope for the development of specific therapeutic strategies to alter disease progression. This review summarizes the mechanisms involved in vascular endothelial and smooth muscle cell survival/apoptosis, and the potential roles of apoptotic death in atherosclerosis and restenosis. The potential effects of modulation of apoptosis in these diseases are also discussed.

Mallat, Ziad; Tedgui, Alain

2000-01-01

414

Shifting the balance of mitochondrial apoptosis: therapeutic perspectives  

PubMed Central

Signaling via the intrinsic (mitochondrial) pathway of apoptosis represents one of the critical signal transduction cascades that control the regulation of cell death. This pathway is typically altered in human cancers, thereby providing a suitable target for therapeutic intervention. Members of the Bcl-2 family of proteins as well as cell survival signaling cascades such as the PI3K/Akt/mTOR pathway are involved in the regulation of mitochondria-mediated apoptosis. Therefore, further insights into the molecular mechanisms that form the basis for the control of mitochondria-mediated apoptosis will likely open new perspectives to bypass evasion of apoptosis and treatment resistance in human cancers.

Fulda, Simone

2012-01-01

415

Detection and quantification of apoptosis in transiently transfected adherent cells.  

PubMed

Apoptosis is a highly conserved form of cell death present in all eukaryotic cell types and controlled by multiple genes. Several methods have been developed to quantify apoptosis, but none is adapted for all cell types. It is particularly difficult to reliably assay apoptosis of adherent cells. We describe a new, rapid and reliable flow cytometric method which can be used for quantifiying apoptosis in a sub-population of transiently transfected adherent cells. This technique is based on the detection of transfected cells and the apoptotic sub-population by immunofluorescence and Annexin-V labelling, respectively. PMID:9801327

Lassus, P; Hibner, U

1998-11-15

416

Detection and quantification of apoptosis in transiently transfected adherent cells.  

PubMed Central

Apoptosis is a highly conserved form of cell death present in all eukaryotic cell types and controlled by multiple genes. Several methods have been developed to quantify apoptosis, but none is adapted for all cell types. It is particularly difficult to reliably assay apoptosis of adherent cells. We describe a new, rapid and reliable flow cytometric method which can be used for quantifiying apoptosis in a sub-population of transiently transfected adherent cells. This technique is based on the detection of transfected cells and the apoptotic sub-population by immunofluorescence and Annexin-V labelling, respectively.

Lassus, P; Hibner, U

1998-01-01

417

Apoptosis in vascular cells induced by cold atmospheric plasma treatment  

NASA Astrophysics Data System (ADS)

Apoptosis is a natural mechanism of cellular self-destruction. It can be triggered by moderate, yet irreversible damage. Apoptosis plays a major role in tissue renewal. Artificial apoptosis induction will become a novel therapy that meets all requirements for tissue-saving surgery. Diseased tissues can disappear without inflammation and scarring. This is particularly important in treatment of blockages in body tracts (e.g. cardiovascular diseases). Artificial induction of apoptosis can be achieved by means of cold plasma treatment. In this work an atmospheric micro-plasma operated in helium/air has been used to induce apoptosis in vascular cells. Parametric studies of apoptosis induction have been conducted; the efficiency is almost 100%. The apoptotic factors are ROS/RNS (reactive oxygen and nitrogen species). Their densities in the plasma have been measured by mass spectrometry. For apoptosis induction, RNS seem to be more important than ROS, because of their relative abundance. Moreover, addition of a ROS scavenger (ascorbic acid) to the cell culture medium does not reduce the occurrence of apoptosis. Cold plasma is a very efficient tool for fundamental studies of apoptosis, and later, for controlled tissue removal in vivo.

Sladek, Raymond; Stoffels, Eva

2006-10-01

418

[Apoptosis, its mechanisms and medical significance. I. Definition of apoptosis and its progression at the cellular level].  

PubMed

Apoptosis is a one example of genetically-regulated cell death. It is characterized by the phylogenetically highly conserved activation of specific genes and proteins followed by energy-consuming proteolytic autodestruction. Apoptosis seems to be physiological and highly selective mechanism to eliminate either old or injured cells in organisms. It is in contrary to mitosis. A highly complex combination of various stimuli both extracellular and intracellular origins is required for induction of apoptosis together with preserved oxidative phosphorylation. PMID:11494884

Novosad, J; Kodydková, K; Krejsek, J

2001-06-01

419

Cardiac Apoptosis in Severe Relapsing Fever Borreliosis  

PubMed Central

Previous studies revealed that the heart suffers significant injury during experimental Lyme and relapsing fever borreliosis when the immune response is impaired (D. Cadavid, Y. Bai, E. Hodzic, K. Narayan, S. W. Barthold, and A. R. Pachner, Lab. Investig. 84:1439-1450, 2004; D. Cadavid, T. O'Neill, H. Schaefer, and A. R. Pachner, Lab. Investig. 80:1043-1054, 2000; and D. Cadavid, D. D. Thomas, R. Crawley, and A. G. Barbour, J. Exp. Med. 179:631-642, 1994). To investigate cardiac injury in borrelia carditis, we used antibody-deficient mice persistently infected with isogenic serotypes of the relapsing fever agent Borrelia turicatae. We studied infection in hearts 1 to 2 months after inoculation by TaqMan reverse transcription-PCR and immunohistochemistry (IHC) and inflammation by hematoxylin and eosin and trichrome staining, IHC, and in situ hybridization (ISH). We studied apoptosis by terminal transferase-mediated DNA nick end labeling assay and measured expression of apoptotic molecules by RNase protection assay, immunofluorescence, and immunoblot. All antibody-deficient mice, but none of the immunocompetent controls, developed persistent infection of the heart. Antibody-deficient mice infected with serotype 2 had more severe cardiac infection and injury than serotype 1-infected mice. The injury was more severe around the base of the heart and pericardium, corresponding to sites of marked infiltration by activated macrophages and upregulation of interleukin-6 (IL-6). Infected hearts showed evidence of apoptosis of macrophages and cardiomyocytes as well as significant upregulation of caspases, most notably caspase-1. We conclude that persistent infection with relapsing fever borrelias causes significant loss of cardiomyocytes associated with prominent infiltration by activated macrophages, upregulation of IL-6, induction of caspase-1, and apoptosis.

Londono, Diana; Bai, Yunhong; Zuckert, Wolfram R.; Gelderblom, Harald; Cadavid, Diego

2005-01-01

420

FAT10 protects cardiac myocytes against apoptosis.  

PubMed

FAT10 is a new member of the ubiquitin-like protein family with yet-to-be defined biological functions in the heart. Our objective was to determine the role of FAT10 in the heart. FAT10 is expressed in the normal human and murine hearts, as detected by qPCR and Western blotting. Expression of FAT10 is increased in the heart at the border zone of myocardial infarction and in cultured neonatal rat cardiac myocytes (NRCM) subjected to hypoxia/reoxygenation (H/R) stress. Lentiviral-mediated overexpression of FAT10 in NRCM reduced p53 (TP53) and its target miR-34a levels, while BCL2 level, a target of miR-34a, was increased and BAX level, a pro-apoptotic protein, was reduced. These changes were associated with reduced apoptosis, detected by FACS analysis of annexin-V expression and TUNEL assay, in response to H/R injury. Knock down of FAT10 by shRNA targeting had the opposite effects. Likewise, lentiviral mediated expression of miR-34a was associated with reduced BCL2 and increased BAX levels in NRCM and also reversed changes in BCL-2 and BAX levels observed upon over-expression of FAT10. Treatment of NRCM with proteasome inhibitor MG132 increased p53 and miR-34a levels and reduced BLC2/BAX ratio. These changes were not reversed upon over-expression of FAT10. Thus, FAT10 is upregulated in the heart and NRCM in response to H/R stress, which protects cardiac myocytes against apoptosis. The anti-apoptotic effects of FAT10 are associated with suppression of p53, probably through fatylation and proteasomal degradation, reduced miR-34a expression, and a shift in the BCL2/BAX proteins against apoptosis. Thus, FAT10 is a cardioprotective protein. PMID:23416168

Peng, Xiaogang; Shao, Jianghua; Shen, Yang; Zhou, Yunguo; Cao, Qing; Hu, Jinzhu; He, Wenfeng; Yu, Xin; Liu, Xiuxia; Marian, Ali J; Hong, Kui

2013-02-13

421

The neuronal apoptosis inhibitory protein suppresses neuronal differentiation and apoptosis in PC12 cells  

Microsoft Academic Search

The human neuronal apoptosis inhibitory protein (NAIP) gene has been discovered as a candidate gene for spinal muscular atrophy, a genetic disorder characterized by motor neuron loss in the spinal cord. The telo- meric NAIP gene on human chromosome 5 is deleted together with survival motor neurons (SMN) in many cases of the most severe forms of the disorder. NAIP,

R. Gotz; Matthew R. Digby; Jakob Troppmair; R. Rapp; Michael Sendtner

2000-01-01

422

Fas-Activated Apoptosis and Apoptosis Mediators in Human Trabecular Meshwork Cells  

Microsoft Academic Search

A gradual loss of cells occurs within the human trabecular meshwork during normal aging and appears to be increased in patients with primary open-angle glaucoma. The exact mechanism by which cells are lost in either condition is not known, however phagocytosis, cell migration and cell death have been suggested. Apoptosis is one method by which cell death can occur. We

RAJNEE AGARWAL; MIHIR TALATI; WENDI LAMBERT; ABBOT F CLARK; STEVEN E WILSON; NEERAJ AGARWAL; ROBERT J WORDINGER

1999-01-01

423

Apoptosis in cultured hNT neurons.  

PubMed

Programmed cell death (apoptosis) is an important mechanism shaping the size of different cell populations within the developing nervous system. In our study we used the NT2/D1 clone originally established from the Ntera 2 cell line to investigate the baseline levels of apoptosis in cultured postmitotic hNT (NT2-N) neurons previously treated for 3, 4 or 5 weeks with retinoic acid (RA) and compared it with apoptosis in NT2 precursors unexposed to RA. First, we examined whether different lengths of exposure to RA might affect baseline apoptotic rate in differentiating hNT neurons. Second, we investigated whether cultured hNT neurons, previously shown to possess dopaminergic characteristics, would be preferentially affected by apoptosis. Using the terminal deoxynucleotidyl transferase (tdt)-labeling technique we found that the postmitotic hNT neuronal cells exposed to RA demonstrated significantly higher numbers of apoptotic cells (12.5-15.8%) in comparison to rapidly dividing NT2 precursor cell line (3.6-4.4%) at both studied (1 and 5 days in vitro, DIV) time points. Similar apoptotic nuclear morphology, including a variable extent of nuclear fragmentation was observed in all examined hNT cultures. On the other hand, the incidence of apoptotic nuclei was rare in cultures of NT2 precursors not subjected to RA treatment. Combined immunocytochemistry for tyrosine hydroxylase (TH) and Hoechst staining revealed dopaminergic hNT neurons destined to die. Our double-labeling studies have demonstrated that only a subset of TH-positive hNT cells had condensed chromatin after 1 (approx. 15%) and 5 (approx. 20%) DIV. NT2 precursors were not TH-positive. Collectively, our results demonstrated that exposure to differentiating agent RA triggers an apoptotic commitment in a subset of postmitotic hNT neurons. These results suggest that this cell line may serve as a model of neuronal development to test various pathogenic factors implicated in the etiology of Parkinson's disease (PD), as well as to screen numerous pharmacological treatments that may slow or prevent dopaminergic deterioration. PMID:11287065

Zigova, T; Willing, A E; Saporta, S; Daadi, M M; McGrogan, M P; Randall, T S; Freeman, T B; Sanchez-Ramos, J; Sanberg, P R

2001-03-29

424

Apoptosis and gene expression after TBI.  

PubMed

Proper CNS function depends on concerted expression of thousands of genes in a controlled and timely manner. Traumatic brain injury (TBI) in humans results in neuronal death and neurological dysfunction, which might be mediated by altered expression of several genes. By employing a CNS-specific GeneChip and real time polymerase chain reaction (PCR), the study analyzed the gene expression changes. The findings of necrosis and apoptosis can help to improve the wound age estimation after TBI in legal medicine. PMID:19282216

Dressler, Jan; Vemuganti, Raghu

2009-03-17

425

CHEMOSENSITIZATION BY A NON-APOPTOGENIC HEAT SHOCK PROTEIN 70-BINDING APOPTOSIS INDUCING FACTOR MUTANT  

EPA Science Inventory

Chemosensitization by a non-apoptogenic heat shock protein 70-binding apoptosis inducing factor mutant Abstract HSP70 inhibits apoptosis by neutralizing the caspase activator Apaf-1 and by interacting with apoptosis inducing factor (AIF), a mitochondrial flavoprotein wh...

426

The genomic underpinnings of apoptosis in the silkworm, Bombyx mori  

PubMed Central

Background Apoptosis is regulated in an orderly fashion by a series of genes, and has a crucial role in important physiological processes such as growth development, immunological response and so on. Recently, substantial studies have been undertaken on apoptosis in model animals including humans, fruit flies, and the nematode. However, the lack of genomic data for silkworms limits their usefulness in apoptosis studies, despite the advantages of silkworm as a representative of Lepidoptera and an effective model system. Herein we have identified apoptosis-related genes in the silkworm Bombyx mori and compared them to those from insects, mammals, and nematodes. Results From the newly assembled genome databases, a genome-wide analysis of apoptosis-related genes in Bombyx mori was performed using both nucleotide and protein Blast searches. Fifty-two apoptosis-related candidate genes were identified, including five caspase family members, two tumor necrosis factor (TNF) superfamily members, one Bcl-2 family member, four baculovirus IAP (inhibitor of apoptosis) repeat (BIR) domain family members and 1 RHG (Reaper, Hid, Grim, and Sickle; Drosophila cell death activators) family member. Moreover, we identified a new caspase family member, BmCaspase-New, two splice variants of BmDronc, and Bm3585, a mammalian TNF superfamily member homolog. Twenty-three of these apoptosis-related genes were cloned and sequenced using cDNA templates isolated from BmE-SWU1 cells. Sequence analyses revealed that these genes could have key roles in apoptosis. Conclusions Bombyx mori possesses potential apoptosis-related genes. We hypothesized that the classic intrinsic and extrinsic apoptotic pathways potentially are active in Bombyx mori. These results lay the foundation for further apoptosis-related study in Bombyx mori.

2010-01-01

427

Caveolin-1 abrogates TGF-? mediated hepatocyte apoptosis.  

PubMed

Transforming growth factor (TGF)-? has a dual role in liver, providing cytostatic effects during liver damage and regeneration, as well as carcinogenic functions in malignant transformation and hepatocellular cancer. In cultured hepatocytes, TGF-? can trigger apoptosis and epithelial-mesenchymal transition (EMT). Caveolin-1 is associated with progression of hepatocellular cancer and has been linked to TGF-? signaling. This study aimed at elucidating whether Caveolin-1 regulates TGF-? mediated hepatocyte fate. Knockdown of Caveolin-1 strongly reduced TGF-?