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1.
Fortschr Neurol Psychiatr ; 84 Suppl 1: S36-40, 2016 Jul.
Artigo em Alemão | MEDLINE | ID: mdl-27276071

RESUMO

Parkinson's disease is characterized by a continuous spectrum of varying severity. The treatment is driven by new and sometimes highly complex therapeutic procedures. These two aspects are responsible for the blurred dividing line between outpatient and inpatient care. The aim of this article is to define criteria that should help determine the indication for inpatient or outpatient treatment. We introduce quality requirements that have already been taken into account in part in therapy modalities such as Parkinson complex treatment. The decision on the appropriate form of care affects the medical freedom of therapy, which must reconcile the legitimate interest of patients to receive optimal care with the given economic conditions. Our aim is to provide guidance on decisions on the best form of treatment in the context of changing framework conditions in the health sector.


Assuntos
Assistência Ambulatorial , Pacientes Internados , Doença de Parkinson/terapia , Administração dos Cuidados ao Paciente , Hospitalização , Humanos
2.
Genes Immun ; 16(7): 462-9, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26247836

RESUMO

We previously described that sensitivity to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis varied in rheumatoid arthritis fibroblasts-like synoviocytes (RAFLS) from one patient to another and was correlated with disease severity. Therefore, we screened for genes differentially expressed in RAFLS sensitive and resistant to TRAIL-induced apoptosis. The sensitivity of RAFLS was defined based on the percentage of TRAIL-induced apoptosis: 0-10% for resistant cells and >25% for sensitive RAFLS. We performed transcriptomic comparison between RAFLS-S (n=6) and RAFLS-R (n=6) and then examined the implication of identified candidates in the regulation of apoptosis using small interference RNA (siRNA). Microarray analysis revealed 10 functional genes differentially expressed according to TRAIL sensitivity. These factors are implicated in different functions, such as the respiratory chain (ND3), the transport of lipids (OSBP2, PLTP), the regulation of signaling linked to extracellular factors (SULF2, GALNT1, SIAE) or the regulation of gene expression (TET2 and LARP6). We confirmed differential expression for GALNT1 and LARP6 by quantitative reverse transcriptase-PCR. Using siRNA extinction, we demonstrated the implication of GALNT1, SULF2 and LARP6 in the control of TRAIL-induced responses. These results are of particular interest as GALNT1 and LARP6 have been implicated in the regulation of cell death and may represent interesting targets to induce apoptosis of RAFLS.


Assuntos
Apoptose/genética , Artrite Reumatoide/genética , Artrite Reumatoide/patologia , Membrana Sinovial/patologia , Ligante Indutor de Apoptose Relacionado a TNF/genética , Adulto , Artrite Reumatoide/metabolismo , Proliferação de Células/fisiologia , Feminino , Fibroblastos/citologia , Fibroblastos/fisiologia , Perfilação da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , RNA Interferente Pequeno/genética , Transdução de Sinais , Membrana Sinovial/metabolismo
3.
J Chem Phys ; 143(7): 074705, 2015 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-26298146

RESUMO

The intermetallic compound InPd (CsCl type of crystal structure with a broad compositional range) is considered as a candidate catalyst for the steam reforming of methanol. Single crystals of this phase have been grown to study the structure of its three low-index surfaces under ultra-high vacuum conditions, using low energy electron diffraction (LEED), X-ray photoemission spectroscopy (XPS), and scanning tunneling microscopy (STM). During surface preparation, preferential sputtering leads to a depletion of In within the top few layers for all three surfaces. The near-surface regions remain slightly Pd-rich until annealing to ∼580 K. A transition occurs between 580 and 660 K where In segregates towards the surface and the near-surface regions become slightly In-rich above ∼660 K. This transition is accompanied by a sharpening of LEED patterns and formation of flat step-terrace morphology, as observed by STM. Several superstructures have been identified for the different surfaces associated with this process. Annealing to higher temperatures (≥750 K) leads to faceting via thermal etching as shown for the (110) surface, with a bulk In composition close to the In-rich limit of the existence domain of the cubic phase. The Pd-rich InPd(111) is found to be consistent with a Pd-terminated bulk truncation model as shown by dynamical LEED analysis while, after annealing at higher temperature, the In-rich InPd(111) is consistent with an In-terminated bulk truncation, in agreement with density functional theory (DFT) calculations of the relative surface energies. More complex surface structures are observed for the (100) surface. Additionally, individual grains of a polycrystalline sample are characterized by micro-spot XPS and LEED as well as low-energy electron microscopy. Results from both individual grains and "global" measurements are interpreted based on comparison to our single crystals findings, DFT calculations and previous literature.

4.
Nat Mater ; 11(8): 690-3, 2012 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-22683821

RESUMO

Replacing noble metals in heterogeneous catalysts by low-cost substitutes has driven scientific and industrial research for more than 100 years. Cheap and ubiquitous iron is especially desirable, because it does not bear potential health risks like, for example, nickel. To purify the ethylene feed for the production of polyethylene, the semi-hydrogenation of acetylene is applied (80 × 10(6) tons per annum; refs 1-3). The presence of small and separated transition-metal atom ensembles (so-called site-isolation), and the suppression of hydride formation are beneficial for the catalytic performance. Iron catalysts necessitate at least 50 bar and 100 °C for the hydrogenation of unsaturated C-C bonds, showing only limited selectivity towards semi-hydrogenation. Recent innovation in catalytic semi-hydrogenation is based on computational screening of substitutional alloys to identify promising metal combinations using scaling functions and the experimental realization of the site-isolation concept employing structurally well-ordered and in situ stable intermetallic compounds of Ga with Pd (refs 15-19). The stability enables a knowledge-based development by assigning the observed catalytic properties to the crystal and electronic structures of the intermetallic compounds. Following this approach, we identified the low-cost and environmentally benign intermetallic compound Al(13)Fe(4) as an active and selective semi-hydrogenation catalyst. This knowledge-based development might prove applicable to a wide range of heterogeneously catalysed reactions.

5.
Phys Rev Lett ; 110(7): 076102, 2013 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-25166385

RESUMO

We have investigated the structure of the Al(13)Fe(4)(010) surface using both experimental and ab initio computational methods. The results indicate that the topmost surface layers correspond to incomplete puckered (P) planes present in the bulk crystal structure. The main building block of the corrugated termination consists of two adjacent pentagons of Al atoms, each centered by a protruding Fe atom. These motifs are interconnected via additional Al atoms referred to as "glue" atoms which partially desorb above 873 K. The surface structure of lower atomic density compared to the bulk P plane is explained by a strong Fe-Al-Fe covalent polar interaction that preserves intact clusters at the surface. The proposed surface model with identified Fe-containing atomic ensembles could explain the Al(13)Fe(4) catalytic properties recently reported in line with the site-isolation concept [M. Armbrüster et al., Nat. Mater. 11, 690 (2012)].

6.
Z Rheumatol ; 71(1): 64-7, 2012 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-22143445

RESUMO

Chronic inflammatory diseases are characterized by hypoxia and subsequent cellular adaptation via hypoxia-inducible factor (HIF). Modulation of these adaptation mechanisms provides the basis for ideas on how to improve the effects of known drugs and for the development of novel therapeutic approaches.


Assuntos
Hipóxia Celular/imunologia , Imunidade Inata/imunologia , Inflamação/imunologia , Articulações/imunologia , Modelos Imunológicos , Doenças Reumáticas/imunologia , Animais , Humanos
7.
J Exp Med ; 181(6): 2283-7, 1995 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-7760014

RESUMO

Staphylococcal enterotoxin B (SEB) is a bacterial superantigen that binds to major histocompatibility complex class II molecules and selectively interacts with T cells that bear certain T cell receptor (TCR) V beta domains. Administration of SEB in adult mice results in initial proliferation of V beta 8+ T cells followed by a state of unresponsiveness resulting from a combination of clonal deletion and clonal anergy in the SEB-reactive population. At this time, it is unclear what relationship exists between the T cells that have proliferated and those that have been deleted or have become anergic. Here we show that only a fraction of the potentially reactive V beta 8+ T cells proliferate in response to SEB in vivo, and that all the cells that have proliferated eventually undergo apoptosis. Virtually no apoptosis can be detected in the nonproliferating V beta 8+ T cells. These data demonstrate a causal relationship between proliferation and apoptosis in response to SEB in vivo, and they further indicate that T cells bearing the same TCR V beta segment can respond differently to the same superantigen. The implications of this differential responsiveness in terms of activation and tolerance are discussed.


Assuntos
Apoptose , Enterotoxinas/farmacologia , Ativação Linfocitária , Superantígenos/farmacologia , Linfócitos T/fisiologia , Animais , Bromodesoxiuridina , Linfócitos T CD4-Positivos/fisiologia , Linfócitos T CD8-Positivos/fisiologia , Anergia Clonal , Citometria de Fluxo , Cinética , Ativação Linfocitária/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Staphylococcus aureus , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/imunologia , Linfócitos T/citologia
8.
J Exp Med ; 183(2): 431-7, 1996 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-8627156

RESUMO

Staphylococcal enterotoxin B (SEB) is a bacterial superantigen (SAg) that predominantly interacts with V(beta)8+ T cells. In vivo treatment of mice with SEB leads to an initial increase in the percentage of V(beta)8+ T cells, followed by a decrease in the numbers of these cells, eventually reaching lower levels than those found before treatment with the SAg. This decrease is due to apoptosis of the SEB-responding cells. In the present study, we use the distinct light scattering characteristics of apoptotic cells to characterize T cells that are being deleted in response to SEB in vivo. We show that dying, SEB-reactive T cells express high levels of Fas and Fas ligand (Fas-L), which are implicated in apoptotic cell death. In addition, the B cell marker B220 is upregulated on apoptotic cells. Moreover, we show that the generation of cells with an apoptotic phenotype is severely impaired in response to SEB in functional Fas-L-deficient mutant gld mice, confirming the role of the Fas pathway in SAg mediated peripheral deletion in vivo.


Assuntos
Apoptose , Enterotoxinas/imunologia , Regulação da Expressão Gênica no Desenvolvimento , Superantígenos/imunologia , Linfócitos T/imunologia , Animais , Linfócitos B/imunologia , Epitopos , Proteína Ligante Fas , Citometria de Fluxo , Antígenos Comuns de Leucócito/biossíntese , Glicoproteínas de Membrana/biossíntese , Camundongos , Camundongos Endogâmicos BALB C , Receptores de Antígenos de Linfócitos T alfa-beta/biossíntese , Espalhamento de Radiação , Subpopulações de Linfócitos T/imunologia , Regulação para Cima , Receptor fas/biossíntese
9.
J Exp Med ; 179(4): 1391-5, 1994 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-8145052

RESUMO

The integrin very late antigen, (VLA-4) alpha 4 beta 1 and its counter receptor vascular cell adhesion molecule 1 (VCAM-1) are involved in B cell maturation and pre-B cell attachment to bone marrow stroma cells. We have analyzed whether heat-stable antigen (HSA), a marker for immature leukocytes, is involved in such cell adhesion phenomena. HSA is a glycolipid-anchored, highly glycosylated surface protein differentially expressed on cells during the maturation of both the hematopoietic and nervous systems. We found that pre-B cells lacking HSA (due to targeted disruption of both alleles) can still bind via VLA-4 to tumor necrosis factor alpha-stimulated endothelioma cells. This binding, however, cannot be blocked by an anti-VCAM-1 antibody. Restoration of HSA expression restores the inhibitable VCAM-1 binding. We also found that pre-B cells lacking HSA did not bind to the FN40 fragment of fibronectin but reexpression of HSA restored VLA-4-mediated binding to fibronectin. Thus, expression of HSA on pre-B cells modifies the binding specificity of VLA-4 for two known ligands.


Assuntos
Antígenos CD/fisiologia , Linfócitos B/citologia , Adesão Celular/fisiologia , Glicoproteínas de Membrana , Receptores de Antígeno muito Tardio/fisiologia , Animais , Linfócitos B/imunologia , Antígeno CD24 , Adesão Celular/imunologia , Linhagem Celular Transformada , Endotélio/citologia , Fibronectinas/metabolismo , Humanos , Camundongos , Células Tumorais Cultivadas , Fator de Necrose Tumoral alfa/farmacologia
10.
J Exp Med ; 187(8): 1205-13, 1998 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-9547332

RESUMO

Human Fas ligand (L) (CD95L) and tumor necrosis factor (TNF)-alpha undergo metalloproteinase-mediated proteolytic processing in their extracellular domains resulting in the release of soluble trimeric ligands (soluble [s]FasL, sTNF-alpha) which, in the case of sFasL, is thought to be implicated in diseases such as hepatitis and AIDS. Here we show that the processing of sFasL occurs between Ser126 and Leu127. The apoptotic-inducing capacity of naturally processed sFasL was reduced by >1,000-fold compared with membrane-bound FasL, and injection of high doses of recombinant sFasL in mice did not induce liver failure. However, soluble FasL retained its capacity to interact with Fas, and restoration of its cytotoxic activity was achieved both in vitro and in vivo with the addition of cross-linking antibodies. Similarly, the marginal apoptotic activity of recombinant soluble TNF-related apoptosis-inducing ligand (sTRAIL), another member of the TNF ligand family, was greatly increased upon cross-linking. These results indicate that the mere trimerization of the Fas and TRAIL receptors may not be sufficient to trigger death signals. Thus, the observation that sFasL is less cytotoxic than membrane-bound FasL may explain why in certain types of cancer, systemic tissue damage is not detected, even though the levels of circulating sFasL are high.


Assuntos
Apoptose , Fígado/patologia , Glicoproteínas de Membrana/metabolismo , Processamento de Proteína Pós-Traducional , Sequência de Aminoácidos , Animais , Regulação para Baixo , Proteína Ligante Fas , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Modelos Biológicos , Dados de Sequência Molecular , Ligação Proteica , Receptores do Fator de Necrose Tumoral/metabolismo , Solubilidade , Fator de Necrose Tumoral alfa/metabolismo
11.
J Exp Med ; 188(6): 1185-90, 1998 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-9743536

RESUMO

Members of the tumor necrosis factor (TNF) family induce pleiotropic biological responses, including cell growth, differentiation, and even death. Here we describe a novel member of the TNF family designated APRIL (for a proliferation-inducing ligand). Although transcripts of APRIL are of low abundance in normal tissues, high levels of mRNA are detected in transformed cell lines, and in human cancers of colon, thyroid, and lymphoid tissues in vivo. The addition of recombinant APRIL to various tumor cells stimulates their proliferation. Moreover, APRIL-transfected NIH-3T3 cells show an increased rate of tumor growth in nude mice compared with the parental cell line. These findings suggest that APRIL may be implicated in the regulation of tumor cell growth.


Assuntos
Substâncias de Crescimento/fisiologia , Proteínas de Membrana/fisiologia , Células Tumorais Cultivadas/patologia , Fator de Necrose Tumoral alfa/fisiologia , Células 3T3 , Sequência de Aminoácidos , Animais , Divisão Celular/efeitos dos fármacos , Humanos , Ligantes , Linfoma de Células B , Proteínas de Membrana/biossíntese , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Dados de Sequência Molecular , Transplante de Neoplasias , RNA Mensageiro/biossíntese , Transfecção , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismo , Membro 13 da Superfamília de Ligantes de Fatores de Necrose Tumoral
12.
J Exp Med ; 189(5): 779-86, 1999 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-10049941

RESUMO

Contact hypersensitivity (CHS) is a T cell-mediated skin inflammation induced by epicutaneous exposure to haptens in sensitized individuals. We have previously reported that CHS to dinitrofluorobenzene in mice is mediated by major histocompatibility complex (MHC) class I-restricted CD8(+) T cells. In this study, we show that CD8(+) T cells mediate the skin inflammation through their cytotoxic activity. The contribution of specific cytotoxic T lymphocytes (CTLs) to the CHS reaction was examined both in vivo and in vitro, using mice deficient in perforin and/or Fas/Fas ligand (FasL) pathways involved in cytotoxicity. Mice double deficient in perforin and FasL were able to develop hapten-specific CD8(+) T cells in the lymphoid organs but did not show CHS reaction. However, they did not generate hapten-specific CTLs, demonstrating that the CHS reaction is dependent on cytotoxic activity. In contrast, Fas-deficient lpr mice, FasL-deficient gld mice, and perforin-deficient mice developed a normal CHS reaction and were able to generate hapten-specific CTLs, suggesting that CHS requires either the Fas/FasL or the perforin pathway. This was confirmed by in vitro studies showing that the hapten-specific CTL activity was exclusively mediated by MHC class I-restricted CD8(+) T cells which could use either the perforin or the Fas/FasL pathway for their lytic activity. Thus, cytotoxic CD8(+) T cells, commonly implicated in the host defence against tumors and viral infections, could also mediate harmful delayed-type hypersensitivity reactions.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Citotoxicidade Imunológica , Dermatite de Contato/imunologia , Animais , Movimento Celular , Dermatite de Contato/etiologia , Dermatite de Contato/genética , Dinitrofluorbenzeno/imunologia , Proteína Ligante Fas , Haptenos , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Interferon gama/biossíntese , Tecido Linfoide/imunologia , Glicoproteínas de Membrana/deficiência , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Perforina , Proteínas Citotóxicas Formadoras de Poros , Pele/imunologia , Receptor fas/genética
13.
Ann Rheum Dis ; 68(6): 997-1002, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18676986

RESUMO

OBJECTIVE: To determine whether serum levels of a proliferation-inducing ligand (APRIL) are altered in patients with systemic lupus erythematosus (SLE), and correlate with disease parameters. METHODS: Clinical and biological parameters were analysed for 43 patients that fulfilled American College of Rheumatology (ACR) criteria for SLE classification and were positive for anti-double-stranded DNA (dsDNA) antibodies at least once in their medical records. Tests included measurement of serum levels of the tumour necrosis factor (TNF) family members APRIL and B lymphocyte stimulator (BLyS; a cytokine shown to promote SLE disease). RESULTS: Median APRIL levels were elevated in patients with SLE compared to patients with osteoarthritis and healthy controls, but did not correlate with the SLE Disease Activity Index (SLEDAI). APRIL serum levels showed an inverse correlation with BLyS serum levels (r = -0.339; p = 0.03). For patients with SLE with positive anti-dsDNA titres (>40 arbitrary units (AU)/ml) at inclusion (n = 25), circulating APRIL was inversely correlated with BLyS levels (r = -0.465; p = 0.022) and anti-dsDNA antibody titres (r = -0.411; p = 0.046). In a follow-up study at their second visit, 27 patients showed an inverse correlation of APRIL serum levels with BLyS (r = -0.398; p = 0.03) as well as with anti-dsDNA (r = -0.408; p = 0.03) titres and SLEDAI (r = -0.408; p = 0.01). CONCLUSION: The inverse correlation observed between APRIL and BLyS suggests that APRIL acts as a protective factor. APRIL and BLyS may thus have opposite roles in SLE, which must be considered when defining therapeutic applications of these cytokines.


Assuntos
Fator Ativador de Células B/sangue , Lúpus Eritematoso Sistêmico/sangue , Membro 13 da Superfamília de Ligantes de Fatores de Necrose Tumoral/sangue , Doença Aguda , Adulto , Anticorpos Antinucleares/sangue , Autoanticorpos/sangue , Estudos de Casos e Controles , DNA/imunologia , Feminino , Seguimentos , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Masculino , Pessoa de Meia-Idade , Estatísticas não Paramétricas , Adulto Jovem
14.
J Cell Biol ; 121(3): 655-64, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-7683689

RESUMO

We have distinguished five TNF-alpha-inducible cell adhesion mechanisms on microvasculature-derived endothelioma cells of the mouse which mediate the binding of different types of leukocytes. Three of these mechanisms could be identified as the mouse homologs of ICAM-1, VCAM-1, and E-selectin, of which the latter was defined by the novel mAb 21KC10. The fourth TNF-alpha-inducible cell adhesion mechanism was blocked by antibodies specific for mouse P-selectin. We have recently shown that TNF-alpha stimulates the synthesis of P-selectin in mouse endothelioma cells (A. Weller, S. Isenmann, D. Vestweber. 1992. J. Biol. Chem. 267:15176-15183). Here we show that this stimulation leads to maximal cell surface expression levels within 4 h after stimulation while the same endothelioma cells are also able to upregulate P-selectin at the cell surface within minutes after stimulation with PMA. Both effects are additive. The fifth TNF-induced cell adhesion mechanism is defined by mediating the binding to the mouse monocyte/macrophage cell line J774. This adhesion mechanism is not inhibited by antibodies against any of the other four CAMs; it functions well at 7 degrees C (in contrast to ICAM-1 and VCAM-1) and it is as active after 16 h of TNF induction as after 4 h (in contrast to E- and P-selectin). Furthermore, this new adhesion mechanism only functions on two of three endothelioma cell lines and is undetectable on the third, although ICAM-1, VCAM-1, E-selectin, and P-selectin could be demonstrated to function well on this cell line. Thus, in addition to the three known TNF-inducible CAMs, ICAM-1, VCAM-1, and E-selectin, also P-selectin and a fifth, as yet molecularly undefined cell adhesion mechanism, are TNF inducible at the cell surface of mouse endothelioma cells.


Assuntos
Adesão Celular/efeitos dos fármacos , Fator de Necrose Tumoral alfa/farmacologia , Animais , Anticorpos Monoclonais/farmacologia , Moléculas de Adesão Celular/metabolismo , Linhagem Celular , Selectina E , Humanos , Molécula 1 de Adesão Intercelular , Cinética , Leucócitos/metabolismo , Macrófagos , Camundongos , Monócitos , Selectina-P , Glicoproteínas da Membrana de Plaquetas/antagonistas & inibidores , Células Tumorais Cultivadas/efeitos dos fármacos , Molécula 1 de Adesão de Célula Vascular
15.
J Cell Biol ; 133(2): 335-43, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8609166

RESUMO

The cell surface receptor Fas (FasR, Apo-1, CD95) and its ligand (FasL) are mediators of apoptosis that have been shown to be implicated in the peripheral deletion of autoimmune cells, activation-induced T cell death, and one of the two major cytolytic pathways mediated by CD8+ cytolytic T cells. To gain further understanding of the Fas system., we have analyzed Fas and FasL expression during mouse development and in adult tissues. In developing mouse embryos, from 16.5 d onwards, Fas mRNA is detectable in distinct cell types of the developing sinus, thymus, lung, and liver, whereas FasL expression is restricted to submaxillary gland epithelial cells and the developing nervous system. Significant Fas and FasL expression were observed in several nonlymphoid cell types during embryogenesis, and generally Fas and FasL expression were not localized to characteristic sites of programmed cell death. In the adult mouse, RNase protection analysis revealed very wide expression of both Fas and FasL. Several tissues, including the thymus, lung, spleen, small intestine, large intestine, seminal vesicle, prostate, and uterus, clearly coexpress the two genes. Most tissues constitutively coexpressing Fas and FasL in the adult mouse are characterized by apoptotic cell turnover, and many of those expressing FasL are known to be immune privileged. It may be, therefore, that the Fas system is implicated in both the regulation of physiological cell turnover and the protection of particular tissues against potential lymphocyte-mediated damage.


Assuntos
Apoptose/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Glicoproteínas de Membrana/genética , Receptor fas/genética , Animais , Sequência de Bases , Desenvolvimento Embrionário e Fetal , Proteína Ligante Fas , Feminino , Masculino , Glicoproteínas de Membrana/análise , Camundongos , Dados de Sequência Molecular , Especificidade de Órgãos , RNA Mensageiro/análise , Testículo/química , Receptor fas/análise
16.
Science ; 274(5291): 1363-6, 1996 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-8910274

RESUMO

Malignant melanoma accounts for most of the increasing mortality from skin cancer. Melanoma cells were found to express Fas (also called Apo-1 or CD95) ligand (FasL). In metastatic lesions, Fas-expressing T cell infiltrates were proximal to FasL+ tumor cells. In vitro, apoptosis of Fas-sensitive target cells occurred upon incubation with melanoma tumor cells; and in vivo, injection of FasL+ mouse melanoma cells in mice led to rapid tumor formation. In contrast, tumorigenesis was delayed in Fas-deficient lpr mutant mice in which immune effector cells cannot be killed by FasL. Thus, FasL may contribute to the immune privilege of tumors.


Assuntos
Apoptose , Melanoma/imunologia , Glicoproteínas de Membrana/fisiologia , Linfócitos T Citotóxicos/citologia , Evasão Tumoral , Receptor fas/fisiologia , Animais , Proteína Ligante Fas , Humanos , Ligantes , Linfócitos do Interstício Tumoral/citologia , Linfócitos do Interstício Tumoral/imunologia , Melanoma/metabolismo , Melanoma/patologia , Melanoma/secundário , Glicoproteínas de Membrana/análise , Glicoproteínas de Membrana/biossíntese , Camundongos , Camundongos Endogâmicos C57BL , Linfócitos T Citotóxicos/imunologia , Células Tumorais Cultivadas , Receptor fas/biossíntese
17.
Science ; 292(5524): 2037-41, 2001 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-11358995

RESUMO

Self-amplified spontaneous emission in a free-electron laser has been proposed for the generation of very high brightness coherent x-rays. This process involves passing a high-energy, high-charge, short-pulse, low-energy-spread, and low-emittance electron beam through the periodic magnetic field of a long series of high-quality undulator magnets. The radiation produced grows exponentially in intensity until it reaches a saturation point. We report on the demonstration of self-amplified spontaneous emission gain, exponential growth, and saturation at visible (530 nanometers) and ultraviolet (385 nanometers) wavelengths. Good agreement between theory and simulation indicates that scaling to much shorter wavelengths may be possible. These results confirm the physics behind the self-amplified spontaneous emission process and forward the development of an operational x-ray free-electron laser.

18.
Curr Biol ; 10(11): 640-8, 2000 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-10837247

RESUMO

BACKGROUND: Activation of Fas (CD95) by its ligand (FasL) rapidly induces cell death through recruitment and activation of caspase-8 via the adaptor protein Fas-associated death domain protein (FADD). However, Fas signals do not always result in apoptosis but can also trigger a pathway that leads to proliferation. We investigated the level at which the two conflicting Fas signals diverge and the protein(s) that are implicated in switching the response. RESULTS: Under conditions in which proliferation of CD3-activated human T lymphocytes is increased by recombinant FasL, there was activation of the transcription factors NF-kappaB and AP-1 and recruitment of the caspase-8 inhibitor and FADD-interacting protein FLIP (FLICE-like inhibitory protein). Fas-recruited FLIP interacts with TNF-receptor associated factors 1 and 2, as well as with the kinases RIP and Raf-1, resulting in the activation of the NF-kappaB and extracellular signal regulated kinase (Erk) signaling pathways. In T cells these two signal pathways are critical for interleukin-2 production. Increased expression of FLIP in T cells resulted in increased production of interleukin-2. CONCLUSIONS: We provide evidence that FLIP is not simply an inhibitor of death-receptor-induced apoptosis but that it also mediates the activation of NF-kappaB and Erk by virtue of its capacity to recruit adaptor proteins involved in these signaling pathways.


Assuntos
Proteínas de Transporte/metabolismo , Inibidores de Caspase , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NF-kappa B/metabolismo , Transdução de Sinais/fisiologia , Linfócitos T/fisiologia , Apoptose , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD , Complexo CD3/fisiologia , Caspase 8 , Caspase 9 , Células Cultivadas , Proteína Ligante Fas , Humanos , Interleucina-2/biossíntese , Glicoproteínas de Membrana/farmacologia , Proteínas/metabolismo , Proteínas Proto-Oncogênicas c-raf , Proteína Serina-Treonina Quinases de Interação com Receptores , Receptores do Fator de Necrose Tumoral/fisiologia , Transdução de Sinais/efeitos dos fármacos , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Fator 1 Associado a Receptor de TNF , Fator 2 Associado a Receptor de TNF , Fator de Transcrição AP-1/metabolismo , Receptor fas/fisiologia
19.
J Clin Invest ; 97(2): 316-22, 1996 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-8567950

RESUMO

The expression and function of Fas (CD95/APO-1), a cell surface receptor directly responsible for triggering cell death by apoptosis, was investigated on human T lymphocytes resident within the intestinal lamina propria, a major site of antigen challenge and persistent lymphocyte activation. Three color immunofluorescence and FACS analysis indicated that virtually all freshly isolated human gut lamina propria T lymphocytes (T-LPL) express Fas, together with the marker of progress activation CD45R0. A discrete fraction of freshly isolated T-LPL also constitutively expressed Fas ligand (FasL), perhaps as a result of recent in vivo activation. Importantly, whereas Fas cross-linking did not result in apoptosis induction in peripheral blood T lymphocytes (T-PBL), Fas was found to be fully effective in generating the apoptotic signal in T-LPL. This was associated with the activation of an acidic sphingomyelinase and with ceramide generation, early events known to be involved in Fas-mediated apoptotic signaling. By contrast, acidic sphingomyelinase activation and ceramide production were not detectable in T-PBL after Fas cross-linking. However C2-ceramide, a cell permeant synthetic analog of ceramide, could efficiently induce apoptosis in T-LPL and T-PBL when added exogenously. These data indicate that T-LPL constitutively express both Fas and FasL and that Fas cross-linking generates signals resulting in sphingomyelin hydrolysis and apoptosis, outlining a potential mechanism involved in intestinal tolerance. Moreover, they provide the first evidence of a role for ceramide-mediated pathways in normal immunoregulation.


Assuntos
Imunidade nas Mucosas , Mucosa Intestinal/imunologia , Glicoproteínas de Membrana/metabolismo , Esfingomielina Fosfodiesterase/fisiologia , Linfócitos T/metabolismo , Receptor fas/metabolismo , Apoptose , Ceramidas/farmacologia , Proteína Ligante Fas , Citometria de Fluxo , Humanos , Mucosa Intestinal/citologia , Antígenos Comuns de Leucócito/metabolismo , Esfingomielinas/metabolismo
20.
J Clin Invest ; 99(6): 1173-8, 1997 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-9077524

RESUMO

Astrocytomas are among the most common brain tumors that are usually fatal in their malignant form. They appear to progress without significant impedance from the immune system, despite the presence of intratumoral T cell infiltration. To date, this has been thought to be the result of T cell immunosuppression induced by astrocytoma-derived cytokines. Here, we propose that cell contact-mediated events also play a role, since we demonstrate the in vivo expression of Fas ligand (FasL/CD95L) by human astrocytoma and the efficient killing of Fas-bearing cells by astrocytoma lines in vitro and by tumor cells ex vivo. Functional FasL is expressed by human, mouse, and rat astrocytoma and hence may be a general feature of this nonlymphoid tumor. In the brain, astrocytoma cells can potentially deliver a death signal to Fas+ cells which include infiltrating leukocytes and, paradoxically, astrocytoma cells themselves. The expression of FasL by astrocytoma cells may extend the processes that are postulated to occur in normal brain to maintain immune privilege, since we also show FasL expression by neurons. Overall, our findings suggest that FasL-induced apoptosis by astrocytoma cells may play a significant role in both immunosuppression and the regulation of tumor growth within the central nervous system.


Assuntos
Astrocitoma/imunologia , Neoplasias Encefálicas/imunologia , Encéfalo/imunologia , Glicoproteínas de Membrana/biossíntese , Receptor fas/metabolismo , Animais , Astrocitoma/metabolismo , Astrocitoma/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Testes Imunológicos de Citotoxicidade , Proteína Ligante Fas , Humanos , Ligantes , Glicoproteínas de Membrana/fisiologia , Camundongos , Ratos , Células Tumorais Cultivadas
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