77 resultados para bystander


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Excessively high, accelerating lung cancer rates among women in Harris County, Texas, prompted this case-comparison study. Objectives were to compare patterns of employment, indirect exposures, and sociodemographic variables of lung cancer cases with comparison subjects (compeers) after standardizing for possible confounders, such as age and cigarette smoking. Lung cancer cases were microscopically confirmed, white, Harris County residents. Compeers, chosen from Medicare records and Texas Department of Public Safety records, were matched on gender, race, age, resident and vital status. Personal interviews were conducted with study subjects or next-of-kin. Industries and occupations were categorized as high risk, based on previous studies.^ Almost all cases (95.0%) and 60.0% of compeers smoked cigarettes. The odds ratio for lung cancer and smoking is 13.9. Stopping smoking between ages 30-50 years carries a lower risk than stopping at age 58 or more years. Women's employment in a high risk industry or occupation results in consistently elevated, smoking-adjusted odds ratios. Frequency and duration of employment demonstrate a moderate dose-response effect. A temporal association exists with employment in a high risk occupation during 1940-1949.^ No increased risk appeared with passive smoking. Husband's employment in a construction industry or a structural occupation significantly increased the smoking-adjusted odds ratios among cases and compeers (O.R. = 2.9, 2.2). Smoking-adjusted odds ratios increased significantly when women had resided with persons employed in cement (O.R. = 3.2) or insulation (O.R. = 5.5) manufacturing, or a high rise construction industry (O.R. = 2.4). A family history of lung cancer resulted in a two-fold increase in smoking-adjusted odds ratios. Vital status of compeers affected the odds ratios.^ Work-related exposures appear to increase the risk of lung cancer in women although cigarette smoking has the single highest odds ratio. Indirect exposure to certain employment also plays a significant role in lung cancer in women. Investigations of specific direct and indirect hazardous exposures in the workplace and home are needed. Cigarette smoking is as hazardous for women as for men. Smoking should be prevented and eliminated. ^

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Experimental autoimmune encephalomyelitis (EAE) induced with myelin proteolipid protein (PLP) residues 139–151 (HSLGKWLGHPDKF) can be prevented by treatment with a T cell receptor (TCR) antagonist peptide (L144/R147) generated by substituting at the two principal TCR contact residues in the encephalitogenic peptide. The TCR antagonist peptide blocks activation of encephalitogenic Th1 helper cells in vitro, but the mechanisms by which the antagonist peptide blocks EAE in vivo are not clear. Immunization with L144/R147 did not inhibit generation of PLP-(139–151)-specific T cells in vivo. Furthermore, preimmunization with L144/R147 protected mice from EAE induced with the encephalitogenic peptides PLP-(178–191) and myelin oligodendrocyte protein (MOG) residues 92–106 and with mouse myelin basic protein (MBP). These data suggest that the L144/R147 peptide does not act as an antagonist in vivo but mediates bystander suppression, probably by the generation of regulatory T cells. To confirm this we generated T cell lines and clones from animals immunized with PLP-(139–151) plus L144/R147. T cells specific for L144/R147 peptide were crossreactive with the native PLP-(139–151) peptide, produced Th2/Th0 cytokines, and suppressed EAE upon adoptive transfer. These studies demonstrate that TCR antagonist peptides may have multiple biological effects in vivo. One of the principal mechanisms by which these peptides inhibit autoimmunity is by the induction of regulatory T cells, leading to bystander suppression of EAE. These results have important implications for the treatment of autoimmune diseases where there are autopathogenic responses to multiple antigens in the target organ.

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In gene therapy to treat cancer, typically only a fraction of the tumor cells can be successfully transfected with a gene. However, in the case of brain tumor therapy with the thymidine kinase gene from herpes simplex virus (HSV-tk), not only the cells transfected with the gene but also neighboring others can be killed in the presence of ganciclovir. Such a "bystander" effect is reminiscent of our previous observation that the effect of certain therapeutic agents may be enhanced by their diffusion through gap junctional intercellular communication (GJIC). Herein, we present the evidence, from in vitro studies, that gap junctions could indeed be responsible for such a gene therapy bystander effect. We used HeLa cells for this purpose, since they show very little, if any, ability to communicate through gap junctions. When HeLa cells were transfected with HSV-tk gene and cocultured with nontransfected cells, only HSV-tk-transfected HeLa cells (tk+) were killed by ganciclovir. However, when HeLa cells transfected with a gene encoding for the gap junction protein, connexin 43 (Cx43), were used, not only tk+ cells, but also tk- cells were killed, presumably due to the transfer, via Cx43-mediated GJIC, of toxic ganciclovir molecules phosphorylated by HSV-tk to the tk- cells. Such bystander effect was not observed when tk+ and tk- cells were cocultured without direct cell-cell contact between those two types of cells. Thus, our results give strong evidence that the bystander effect seen in HSV-tk gene therapy may be due to Cx-mediated GJIC.

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Herpes simplex virus thymidine kinase (HSV-tk)/ganciclovir (GCV) viral-directed enzyme prodrug gene therapy causes potent, tumor-selective cytotoxicity in animal models in which HSV-tk gene transduction is limited to a minority of tumor cells. The passage of toxic molecules from HSV-tk+ cells to neighboring HSV-tk- cells during GCV therapy is one mechanism that may account for this "bystander" cytotoxicity. To investigate whether gap junction-mediated intercellular coupling could mediate this bystander effect, we used a flow cytometry assay to quantitate the extent of heterocellular coupling between HSV-tk+ murine fibroblasts and both rodent and human tumor cell lines. Bystander tumor cytotoxicity during GCV treatment in a coculture assay was highly correlated (P < 0.001) with the extent of gap junction-mediated coupling. These findings show that gap junction-mediated intercellular coupling contributes to the in vitro bystander effect during HSV-tk/GCV therapy and that retroviral transduction of tumor cells is not required for bystander cytotoxicity.

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General note: Title and date provided by Bettye Lane.

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This study aims to determine whether the British Heart Foundation (BHF) PocketCPR application can improve the depth and rate of chest compression, and therefore be confidently recommended for bystander use. 118 candidates were recruited into a randomised crossover manikin trial. Each candidate performed CPR for two-minutes without instruction, or performed chest compressions using the PocketCPR application. Candidates then performed a further two minutes of CPR within the opposite arm. The number of chest compressions performed improved when PocketCPR was used compared to chest compressions when it was not (44.28% v40.57, P<0.001). The number of chest compressions performed to the required depth was higher in the PocketCPR group (90.86 v 66.26). The BHF PocketCPR application improved the percentage of chest compressions that were performed to the required depth. Despite this, more work is required in order to develop a feedback device that can improve bystander CPR without creating delay.

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Immunity induced by the 19-kDa fragment of merozoite surface protein 1 is dependent on CD4(+) Th cells. However, we found that adoptively transferred CFSE-labeled Th cells specific for an epitope on Plasmodium yoelii 19-kDa fragment of merozoite surface protein 1 (peptide (p)24), but not OVA-specific T cells, were deleted as a result of P. yoelii infection. As a result of infection, spleen cells recovered from infected p24-specific T cell-transfused mice demonstrated reduced response to specific Ag. A higher percentage of CFSE-labeled p24-specific T cells stained positive with annexin and anti-active caspase-3 in infected compared with uninfected mice, suggesting that apoptosis contributed to deletion of p24-specific T cells during infection. Apoptosis correlated with increased percentages of p24-specific T cells that stained positive for Fas from infected mice, suggesting that P. yoelii-induced apoptosis is, at least in part, mediated by Fas. However, bystander cells of other specificities also showed increased Fas expression during infection, suggesting that Fas expression alone is not sufficient for apoptosis. These data have implications for the development of immunity in the face of endemic parasite exposure.

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Members of the community contribute to survival from out-of-hospital cardiac arrest by contacting emergency medical services and performing cardiopulmonary resuscitation (CPR) prior to the arrival of an ambulance. In Australia there is a paucity of information of the extent that community members know the emergency telephone number and are trained in CPR. A survey of Queensland adults (n = 4490) was conducted to ascertain current knowledge and training levels and to target CPR training. Although most respondents (88.3%) could state the Australian emergency telephone number correctly, significant age differences were apparent (P < 0.001). One in five respondents aged 60 years and older could not state the emergency number correctly. While just over half the respondents (53.9%) had completed some form of CPR training, only 12.1% had recent training. Older people were more likely to have never had CPR training than young adults. Additional demographic and socio-economic differences were found between those never trained in CPR and those who were. The results emphasise the need to increase CPR training in those aged 40 and over, particularly females, and to increase the awareness of the emergency telephone number amongst older people. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

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The objectives of this study are to (1) quantify prior cardiopulmonary resuscitation (CPR) training in households of patients presenting to the Emergency Department (ED) with or without chest pain or ischaemic heart disease (IHD); (2) evaluate the willingness of household members to undertake CPR training; and (3) identify potential barriers to the learning and provision of bystander CPR. A cross-sectional study was conducted by surveying patients presenting to the ED of a metropolitan teaching hospital over a 6-month period. Two in five households of patients presenting with chest pain or IHD had prior training in CPR. This was no higher than for households of patients presenting without chest pain or IHD. Just under two in three households of patients presenting with chest pain or IHD were willing to participate in future CPR classes. Potential barriers to learning CPR included lack of information on CPR classes, perceived lack of intellectual and/or physical capability to learn CPR and concern about causing anxiety in the person at risk of cardiac arrest. Potential barriers to CPR provision included an unknown cardiac arrest victim and fear of infection. The ED provides an opportunity for increasing family and community capacity for bystander intervention through referral to appropriate training. (C) 2003 Published by Elsevier Science Ireland Ltd.

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The behavior of the Schistosoma mansoni infection in patients with AIDS has not been explored. The case of a young woman with schistosomiasis mansoni, AIDS, and cytomegalovirus disease is reported. The authors suggest that the helminth was not a bystander in this case, or rather, by interfering with the host's immune response, it set the stage for the development and/or aggravation of the viral infection.

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OBJECTIVE: To study electrophysiological characteristics that enable the identification and ablation of sites of chagasic tachycardia. METHODS: Thirty-one patients with chronic Chagas' heart disease and sustained ventricular tachycardia (SVT) underwent electrophysiological study to map and ablate that arrhythmia. Fifteen patients had hemodinamically stable SVT reproducible by programmed ventricular stimulation, 9 men and 6 women with ages ranging from 37 to 67 years and ejection fraction varying from 0.17 to 0.64. Endocardial mapping was performed during SVT in all patients. Radiofrequency (RF) current was applied to sites of presystolic activity of at least 30 ms. Entrainment was used to identify reentrant circuits. In both successful and unsuccessful sites of RF current application, electrogram and entrainment were analyzed. RESULTS: Entrainment was obtained during all mapped SVT. In 70.5% of the sites we observed concealed entrainment and ventricular tachycardia termination in the first 15 seconds of RF current application. In the unsuccessful sites, significantly earlier electrical activity was seen than in the successful ones. Concealed entrainment was significantly associated with ventricular tachycardia termination. Bystander areas were not observed. CONCLUSION: The reentrant mechanism was responsible for the genesis of all tachycardias. In 70.5% of the studied sites, the endocardial participation of the slow conducting zone of reentrant circuits was shown. Concealed entrainment was the main electrophysiological parameter associated with successful RF current application. There was no electrophysiological evidence of bystander regions in the mapped circuits of SVT.

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Les thérapies du cancer, comme la radiothérapie et la chimiothérapie, sont couramment utilisées mais ont de nombreux effets secondaires. Ces thérapies invasives pour le patient nécessitent d'être améliorées et de nombreuses avancées ont été faites afin d'adapter et de personnaliser le traitement du cancer. L'immunothérapie a pour but de renforcer le système immunitaire du patient et de le rediriger de manière spécifique contre la tumeur. Dans notre projet, nous activons les lymphocytes Invariant Natural Killer T (iNKT) afin de mettre en place une immunothérapie innovatrice contre le cancer. Les cellules iNKT sont une unique sous-population de lymphocytes T qui ont la particularité de réunir les propriétés de l'immunité innée ainsi qu'adaptative. En effet, les cellules iNKT expriment à leur surface des molécules présentes aussi sur les cellules tueuses NK, caractéristique de l'immunité innée, ainsi qu'un récepteur de cellules T (TCR) qui représente l'immunité adaptative. Les cellules iNKT reconnaissent avec leur TCR des antigènes présentés par la molécule CD1d. Les antigènes sont des protéines, des polysaccharides ou des lipides reconnus par les cellules du système immunitaire ou les anticorps pour engendrer une réponse immunitaire. Dans le cas des cellules iNKT, l'alpha-galactosylceramide (αGC) est un antigène lipidique fréquemment utilisé dans les études cliniques comme puissant activateur. Après l'activation des cellules iNKT avec l'αGC, celles-ci produisent abondamment et rapidement des cytokines. Ces cytokines sont des molécules agissant comme des signaux activateurs d'autres cellules du système immunitaire telles que les cellules NK et les lymphocytes T. Cependant, les cellules iNKT deviennent anergiques après un seul traitement avec l'αGC c'est à dire qu'elles ne peuvent plus être réactivées, ce qui limite leur utilisation dans l'immunothérapie du cancer. Dans notre groupe, Stirnemann et al ont publié une molécule recombinante innovante, composée de la molécule CD1d soluble et chargée avec le ligand αGC (αGC/sCD1d). Cette protéine est capable d'activer les cellules iNKT tout en évitant l'anergie. Dans le système immunitaire, les anticorps sont indispensables pour combattre une infection bactérienne ou virale. En effet, les anticorps ont la capacité de reconnaître et lier spécifiquement un antigène et permettent l'élimination de la cellule qui exprime cet antigène. Dans le domaine de l'immunothérapie, les anticorps sont utilisés afin de cibler des antigènes présentés seulement par la tumeur. Ce procédé permet de réduire efficacement les effets secondaires lors du traitement du cancer. Nous avons donc fusionné la protéine recombinante αGC/CD1d à un fragment d'anticorps qui reconnaît un antigène spécifique des cellules tumorales. Dans une étude préclinique, nous avons démontré que la protéine αGC/sCD1d avec un fragment d'anticorps dirigé contre la tumeur engendre une meilleure activation des cellules iNKT et entraîne un effet anti-tumeur prolongé. Cet effet anti-tumeur est augmenté comparé à une protéine αGC/CD1d qui ne cible pas la tumeur. Nous avons aussi montré que l'activation des cellules iNKT avec la protéine αGC/sCD1d-anti-tumeur améliore l'effet anti- tumoral d'un vaccin pour le cancer. Lors d'expériences in vitro, la protéine αGC/sCD1d-anti- tumeur permet aussi d'activer les cellules humaines iNKT et ainsi tuer spécifiquement les cellules tumorales humaines. La protéine αGC/sCD1d-anti-tumeur représente une alternative thérapeutique prometteuse dans l'immunothérapie du cancer. - Les cellules Invariant Natural Killer T (iNKT), dont les effets anti-tumoraux ont été démontrés, sont de puissants activateurs des cellules Natural Killer (NK), des cellules dendritiques (DC) et des lymphocytes T. Cependant, une seule injection du ligand de haute affinité alpha-galactosylceramide (αGC) n'induit une forte activation des cellules iNKT que durant une courte période. Celle-ci est alors suivie d'une longue phase d'anergie, limitant ainsi leur utilisation pour la thérapie. Comme alternative prometteuse, nous avons montré que des injections répétées d'αGC chargé sur une protéine recombinante de CD1d soluble (αGC/sCD1d) chez la souris entraînent une activation prolongée des cellules iNKT, associée à une production continue de cytokine. De plus, le maintien de la réactivité des cellules iNKT permet de prolonger l'activité anti-tumorale lorsque la protéine αGC/sCD1d est fusionnée à un fragment d'anticorps (scFv) dirigé contre la tumeur. L'inhibition de la croissance tumorale n'est optimale que lorsque les souris sont traitées avec la protéine αGC/sCD1d-scFv ciblant la tumeur, la protéine αGC/sCD1d-scFv non-appropriée étant moins efficace. Dans le système humain, les protéines recombinantes αGC/sCD1d-anti-HER2 et anti-CEA sont capables d'activer et de faire proliférer des cellules iNKT à partir de PBMCs issues de donneurs sains. De plus, la protéine αGC/sCD1d-scFv a la capacité d'activer directement des clones iNKT humains en l'absence de cellules présentatrices d'antigènes (CPA), contrairement au ligand αGC libre. Mais surtout, la lyse des cellules tumorales par les iNKT humaines n'est obtenue que lorsqu'elles sont incubées avec la protéine αGC/sCD1d-scFv anti- tumeur. En outre, la redirection de la cytotoxicité des cellules iNKT vers la tumeur est supérieure à celle obtenue avec une stimulation par des CPA chargées avec l'αGC. Afin d'augmenter les effets anti-tumoraux, nous avons exploité la capacité des cellules iNKT à activer l'immunité adaptive. Pour ce faire, nous avons combiné l'immunothérapie NKT/CD1d avec un vaccin anti-tumoral composé d'un peptide OVA. Des effets synergiques ont été obtenus lorsque les traitements avec la protéine αGC/sCD1d-anti-HER2 étaient associés avec le CpG ODN comme adjuvant pour la vaccination avec le peptide OVA. Ces effets ont été observés à travers l'activation de nombreux lymphocytes T CD8+ spécifique de la tumeur, ainsi que par la forte expansion des cellules NK. Les réponses, innée et adaptive, élevées après le traitement avec la protéine αGC/sCD1d-anti-HER2 combinée au vaccin OVA/CpG ODN étaient associées à un fort ralentissement de la croissance des tumeurs B16- OVA-HER2. Cet effet anti-tumoral corrèle avec l'enrichissement des lymphocytes T CD8+ spécifiques observé à la tumeur. Afin d'étendre l'application des protéines αGC/sCD1d et d'améliorer leur efficacité, nous avons développé des fusions CD1d alternatives. Premièrement, une protéine αGC/sCD1d dimérique, qui permet d'augmenter l'avidité de la molécule CD1d pour les cellules iNKT. Dans un deuxième temps, nous avons fusionné la protéine αGC/sCD1d avec un scFv dirigé contre le récepteur 3 du facteur de croissance pour l'endothélium vasculaire (VEGFR-3), afin de cibler l'environnement de la tumeur. Dans l'ensemble, ces résultats démontrent que la thérapie médiée par la protéine recombinante αGC/sCD1d-scFv est une approche prometteuse pour rediriger l'immunité innée et adaptive vers le site tumoral. - Invariant Natural Killer T cells (iNKT) are potent activators of Natural Killer (NK), dendritic cells (DC) and T lymphocytes, and their anti-tumor activities have been well demonstrated. However, a single injection of the high affinity CD1d ligand alpha-galactosylceramide (αGC) leads to a strong but short-lived iNKT cell activation followed by a phase of long-term anergy, limiting the therapeutic use of this ligand. As a promising alternative, we have demonstrated that when αGC is loaded on recombinant soluble CD1d molecules (αGC/sCD1d), repeated injections in mice led to the sustained iNKT cell activation associated with continued cytokine secretion. Importantly, the retained reactivity of iNKT cell led to prolonged antitumor activity when the αGC/sCD1d was fused to an anti-tumor scFv fragments. Optimal inhibition of tumor growth was obtained only when mice were treated with the tumor-targeted αGC/CD1d-scFv fusion, whereas the irrelevant αGC/CD1d-scFv fusion was less efficient. When tested in a human system, the recombinant αGC/sCD1d-anti-HER2 and -anti-CEA fusion proteins were able to expand iNKT cells from PBMCs of healthy donors. Furthermore, the αGC/sCD1d-scFv fusion had the capacity to directly activate human iNKT cells clones without the presence of antigen-presenting cells (APCs), in contrast to the free αGC ligand. Most importantly, tumor cell killing by human iNKT cells was obtained only when co- incubated with the tumor targeted sCD1d-antitumor scFv, and their direct tumor cytotoxicity was superior to the bystander killing obtained with αGC-loaded APCs stimulation. To further enhance the anti-tumor effects, we exploited the ability of iNKT cells to transactivate the adaptive immunity, by combining the NKT/CD1d immunotherapy with a peptide cancer vaccine. Interestingly, synergistic effects were obtained when the αGC/sCD1d- anti-HER2 fusion treatment was combined with CpG ODN as adjuvant for the OVA peptide vaccine, as seen by higher numbers of activated antigen-specific CD8 T cells and NK cells, as compared to each regimen alone. The increased innate and adaptive immune responses upon combined tumor targeted sCD1d-scFv treatment and OVA/CpG vaccine were associated with a strong delay in B16-OVA-HER2 melanoma tumor growth, which correlated with an enrichment of antigen-specific CD8 cells at the tumor site. In order to extend the application of the CD1d fusion, we designed alternative CD1d fusion proteins. First, a dimeric αGC/sCD1d-Fc fusion, which permits to augment the avidity of the CD1d for iNKT cells and second, an αGC/sCD1d fused to an anti vascular endothelial growth factor receptor-3 (VEGFR-3) scFv, in order to target tumor stroma environment. Altogether, these results demonstrate that the iNKT-mediated immunotherapy via recombinant αGC/sCD1d-scFv fusion is a promising approach to redirect the innate and adaptive antitumor immune response to the tumor site.

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NK T cells produce cytokines when their semi-invariant TCR engages glycolipids associated with CD1d. The physiological consequences of NKT cell activation remain controversial, although they have been implicated in control of autoimmunity, parasites and tumors. We show here that specific activation of NKT cells in liver and spleen leads to a rapid induction of extensive NK cell proliferation and cytotoxicity. This NK cell activation is dependent, at least in part, on IFN-gamma production by NKT cells and IL-12 production by antigen-presenting cells. Remarkably, activation of NK cells by NKT cells is highly selective, since bystander T and B lymphocytes show transient expression of activation markers but almost no proliferation. Collectively our data suggest that CD1d-dependent NKT cells regulate innate immunity by sampling blood-borne glycolipid antigens and rapidly activating NK cells.