917 resultados para Allograft-rejection
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In extreme situations, such as hyperacute rejection of heart transplant or major heart trauma, heart preservation may not be possible. Our experimental team works on a project of peripheral extracorporeal membrane oxygenation (ECMO) support in acardia as a bridge to heart transplantation or artificial heart implantation. An ECMO support was established in five calves (58.6 ± 6.9 kg) by the transjugular insertion to the caval axis of a self-expanded cannula, with carotid artery return. After baseline measurements, ventricular fibrillation was induced, great arteries were clamped, heart was excised, and right and left atria remnants, containing pulmonary veins, were sutured together leaving an atrial septal defect over the caval axis cannula. Measurements of pump flow and arterial pressure were taken with the pulmonary artery clamped and anastomosed with the caval axis for a total of 6 hours. Pulmonary artery anastomosis to the caval axis provided an acceptable 6 hour hemodynamic stability, permitting a peripheral access ECMO support in extreme scenarios indicating a heart explantation.
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Abstract-Due to the growing use of biometric technologies inour modern society, spoofing attacks are becoming a seriousconcern. Many solutions have been proposed to detect the use offake "fingerprints" on an acquisition device. In this paper, wepropose to take advantage of intrinsic features of friction ridgeskin: pores. The aim of this study is to investigate the potential ofusing pores to detect spoofing attacks.Results show that the use of pores is a promising approach. Fourmajor observations were made: First, results confirmed that thereproduction of pores on fake "fingerprints" is possible. Second,the distribution of the total number of pores between fake andgenuine fingerprints cannot be discriminated. Third, thedifference in pore quantities between a query image and areference image (genuine or fake) can be used as a discriminatingfactor in a linear discriminant analysis. In our sample, theobserved error rates were as follows: 45.5% of false positive (thefake passed the test) and 3.8% of false negative (a genuine printhas been rejected). Finally, the performance is improved byusing the difference of pore quantity obtained between adistorted query fingerprint and a non-distorted referencefingerprint. By using this approach, the error rates improved to21.2% of false acceptation rate and 8.3% of false rejection rate.
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Annual influenza vaccination is recommended in solid organ transplant (SOT) recipients. However, concerns have been raised about the impact of vaccination on antigraft alloimmunity. We evaluated the humoral alloimmune responses to influenza vaccination in a cohort of SOT recipients between October 2008 and December 2011. Anti-HLA antibodies were measured before and 4-8 weeks after influenza vaccination using a solid-phase assay. Overall, 169 SOT recipients were included (kidney = 136, lung = 26, liver = 3, and combined = 4). Five (2.9%) of 169 patients developed de novo anti-HLA antibodies after vaccination, including one patient who developed donor-specific antibodies (DSA) 8 months after vaccination. In patients with pre-existing anti-HLA antibodies, median MFI was not significantly different before and after vaccination (P = 0.73 for class I and P = 0.20 for class II anti-HLA antibodies) and no development of de novo DSA was observed. Five episodes of rejection (2.9%) were observed within 12 months after vaccination, and only one patient had de novo anti-HLA antibodies. The incidence of development of anti-HLA antibodies after influenza vaccination in our cohort of SOT recipients was very low. Our findings indicate that influenza vaccination is safe and does not trigger humoral alloimmune responses in SOT recipients.
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Lymphomatoid granulomatosis is a rare angiocentric and angiodestructive pulmonary angiitis considered as a variant of the lymphoproliferative disorder group. Patients with organ transplantation are at an increased risk for post-transplant lymphoproliferative disorders secondary to their immunosuppression. However, lymphomatoid granulomatosis has rarely been described in patients with renal transplantation. It often presents with severe pulmonary signs. We describe a case whose initial presentation was an isolated VIth nerve palsy. We review the radiological and pathological findings and discuss the etiopathogenesis and therapeutic options of this particular lymphoproliferative disorder. With careful and stepwise reduction in her immunosuppression, our patient showed a complete disappearance of her lymphomatoid granulomatosis, and she is clinically well more than 3 years after the diagnosis, with good kidney function.
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El estudio hasta el momento de la relación entre positivismo criminológico e ideario anarquista de entre siglos (XIX-XX), ha evidenciado la trascendencia del estudio de aquellos dos pensamiento en esa etapa histórica. El desarrollo de la Criminología como ciencia, así como del verdadero núcleo teórico y práctico del anarquismo español, se encuentra en aquel momento histórico de cambio de siglo. La construcción del tipo criminal anarquista, la política criminal desarrollada al efecto, así como las críticas, propuesta y posturas acerca de la cuestión criminal por parte de los anarquistas, revelan un auge discursivo y científico de ambas partes que estaban discutiendo sobre temas verdaderamente de fondo: aquellos sobre la naturaleza, el progreso y la forma de sociedad y Estado. Más allá de las disputas con aquellos autores de la Scuola Italiana, los anarquistas españoles, avivaron un interés decisivo en otro tipo de teorías como el darwinismo o el neomalthusianismo. Más allá del vehemente rechazo a la cárcel y al sistema estatal y capitalista en su conjunto, el desarrollo y utilización en propio sentido de la Ciencia, se fundamentó como herramienta política básica para el pensamiento anarquista. Por su parte, esa misma Ciencia positiva, era el comodín “objetivo” que se usaba de herramienta para una criminalización y persecución política de numerosas disidencias. Desentrañar, por un lado, cómo se articuló cada uno de esos discursos y qué implicaciones y relaciones tuvo, y por otro, qué herencia pervive de aquellas construcciones en nuestro sistema penal y político, son los puntos centrales de esta Tesis.
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La consecución de tolerancia aloespecífica es de mucha relevancia en trasplante. Las células dendríticas (DC) son las principales responsables de la inducción de la respuesta inmune frente a las moléculas de histocompatibilidad (MHC) del donante, provocando el rechazo del injerto. Sin embargo las DC son también responsables de la inducción de tolerancia. Diversos modelos animales de alotrasplante han mostrado la tolerización del injerto mediante DC diferenciadas in vitro en condiciones tolerogénicas (tDC). En humanos, las fuentes de aloantígenos potencialmente utilizables en terapia son, entre otras, los cuerpos apoptóticos y los exosomas. Éstos expresan antígenos MHC de forma abundante y su composición es relativamente uniforme, lo que supone una ventaja frente a otras fuentes. En este proyecto, se ha evaluado la obtención de exosomas secretados por una línea de linfocitos T y por células dendríticas derivadas de médula ósea. Se ha caracterizado la captura de exosomas derivados de linfocitos T por células dendríticas humanas derivadas de sangre periférica y su presentación a linfocitos T autólogos. Por otra parte, se ha comenzado a desarrollar los experimentos para estudiar la inducción de tolerancia en un modelo de trasplante renal en rata. Se han generado células dendríticas tolerógenicas derivadas de médula ósea (tolDC), en presencia de dexametasona. Las tolDC expresan menos moléculas de histocompatibilidad y de coestimulación e inducen una menor proliferación en reacciones mixtas leucocitaras, comparadas con las células dendríticas maduras. Por último, se han caracterizado los exosomas de plasma humano con el fin de estudiar su posible uso como aloantígenos. El análisis proteómico revela la presencia de proteínas relacionadas con el sistema inmune, la coagulación, la señalización celular y moléculas implicadas en el transporte y metabolismo de nutrientes. El estudio de la captura por diferentes líneas celulares sugiere que deben existir mecanismos específicos para su internalización.
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AIMS/HYPOTHESIS: betaTC-tet (H2(k)) is a conditional insulinoma cell line derived from transgenic mice expressing a tetracycline-regulated oncogene. Transgenic expression of several proteins implicated in the apoptotic pathways increase the resistance of betaTC-tet cells in vitro. We tested in vivo the sensitivity of the cells to rejection and the protective effect of genetic alterations in NOD mice. METHODS: betaTC-tet cells and genetically engineered lines expressing Bcl-2 (CDM3D), a dominant negative mutant of MyD88 or SOCS-1 were transplanted in diabetic female NOD mice or in male NOD mice with diabetes induced by high-dose streptozotocin. Survival of functional cell grafts in NOD-scid mice was also analyzed after transfer of splenocytes from diabetic NOD mice. Autoreactive T-cell hybridomas and splenocytes from diabetic NOD mice were stimulated by betaTC-tet cells. RESULTS: betaTC-tet cells and genetically engineered cell lines were all similarly rejected in diabetic NOD mice and in NOD-scid mice after splenocyte transfer. In 3- to 6-week-old male NOD mice treated with high-dose streptozotocin, the cells temporarily survived, in contrast with C57BL/6 mice treated with high-dose streptozotocin (indefinite survival) and untreated 3- to 6-week-old male NOD mice (rejection). The protective effect of high-dose streptozotocin was lost in older male NOD mice. betaTC-tet cells did not stimulate autoreactive T-cell hybridomas, but induced IL-2 secretion by splenocytes from diabetic NOD mice. CONCLUSION/INTERPRETATION: The autoimmune process seems to play an important role in the destruction of betaTC-tet cells in NOD mice. Genetic manipulations intended at increasing the resistance of beta cells were inefficient. Similar approaches should be tested in vivo as well as in vitro. High dose streptozotocin influences immune rejection and should be used with caution.
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Recent studies have shown that CD4+ CD25+ T cells belong to two functionally different T lymphocytes, i.e. regulatory T cells (Treg) or activated T cells (Tact), which can be distinguished based on the expression of CD45RO and IL-7R: Treg (FoxP3+) are CD45RO+ IL-7R- , whereas Tact (FoxP3- ) are CD45RO+ IL- 7R+. In order to determine if a CD4+ CD25+ CD45RO+ IL-7R+ activated T cell population might be identified in kidney transplant recipients, we studied 27 healthy subjects (HS) and 23 kidney recipients, of whom 17 had stable graft function under standard immunosuppression (IS), 5 had biopsy-proven chronic humoral rejection (CHR), and one was a stable "tolerant" patient who had discontinued IS for more than 2 years. Phenotypical analysis by flow cytometry and functional assays by MLR were performed. Overall, the Tact population was found to be significantly increased in 87% of the transplant recipients (mean: 18.8±10.1% of CD4+ CD25+ T cells) compared to HS (mean: 4.5±2.0%; P<0.0001). In the 5 patients with CHR, this Tact population was highly expanded (31.3±9.3%; P<0.0001), whereas it was comparable to HS in the "tolerant" recipient (4.7%). Intermediate levels (16.0±6.9%; P<0.0001) were found in the 17 stable recipients. In CHR, the proliferative capacity of the Tact population was found to be 5-fold higher when stimulated by irradiated donor PBMC as compared to a stimulation by irradiated 3rd party PBMC. After kidney transplantation, an expanded circulating CD4+ CD25+ T cell population characterized by the expression of CD45RO and IL-7R was found in most recipients, particularly in those with CHR. In a patient with long-term operational tolerance, this Tact population was similar to HS. Measuring circulating Tact may become a useful monitoring tool after transplantation.
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Previous studies in our laboratory have shown that DBA/2 mice injected i.p. with syngeneic P815 tumor cells transfected with the HLA-CW3 gene (P815-CW3) showed a dramatic expansion of activated CD8+CD62L- T cells expressing exclusively the Vbeta10 segment. We have used this model to study the regulatory mechanisms involved in the development of the CW3-specific CD8+ response, with respect to different routes of immunization. Whereas both intradermal (i.d.) and i.p. immunization of DBA/2 mice with P815-CW3 cells led to a strong expansion of CD8+CD62L-Vbeta10+ cells, only the i.d. route allowed this expansion after immunization with P815 cells transfected with a minigene coding for the antigenic epitope CW3 170-179 (P815 miniCW3). Furthermore, depletion of CD4+ T cells in vivo completely abolished the specific response of CD8+CD62L-Vbeta10+ cells and prevented the rejection of P815-CW3 tumor cells injected i.p., whereas it did not affect CD8S+CD62L-Vbeta10+ cell expansion after i.d. immunization with either P815-CW3 or P815 miniCW3. Finally, the CW3-specific CD8+ memory response was identical whether or not CD4+ T cells were depleted during the primary response. Collectively, these results suggest that the CD8+ T cell response to P815-CW3 tumor cells injected i.p. is strictly dependent upon recognition of a helper epitope by CD4+ T cells, whereas no such requirement is observed for i.d. injection.
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To achieve the goal of sustained donor-specifi c transplantation (Tx) tolerance, research efforts are now focusing on therapies based on specifi c cell subsets with regulatory properties. We and others have previously highlighted the therapeutic potential of naturally occurring CD4+CD25+Foxp3+ regulatory T cells (nTreg) in promoting long-term graft acceptance. Using more stringent experimental Tx models, we were however confronted to limitations. Indeed, while the transfer of antigenspecifi c nTreg promoted long-term MHC-mismatched skin allograft acceptance in lymphopenic mice in the absence of any immunosuppressive drug, allograft survival was only slightly prolonged when nTreg were transferred alone into non-lymphopenic mice. This suggested that in more stringent conditions, adjuvant therapies may be needed to effectively control alloreactive T cells (Teff). Whether and how the expansion of the Treg pool could be best combined with current immunosuppressive regimens in clinical settings remains to be defi ned. In this study, we have used in vitro assays and an in vivo skin Tx model to investigate the effects of various immunosuppressive drugs on the survival, proliferation and effector function of Teff and nTreg in response to alloantigens. Teff proliferation was inhibited in a dose-dependent manner by rapamycin and cyclosporine A, while anti-CD154 mAb only marginally affected Teff survival, proliferation and effector fucntion in vitro. Rapamycin promoted apoptosis of Teff as compared to nTreg that were more resistant in the presence of IL-2. In vivo, the transfer and/or expansion of Treg could be advantageously combined with rapamycin and anti-CD154 mAb treatment to signifi cantly prolong MHC-mismatched skin allografts survival in non-lymphopenic recipients. Taken together our data indicate that immunosuppressive drugs differentially target T-cell subsets and that some regimens could promote Treg expansion while controlling the Teff pool in response to alloantigens.
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The factors affecting the sexual behaviour of Panstrongylus megistus were studied under laboratory conditions. A general description of mating behaviour is presented for this species. The effect of the time elapsed after the first imaginal feeding on the mating frequency, the motivation of males to mate and the rejection behaviour by females, were analyzed. We also determined the number of copulas accepted by females of this species. Finally, the possible existence of a sexual chemical signal promoting male aggregation around mating couples was evaluated. Results showed that mating frequency increased with the time elapsed since the first adult meal. Despite the number of male copulatory attempts did not change as a function of time, the rejection behaviour of females became gradually less frequent. Females rejected mating by means of body flattening on the substrate, abdominal movements, evasion or stridulation. After a single copula, females did not usually accept to mate again. Neither male nor female aggregation around mating couples was observed, suggesting the absence of a sexual assembling pheromone in P. megistus.
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OBJECTIVE: Eye drops of aganirsen, an antisense oligonucleotide preventing insulin receptor substrate-1 expression, inhibited corneal neovascularization in a previous dose-finding phase II study. We aimed to confirm these results in a phase III study and investigated a potential clinical benefit on visual acuity (VA), quality of life (QoL), and need for transplantation. DESIGN: Multicenter, double-masked, randomized, placebo-controlled phase III study. PARTICIPANTS: Analysis of 69 patients with keratitis-related progressive corneal neovascularization randomized to aganirsen (34 patients) or placebo (35 patients). Patients applied aganirsen eye drops (86 μg/day/eye) or placebo twice daily for 90 days and were followed up to day 180. MAIN OUTCOME MEASURES: The primary end point was VA. Secondary end points included area of pathologic corneal neovascularization, need for transplantation, risk of graft rejection, and QoL. RESULTS: Although no significant differences in VA scores between groups were observed, aganirsen significantly reduced the relative corneal neovascularization area after 90 days by 26.20% (P = 0.014). This improvement persisted after 180 days (26.67%, P = 0.012). Aganirsen tended to lower the transplantation need in the intent-to-treat (ITT) population at day 180 (P = 0.087). In patients with viral keratitis and central neovascularization, a significant reduction in transplantation need was achieved (P = 0.048). No significant differences between groups were observed in the risk of graft rejection. However, aganirsen tended to decrease this risk in patients with traumatic/viral keratitis (P = 0.162) at day 90. The QoL analyses revealed a significant improvement with aganirsen in composite and near activity subscores (P = 0.039 and 0.026, respectively) at day 90 in the per protocol population. Ocular and treatment-related treatment-emergent adverse events (TEAEs) were reported in a lower percentage with aganirsen compared with placebo. Only 3 serious TEAEs (2 with aganirsen and 1 with placebo) were considered treatment-related. CONCLUSIONS: This first phase III study on a topical inhibitor of corneal angiogenesis showed that aganirsen eye drops significantly inhibited corneal neovascularization in patients with keratitis. The need for transplantation was significantly reduced in patients with viral keratitis and central neovascularization. Topical application of aganirsen was safe and well tolerated.
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Antipsychotic medication represents the treatment of choice in psychosis according to clinical guidelines. Nevertheless, studies show that half to almost three-quarter of all patients discontinue medication with antipsychotics after some time, a fact which is traditionally ascribed to side-effects, mistrust against the clinician and poor illness insight. The present study investigated whether positive attitudes toward psychotic symptoms (ie, gain from illness) represent a further factor for medication noncompliance. An anonymous online survey was set up in order to prevent conservative response biases that likely emerge in a clinical setting. Following an iterative selection process, data from a total of 113 patients with a likely diagnosis of schizophrenia and a history of antipsychotic treatment were retained for the final analyses (80%). While side-effect profile and mistrust emerged as the most frequent reasons for drug discontinuation, 28% of the sample reported gain from illness (eg, missing voices, feeling of power) as a motive for noncompliance. At least every fourth patient reported the following reasons: stigma (31%), mistrust against the physician/therapist (31%), and rejection of medication in general (28%). Approximately every fifth patient had discontinued antipsychotic treatment because of forgetfulness. On average, patients provided 4 different explanations for noncompliance. Ambivalence toward symptoms and treatment should thoroughly be considered when planning treatment in psychosis. While antipsychotic medication represents the evidence-based cornerstone of the current treatment in schizophrenia, further research is needed on nonpharmacological interventions for noncompliant patients who are willing to undergo intervention but refuse pharmacotherapy.
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PURPOSE: Ipilimumab is a monoclonal antibody that blocks the immune-inhibitory interaction between CTL antigen 4 (CTLA-4) and its ligands on T cells. Clinical trials in cancer patients with ipilimumab have shown promising antitumor activity, particularly in patients with advanced melanoma. Often, tumor regressions in these patients are correlated with immune-related side effects such as dermatitis, enterocolitis, and hypophysitis. Although these reactions are believed to be immune-mediated, the antigenic targets for the cellular or humoral immune response are not known. EXPERIMENTAL DESIGN: We enrolled patients with advanced melanoma in a phase II study with ipilimumab. One of these patients experienced a complete remission of his tumor. The specificity and functional properties of CD8-positive T cells in his peripheral blood, in regressing tumor tissue, and at the site of an immune-mediated skin rash were investigated. RESULTS: Regressing tumor tissue was infiltrated with CD8-positive T cells, a high proportion of which were specific for Melan-A. The skin rash was similarly infiltrated with Melan-A-specific CD8-positive T cells, and a dramatic (>30-fold) increase in Melan-A-specific CD8-positive T cells was apparent in peripheral blood. These cells had an effector phenotype and lysed Melan-A-expressing tumor cells. CONCLUSIONS: Our results show that Melan-A may be a major target for both the autoimmune and antitumor reactions in patients treated with anti-CTLA-4, and describe for the first time the antigen specificity of CD8-positive T cells that mediate tumor rejection in a patient undergoing treatment with an anti-CTLA-4 antibody. These findings may allow a better integration of ipilimumab into other forms of immunotherapy.
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Trypanosoma cruzi acute infections often go unperceived, but one third of chronically infected individuals die of Chagas disease, showing diverse manifestations affecting the heart, intestines, and nervous systems. A common denominator of pathology in Chagas disease is the minimal rejection unit, whereby parasite-free target host cells are destroyed by immune system mononuclear effectors cells infiltrates. Another key feature stemming from T. cruzi infection is the integration of kDNA minicircles into the vertebrate host genome; horizontal transfer of the parasite DNA can undergo vertical transmission to the progeny of mammals and birds. kDNA integration-induced mutations can enter multiple loci in diverse chromosomes, generating new genes, pseudo genes and knock-outs, and resulting in genomic shuffling and remodeling over time. As a result of the juxtaposition of kDNA insertions with host open reading frames, novel chimeric products may be generated. Germ line transmission of kDNA-mutations determined the appearance of lesions in birds that are indistinguishable from those seen in Chagas disease patients. The production of tissue lesions showing typical minimal rejection units in birds' refractory to T. cruzi infection is consistent with the hypothesis that autoimmunity, likely triggered by integration-induced phenotypic alterations, plays a major role in the pathogenesis of Chagas disease.