Multimodal Treatment Eliminates Cancer Stem Cells and Leads to Long-Term Survival in Primary Human Pancreatic Cancer Tissue Xenografts.

Copyright: 2013 Hermann et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.PURPOSE: In spite of intense research efforts, pancreatic ductal adenocarcinoma remains one of the most deadly malignancies in the world. We and others have previously identified a subpopulation of pancreatic cancer stem cells within the tumor as a critical therapeutic target and additionally shown that the tumor stroma represents not only a restrictive barrier for successful drug delivery, but also serves as a paracrine niche for cancer stem cells. Therefore, we embarked on a large-scale investigation on the effects of combining chemotherapy, hedgehog pathway inhibition, and mTOR inhibition in a preclinical mouse model of pancreatic cancer. EXPERIMENTAL DESIGN: Prospective and randomized testing in a set of almost 200 subcutaneous and orthotopic implanted whole-tissue primary human tumor xenografts. RESULTS: The combined targeting of highly chemoresistant cancer stem cells as well as their more differentiated progenies, together with abrogation of the tumor microenvironment by targeting the stroma and enhancing tissue penetration of the chemotherapeutic agent translated into significantly prolonged survival in preclinical models of human pancreatic cancer. Most pronounced therapeutic effects were observed in gemcitabine-resistant patient-derived tumors. Intriguingly, the proposed triple therapy approach could be further enhanced by using a PEGylated formulation of gemcitabine, which significantly increased its bioavailability and tissue penetration, resulting in a further improved overall outcome. CONCLUSIONS: This multimodal therapeutic strategy should be further explored in the clinical setting as its success may eventually improve the poor prognosis of patients with pancreatic ductal adenocarcinoma

Peptide exchange on MHC-I by TAPBPR is driven by a negative allostery release cycle.

Chaperones TAPBPR and tapasin associate with class I major histocompatibility complexes (MHC-I) to promote optimization (editing) of peptide cargo. Here, we use solution NMR to investigate the mechanism of peptide exchange. We identify TAPBPR-induced conformational changes on conserved MHC-I molecular surfaces, consistent with our independently determined X-ray structure of the complex. Dynamics present in the empty MHC-I are stabilized by TAPBPR and become progressively dampened with increasing peptide occupancy. Incoming peptides are recognized according to the global stability of the final pMHC-I product and anneal in a native-like conformation to be edited by TAPBPR. Our results demonstrate an inverse relationship between MHC-I peptide occupancy and TAPBPR binding affinity, wherein the lifetime and structural features of transiently bound peptides control the regulation of a conformational switch located near the TAPBPR binding site, which triggers TAPBPR release. These results suggest a similar mechanism for the function of tapasin in the peptide-loading complex

Does Preexisting Antiplatelet Treatment Influence Postthrombolysis Intracranial Hemorrhage in Community‐treated Ischemic Stroke Patients? An Observational Study

Objectives Intracranial hemorrhage ( ICH ) after acute stroke thrombolysis is associated with poor outcomes. Previous investigations of the relationship between preexisting antiplatelet use and the safety of intravenous ( IV ) thrombolysis have been limited by low event rates. The objective of this study was to determine whether preexisting antiplatelet therapy increased the risk of ICH following acute stroke thrombolysis. The primary hypothesis was that antiplatelet use would not be associated with radiographic evidence of ICH after controlling for relevant confounders. Methods Consecutive cases of thrombolysis patients treated in the emergency department (ED) were identified using multiple methods. Retrospective data were collected from four hospitals from 1996 to 2004 and 24 other hospitals from 2007 to 2010 as part of a cluster‐randomized trial. The same chart abstraction tool was used during both time periods, and data were subjected to numerous quality control checks. Hemorrhages were classified using a prespecified methodology: ICH was defined as presence of hemorrhage in radiographic interpretations of follow‐up imaging (primary outcome). Symptomatic ICH ( sICH ) was defined as radiographic ICH with associated clinical worsening. A multivariable logistic regression model was constructed to adjust for clinical factors previously identified to be related to postthrombolysis ICH. Sensitivity analyses were conducted where the unadjusted and adjusted results from this study were combined with those of previously published external studies on this topic via meta‐analytic techniques. Results There were 830 patients included, with 47% having documented preexisting antiplatelet treatment. The mean (± standard deviation [SD]) age was 69 (±15) years, and the cohort was 53% male. The unadjusted proportion of patients with any ICH was 15.1% without antiplatelet use and 19.3% with antiplatelet use (absolute risk difference = 4.2%, 95% confidence interval [CI] = −1.2% to 9.6%); for sICH this was 6.1% without antiplatelet use and 9% with antiplatelet use (absolute risk difference = 3.1%, 95% CI = −1% to 6.7%). After adjusting for confounders, antiplatelet use was not significantly associated with radiographic ICH (odds ratio [OR] = 1.1, 95% CI = 0.8 to 1.7) or sICH (OR = 1.3, 95% CI = 0.7 to 2.2). In patients 81 years and older, there was a higher risk of radiographic ICH (absolute risk difference = 11.9%, 95% CI = 0.1% to 23.6%). The meta‐analyses combined the findings of this investigation with previous similar work and found increased unadjusted risks of radiographic ICH (absolute risk difference = 4.9%, 95% CI = 0.7% to 9%) and sICH (absolute risk difference = 4%, 95% CI = 2.3% to 5.6%). The meta‐analytic adjusted OR of sICH for antiplatelet use was 1.6 (95% CI = 1.1 to 2.4). Conclusions The authors did not find that preexisting antiplatelet use was associated with postthrombolysis ICH or sICH in this cohort of community treated patients. Preexisting tobacco use, younger age, and lower severity were associated with lower odds of sICH . The meta‐analyses demonstrated small, but statistically significant increases in the absolute risk of radiographic ICH and sICH , along with increased odds of sICH in patients with preexisting antiplatelet use. Resumen ¿Influye el Tratamiento Antiagregante Previo en la Hemorragia Intracraneal tras la Trombolisis en los Pacientes con Ictus Isquémicos Tratados en la Comunidad? Un Estudio Observacional Objetivos La hemorragia intracraneal ( HIC ) tras la trombolisis de un ictus agudo se asocia con malos resultados. Los estudios previos de la relación entre el uso de antiagregantes y la seguridad de la trombolisis intravenosa ( IV ) han estado limitados por los porcentajes bajos de sucesos. El objetivo de este estudio fue determinar si el tratamiento antiagregante previo está asociado con la evidencia radiológica de HIC tras el control por los factores de confusión relevantes. Metodología Se identificaron los casos consecutivos de pacientes tratados con trombolisis en el SU de múltiples formas. Se recogieron los datos de forma retrospectiva de cuatro hospitales de 1996 a 2004 y de 24 hospitales distintos de 2007 a 2010 como parte de un ensayo clínico aleatorizado en racimos. Se utilizó la misma tabla resumen de historia clínica durante ambos periodos de tiempo y los datos fueron sometidos a numerosos controles de calidad. Las hemorragias se clasificaron siguiendo una metodología preestablecida: la HIC se definió como la presencia de hemorragia en las interpretaciones radiológicas de las imágenes de seguimiento (resultado primario); y la HIC sintomática ( HIC s) se definió como la HIC radiológica asociada con un empeoramiento clínico. Se construyó un modelo multivariable de regresión logística para ajustar los factores clínicos previamente identificados como relacionados con un la HIC tras la trombolisis. Los análisis de sensibilidad se realizaron mediante técnicas de metanálisis y se combinaron los resultados ajustados y no ajustados de esta investigación con los estudios externos previamente publicados en este tema. Resultados Se incluyeron 830 pacientes, de los cuales el 47% tenía documentado tratamiento antiagregante previo. La media de edad fue de 69 años, y el 53% eran varones. La proporción no ajustada de pacientes con cualquier tipo de HIC fue del 15,1% sin toma de antiagregante y del 19,3% con la toma de antiagregante (diferencia del riesgo absoluto 4,2%, IC 95% = −1,2% a 9,6%); y para las HIC s fue del 6,1% sin toma de antiagregantes y del 9% con la toma de antiagregantes (diferencia absoluta del riesgo 3,1%, IC 95% = −1% a 6,7%). Tras ajustar por los factores de confusión, la toma de antiagregantes no se asoció de forma significativa con la HIC radiológica ( OR 1,1, IC 95% = 0,8 a 1,7]) o HIC s ( OR 1,3, IC 95% = 0,7 a 2,2). En los pacientes de 81 años o más, hubo mayor riesgo de HIC radiológica (diferencia de riesgo absoluta 11,9%, IC 95% = 0,1% a 23,6%). El metanálisis que combinó los hallazgos de esta investigación con los trabajos similares previos encontró un riesgo no ajustado incrementado para la HIC radiológica (diferencia absoluta del riesgo 4,9%, IC 95% = 0,7% a 9%) y de HIC s (diferencia absoluta del riesgo 4%, IC 95% = 2,3% a 5,6%). La odds ratio ajustada del metanálisis de HIC s para los pacientes con tratamiento de antigregantes fue de 1,6 ( IC 95% = 1,1 a 2,4). Conclusiones Los autores no encontraron que la toma previa de antigregantes se asocie con la HIC o la HIC s tras la trombolisis en esta cohorte de pacientes tratados en la comunidad. El consumo previo de tabaco, la edad más joven y la menor gravedad se asociaron con odds ratio menores de HIC s. El metanálisis demostró un incremento bajo, aunque estadísticamente significativo, de riesgo absoluto de HIC radiológica o de HIC s, con una odds ratio aumentada de HIC s en los pacientes con toma previa de antiagregantes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96759/1/acem12077.pd

Neurogenesis Drives Stimulus Decorrelation in a Model of the Olfactory Bulb

The reshaping and decorrelation of similar activity patterns by neuronal networks can enhance their discriminability, storage, and retrieval. How can such networks learn to decorrelate new complex patterns, as they arise in the olfactory system? Using a computational network model for the dominant neural populations of the olfactory bulb we show that fundamental aspects of the adult neurogenesis observed in the olfactory bulb -- the persistent addition of new inhibitory granule cells to the network, their activity-dependent survival, and the reciprocal character of their synapses with the principal mitral cells -- are sufficient to restructure the network and to alter its encoding of odor stimuli adaptively so as to reduce the correlations between the bulbar representations of similar stimuli. The decorrelation is quite robust with respect to various types of perturbations of the reciprocity. The model parsimoniously captures the experimentally observed role of neurogenesis in perceptual learning and the enhanced response of young granule cells to novel stimuli. Moreover, it makes specific predictions for the type of odor enrichment that should be effective in enhancing the ability of animals to discriminate similar odor mixtures

Spatial dysregulation of T follicular helper cells impairs vaccine responses in aging.

The magnitude and quality of the germinal center (GC) response decline with age, resulting in poor vaccine-induced immunity in older individuals. A functional GC requires the co-ordination of multiple cell types across time and space, in particular across its two functionally distinct compartments: the light and dark zones. In aged mice, there is CXCR4-mediated mislocalization of T follicular helper (TFH) cells to the dark zone and a compressed network of follicular dendritic cells (FDCs) in the light zone. Here we show that TFH cell localization is critical for the quality of the antibody response and for the expansion of the FDC network upon immunization. The smaller GC and compressed FDC network in aged mice were corrected by provision of TFH cells that colocalize with FDCs using CXCR5. This demonstrates that the age-dependent defects in the GC response are reversible and shows that TFH cells support stromal cell responses to vaccines

Molecular Blocking of CD23 Supports Its Role in the Pathogenesis of Arthritis

BACKGROUND: CD23 is a differentiation/activation antigen expressed by a variety of hematopoietic and epithelial cells. It can also be detected in soluble forms in biological fluids. Initially known as the low-affinity receptor for immunoglobulin E (Fc epsilonRII), CD23 displays various other physiologic ligands such as CD21, CD11b/c, CD47-vitronectin, and mannose-containing proteins. CD23 mediates numerous immune responses by enhancing IgE-specific antigen presentation, regulating IgE synthesis, influencing cell differentiation and growth of both B- and T-cells. CD23-crosslinking promotes the secretion of pro-inflammatory mediators from human monocytes/macrophages, eosinophils and epithelial cells. Increased CD23 expression is found in patients during allergic reactions and rheumatoid arthritis while its physiopathologic role in these diseases remains to be clarified. METHODOLOGY/PRINCIPAL FINDINGS: We previously generated heptapeptidic countrestructures of human CD23. Based on in vitro studies on healthy and arthritic patients' cells, we showed that CD23-specific peptide addition to human macrophages greatly diminished the transcription of genes encoding inflammatory cytokines. This was also confirmed by significant reduction of mediator levels in cell supernatants. We also show that CD23 peptide decreased IgE-mediated activation of both human and rat CD23(+) macrophages. In vivo studies in rat model of arthritis showed that CD23-blocking peptide ameliorates clinical scores and prevent bone destruction in a dose dependent manner. Ex-vivo analysis of rat macrophages further confirmed the inhibitory effect of peptides on their activation. Taken together our results support the role of CD23 activation and subsequent inflammatory response in arthritis. CONCLUSION: CD23-blocking peptide (p30A) prevents the activation of monocytes/macrophages without cell toxicity. Thus, targeting CD23 by antagonistic peptide decreases inflammatory markers and may have clinical value in the treatment of human arthritis and allergic reactions involving CD23

Developmental consequences of perinatal cannabis exposure: behavioral and neuroendocrine effects in adult rodents

Cannabis is the most commonly used illicit drug among pregnant women. Since the endocannabinoid system plays a crucial role in brain development, maternal exposure to cannabis derivatives might result in long-lasting neurobehavioral abnormalities in the exposed offspring. It is difficult to detect these effects, and their underlying neurobiological mechanisms, in clinical cohorts, because of their intrinsic methodological and interpretative issues. The present paper reviews relevant rodent studies examining the long-term behavioral consequences of exposure to cannabinoid compounds during pregnancy and/or lactation. Maternal exposure to even low doses of cannabinoid compounds results in atypical locomotor activity, cognitive impairments, altered emotional behavior, and enhanced sensitivity to drugs of abuse in the adult rodent offspring. Some of the observed behavioral abnormalities might be related to alterations in stress hormone levels induced by maternal cannabis exposure. There is increasing evidence from animal studies showing that cannabinoid drugs are neuroteratogens which induce enduring neurobehavioral abnormalities in the exposed offspring. Several preclinical findings reviewed in this paper are in line with clinical studies reporting hyperactivity, cognitive impairments and altered emotionality in humans exposed in utero to cannabis. Conversely, genetic, environmental and social factors could also influence the neurobiological effects of early cannabis exposure in humans

Evaluation of an open access software for calculating glucose variability parameters of a continuous glucose monitoring system applied at pediatric intensive care unit.

BACKGROUND: Continuous Glucose Monitoring (CGM) has become an increasingly investigated tool, especially with regards to monitoring of diabetic and critical care patients. The continuous glucose data allows the calculation of several glucose variability parameters, however, without specific application the interpretation of the results is time-consuming, utilizing extreme efforts. Our aim was to create an open access software [Glycemic Variability Analyzer Program (GVAP)], readily available to calculate the most common parameters of the glucose variability and to test its usability. METHODS: The GVAP was developed in MATLAB(R) 2010b environment. The calculated parameters were the following: average area above/below the target range (Avg. AUC-H/L); Percentage Spent Above/Below the Target Range (PATR/PBTR); Continuous Overall Net Glycemic Action (CONGA); Mean of Daily Differences (MODD); Mean Amplitude of Glycemic Excursions (MAGE). For verification purposes we selected 14 CGM curves of pediatric critical care patients. Medtronic(R) Guardian(R) Real-Time with Enlite(R) sensor was used. The reference values were obtained from Medtronic(R)'s own software for Avg. AUC-H/L and PATR/PBTR, from GlyCulator for MODD and CONGA, and using manual calculation for MAGE. RESULTS: The Pearson and Spearman correlation coefficients were above 0.99 for all parameters. The initial execution took 30 minutes, for further analysis with the Windows(R) Standalone Application approximately 1 minute was needed. CONCLUSIONS: The GVAP is a reliable open access program for analyzing different glycemic variability parameters, hence it could be a useful tool for the study of glycemic control among critically ill patients