IFN-gamma-producing CD45RA+CD8+ and IL-10-producing CD45RA-CD4+ T cells generated in response to LACK in naive subjects never exposed to Leishmania.

Leishmania guyanensis (L.g.)-specific CD8+ T cells can be isolated from PBMC of subjects who have never been previously exposed to Leishmania. Cells that produce IFN-gamma in response to live L.g. are generated from naive CD45RA+CD8+ T cells. The generation of L.g.-specific CD8+ T cells requires the presence of whole L.g. or UV-irradiated parasite but not the soluble antigens from L.g. promastigotes. The IFN-gamma-producing T cells recognize a specific antigen, the Leishmania homologue of receptors of activated C kinases (LACK) and this antigen but not live L.g. can produce a strong IL-10 response in CD45RA-CD4+ memory T cells from naive subjects. A single epitope (amino acid 156-173) is found to induce the IL-10 synthesis. While the IFN-gamma-producing cells are present among CD45RA+CD8+ T cells that are CD62L-CDR7- and CLA-, the LACK-reactive IL-10-producing cells are CD4+ T cells that are CD62L+CCR7- and CLA-.

Tissue oxygenation and hemodynamic response to NO synthase inhibition in septic shock.

The objective of the study was to evaluate the tissue oxygenation and hemodynamic effects of NOS inhibition in clinical severe septic shock. Eight patients with septic shock refractory to volume loading and high level of adrenergic support were prospectively enrolled in the study. Increasing doses of NOS inhibitors [N(G)-nitro-L-arginine-methyl ester (L-NAME) or N(G)-monomethyl-L-arginine (L-NMMA)] were administered as i.v. bolus until a peak effect = 10 mmHg on mean blood pressure was obtained or until side effects occurred. If deemed clinically appropriate, a continuous infusion of L-NAME was instituted and adrenergic support weaning attempted. The bolus administration of NOS inhibitors transiently increased mean blood pressure by 10 mm Hg in all patients. Seven out of eight patients received an L-NAME infusion, associated over 24 h with a progressive decline in cardiac index (P < 0.001) and an increase in systemic vascular resistance (P < 0.01). Partial or total adrenergic support weaning was rapidly possible in 6/8 patients. Oxygen transport decreased (P < 0.001), but oxygen consumption remained unchanged in those patients in whom it could be measured by indirect calorimetry (5/8). Blood lactate and the difference between tonometric gastric and arterial PCO2 remained unchanged. There were 4/8 ICU survivors. We conclude that nitric oxide synthase inhibition in severe septic shock was followed with a progressive correction of the vasoplegic hemodynamic disturbances with finally normalization of cardiac output and systemic vascular resistances without any demonstrable deterioration in tissue oxygenation.

Diabetes and immune thrombocytopenic purpura: a new association with good response to anti-CD20 therapy.

Type 1 diabetes (T1D) is rarely a component of primary immune dysregulation disorders. We report two cases in which T1D was associated with thrombocytopenia. The first patient, a 13-year-old boy, presented with immune thrombocytopenia (ITP), thyroiditis, and, 3 wk later, T1D. Because of severe thrombocytopenia resistant to immunoglobulins, high-dose steroids, and cyclosporine treatment, anti-cluster of differentiation (CD20) therapy was introduced, with consequent normalization of thrombocytes and weaning off of steroids. Three and 5 months after anti-CD20 therapy, levothyroxin and insulin therapy, respectively, were stopped. Ten months after stopping insulin treatment, normal C-peptide and hemoglobin A1c (HbA1c) levels and markedly reduced anti-glutamic acid decarboxylase (GAD) antibodies were measured. A second anti-CD20 trial for relapse of ITP was initiated 2 yr after the first trial. Anti-GAD antibody levels decreased again, but HbA1c stayed elevated and glucose monitoring showed elevated postprandial glycemia, demanding insulin therapy. To our knowledge, this is the first case in which insulin treatment could be interrupted for 28 months after anti-CD20 treatment. In patient two, thrombocytopenia followed a diagnosis of T1D 6 yr previously. Treatment with anti-CD20 led to normalization of thrombocytes, but no effect on T1D was observed. Concerning the origin of the boys' conditions, several primary immune dysregulation disorders were considered. Thrombocytopenia associated with T1D is unusual and could represent a new entity. The diabetes manifestation in patient one was probably triggered by corticosteroid treatment; regardless, anti-CD20 therapy appeared to be efficacious early in the course of T1D, but not long after the initial diagnosis of T1D, as shown for patient two.

Stalk and sucrose yield in response to nitrogen fertilization of sugarcane under reduced tillage

The objective of this work was to evaluate the agroindustrial production of sugarcane (millable stalks and sucrose yield) after successive nitrogen fertilizations of plant cane and ratoons in a reduced tillage system. The experiment was carried out at Jaboticabal, SP, Brazil, on a Rhodic Eutrustox soil, during four consecutive crop cycles (March 2005 to July 2009). Plant cane treatments consisted of N-urea levels (control, 40, 80, and 120 kg ha-1 N + 120 kg ha-1 P2O5 and K2O in furrow application). In the first and second ratoons, the plant cane plots were subdivided in N-ammonium nitrate treatments (control, 50, 100, and 150 kg ha-1 N + 150 kg ha-1 K2O as top dressing over rows). In the third ratoon, N fertilization was leveled to 100 kg ha-1 in all plots, including controls, to detect residual effects of previous fertilizations on the last crop's cycle. Sugarcane ratoon was mechanically harvested. A weighing truck was used to evaluate stalk yield (TCH), and samples were collected in the field for analysis of sugar content (TSH). Increasing N doses and meteorological conditions promote significant responses in TCH and TSH in cane plant and ratoons, in the average and accumulated yield of the consecutive crop cycles.

Dynamics of multiple lin gene expression in Sphingomonas paucimobilis B90A in response to different hexachlorocyclohexane isomers.

Sphingomonas paucimobilis B90A is able to degrade the alpha-, beta-, gamma-, and delta-isomers of hexachlorocyclohexane (HCH). It contains the genes linA, linB, linC, linD, linE, and linR, which have been implicated in HCH degradation. In this study, dynamic expression of the lin genes was measured in chemostat-grown S. paucimobilis B90A by RNA dot blot hybridization and real-time reverse transcriptase PCR upon exposure to a pulse of different HCH isomers. Irrespective of the addition of HCH, linA, linB, and linC were all expressed constitutively. In contrast, linD and linE were induced with alpha-HCH (2 mg/liter) and gamma-HCH (7 mg/liter). A sharp increase in mRNA levels for linD and linE was observed from 10 to 45 min after the addition of alpha- or gamma-HCH. Induction of linD and linE was not detectable upon the addition of 0.7 mg of gamma-HCH per liter, although the compound was degraded by the cells. The addition of beta-HCH (5 mg/liter) or delta-HCH (20 mg/liter) did not lead to linE and linD induction, despite the fact that 50% of the compounds were degraded. This suggests that degradation of beta- and delta-HCH proceeds by a different pathway than that of alpha- and gamma-HCH.

From institutional repositories to personal collections of learning resources

Institutional digital repositories are a basic piece to provide preservation and reutilization of learning resources. However, their creation and maintenance is usually performed following a top-down approach, causing limitations in the search and reutilization of learning resources. In order to avoid this problem we propose to use web 2.0 functionalities. In this paper we present how tagging can be used to enhance the search and reusability functionalities of institutional learning repositories as well as promoting their usage. The paper also describes the evaluation process that was performed in a pilot experience involving open educational resources.

Early prediction of response to sunitinib after imatinib failure by 18F-fluorodeoxyglucose positron emission tomography in patients with gastrointestinal stromal tumor.

PURPOSE: Positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) was used to evaluate treatment response in patients with gastrointestinal stromal tumors (GIST) after administration of sunitinib, a multitargeted tyrosine kinase inhibitor, after imatinib failure. PATIENTS AND METHODS: Tumor metabolism was assessed with FDG-PET before and after the first 4 weeks of sunitinib therapy in 23 patients who received one to 12 cycles of sunitinib therapy (4 weeks of 50 mg/d, 2 weeks off). Treatment response was expressed as the percent change in maximal standardized uptake values (SUV). The primary end point of time to tumor progression was compared with early PET results on the basis of traditional Response Evaluation Criteria in Solid Tumors (RECIST) criteria. RESULTS: Progression-free survival (PFS) was correlated with early FDG-PET metabolic response (P < .0001). Using -25% and +25% thresholds for SUV variations from baseline, early FDG-PET response was stratified in metabolic partial response, metabolically stable disease, or metabolically progressive disease; median PFS rates were 29, 16, and 4 weeks, respectively. Similarly, when a single FDG-PET positive/negative was considered after 4 weeks of sunitinib, the median PFS was 29 weeks for SUVs less than 8 g/mL versus 4 weeks for SUVs of 8 g/mL or greater (P < .0001). None of the patients with metabolically progressive disease subsequently responded according to RECIST criteria. Multivariate analysis showed shorter PFS in patients who had higher residual SUVs (P < .0001), primary resistance to imatinib (P = .024), or nongastric GIST (P = .002), regardless of the mutational status of the KIT and PDGFRA genes. CONCLUSION: Week 4 FDG-PET is useful for early assessment of treatment response and for the prediction of clinical outcome. Thus, it offers opportunities to individualize and optimize patient therapy.

Auxin-mediated plant architectural changes in response to shade and high temperature.

The remarkable plasticity of their architecture allows plants to adjust growth to the environment and to overcome adverse conditions. Two examples of environmental stresses that drastically affect shoot development are imminent shade and high temperature. Plants in crowded environments and plants in elevated ambient temperature display very similar phenotypic adaptations of elongated hypocotyls in seedlings and elevated and elongated leaves at later developmental stages. The comparable growth responses to shade and high temperature are partly regulated through shared signaling pathways, of which the phytohormone auxin and the phytochrome interacting factors (PIFs) are important components. During both shade- and temperature-induced elongation growth auxin biosynthesis and signaling are upregulated in a PIF-dependent manner. In this review we will discuss recent progress in our understanding of how auxin mediates architectural adaptations to shade and high temperature.

RDM1, a novel RNA recognition motif (RRM)-containing protein involved in the cell response to cisplatin in vertebrates.

A variety of cellular proteins has the ability to recognize DNA lesions induced by the anti-cancer drug cisplatin, with diverse consequences on their repair and on the therapeutic effectiveness of this drug. We report a novel gene involved in the cell response to cisplatin in vertebrates. The RDM1 gene (for RAD52 Motif 1) was identified while searching databases for sequences showing similarities to RAD52, a protein involved in homologous recombination and DNA double-strand break repair. Ablation of RDM1 in the chicken B cell line DT40 led to a more than 3-fold increase in sensitivity to cisplatin. However, RDM1-/- cells were not hypersensitive to DNA damages caused by ionizing radiation, UV irradiation, or the alkylating agent methylmethane sulfonate. The RDM1 protein displays a nucleic acid binding domain of the RNA recognition motif (RRM) type. By using gel-shift assays and electron microscopy, we show that purified, recombinant chicken RDM1 protein interacts with single-stranded DNA as well as double-stranded DNA, on which it assembles filament-like structures. Notably, RDM1 recognizes DNA distortions induced by cisplatin-DNA adducts in vitro. Finally, human RDM1 transcripts are abundant in the testis, suggesting a possible role during spermatogenesis.

Priming for enhanced defence responses by specific inhibition of the Arabidopsis response to coronatine.

The priming agent β-aminobutyric acid (BABA) is known to enhance Arabidopsis resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000 by potentiating salicylic acid (SA) defence signalling, notably PR1 expression. The molecular mechanisms underlying this phenomenon remain unknown. A genome-wide microarray analysis of BABA priming during Pst DC3000 infection revealed direct and primed up-regulation of genes that are responsive to SA, the SA analogue benzothiadiazole and pathogens. In addition, BABA was found to inhibit the Arabidopsis response to the bacterial effector coronatine (COR). COR is known to promote bacterial virulence by inducing the jasmonic acid (JA) response to antagonize SA signalling activation. BABA specifically repressed the JA response induced by COR without affecting other plant JA responses. This repression was largely SA-independent, suggesting that it is not caused by negative cross-talk between SA and JA signalling cascades. Treatment with relatively high concentrations of purified COR counteracted BABA inhibition. Under these conditions, BABA failed to protect Arabidopsis against Pst DC3000. BABA did not induce priming and resistance in plants inoculated with a COR-deficient strain of Pst DC3000 or in the COR-insensitive mutant coi1-16. In addition, BABA blocked the COR-dependent re-opening of stomata during Pst DC3000 infection. Our data suggest that BABA primes for enhanced resistance to Pst DC3000 by interfering with the bacterial suppression of Arabidopsis SA-dependent defences. This study also suggests the existence of a signalling node that distinguishes COR from other JA responses.

The DNA damage response to adeno-associated virus : centrosome overduplication and induction of cell death independently of the spindle checkpoint

Summary: Adeno-associated virus type 2 (AAV2) is a small virus containing single-stranded DNA of approximately 4.7kb in size. Both ends of the viral genome are flanked with inverted terminal repeat sequences (ITRs), which serve as primers for viral replication. Previous work in our laboratory has shown that AAV2 DNA with ultraviolet radiation-generated crosslinks (UV-AAV2) provokes a DNA damage response in the host cell by mimicking a stalled replication fork. Infection of cells with UV-AAV2 leads to a p53-and Chk1-mediated cell cycle arrest at the G2/M border of the cell cycle. However, tumour cells lacking the tumour suppressor protein p53 cannot sustain this arrest and enter a prolonged impaired mitosis, the outcome of which is cell death. The aim of my thesis was to investigate how UV-inactivated AAV2 kilts p53-deficient cancer cells. I found that the UV-AAV2-induced DNA damage signalling induces centriole overduplication in infected cells. The virus is able to uncouple the centriole duplication cycle from the cell cycle, leading to amplified centrosome numbers. Chk1 colocalises with centrosomes in the infected cells and the centrosome overduplication is dependent on the presence of Chk1, as well as on the activities of ATR and Cdk kinases and on the G2 arrest. The UV-AAV2-induced DNA damage signalling inhibits the degradation of cyclin B 1 and securin by the anaphase promoting complex, suggesting that the spindle checkpoint is activated in these mitotic cells. Interference with the spindle checkpoint components Mad2 and BubR1 revealed that the UV-AAV2-provoked mitotic catastrophe occurs independently of spindle checkpoint function, This work shows that, in the p53 deficient cells, UV-AAV2 triggers mitotic catastrophe associated with a dramatic Chk1-dependent overduplication of centrioles and the consequent formation of multiple spindle poles in mitosis. Résumé Le virus associé à l'adénovirus type 2 (AAV2) est un petit virus contenant un simple brin d'ADN d'environ 4.7kb. Des expériences antérieures dans notre laboratoire ont montré que les liens intramoléculaires sur l'ADN de AAV2 provoqués paz l'irradiation aux ultraviolets (UV) ressemblent à une fourche de réplication bloquée, ce qui provoque une réponse aux dommages à l'ADN dans la cellule hôte. L'infection des cellules avec UV-AAV2 résulte en un arrêt du cycle cellulaire à la transition G2/M entraîné par les protéines ATR et Chk1. Cependant, les cellules tumorales auxquelles il manque le suppresseur de tumeur p53 ne peuvent pas tenir cet arrêt et entrent dans une mitose anormale et prolongée qui se terminera par la mort cellulaire. Le but de ma thèse était d'étudier comment l'AAV2 inactivé par l'irradiation UV tue les cellules cancéreuses n'ayant pas p53. Je montre ici que le signal de dommages à l'ADN induit par UV-AAV2 génère une surduplication des centrioles dans les cellules infectées. Le virus est capable de dissocier le cycle de duplication du centriole du cycle cellulaire ce qui crée un nombre amplifié de centrosomes. Chk1 est co-localisé avec le centrosome dans les cellules infectées et la swduplication du centrosome est dépendante de la présence de Chk1, de l'activité des kinases ATR et Cdk et de l'arrêt en G2 de la cellule. Le signal d'ADN endommagé induit par UV-AAV2 réprime la dégradation des protéines cycline B1 et securine par le complexe promoteur de l'anaphase (APC), ce qui suggère que le point de contrôle du fuseau mitotique est activé dans ces cellules en mitose. L'étude d'interférence avec des éléments du point de contrôle du fuseau mitotique, Mad2 et BubR1, a révélé que la catastrophe mitotique provoquée paz UV-AAV2 survient indépendamment du point de contrôle du fuseau mitotique. Ce travail montre que dans les cellules déficientes en p53, UV-AAV2 induit une catastrophe mitotique associée à une surduplication des centrioles dépendant de Chk1 et ayant pour conséquence dramatique la formation de multiples fuseaux mitotiques dans la cellule en mitose.

Dry matter accumulation and mineral nutrition of arracacha in response to nitrogen fertilization

Abstract:The objective of this work was to evaluate the effect of nitrogen fertilization on the growth and yield of arracacha (Arracacia xanthorrhiza), as well as on the plant's nutrient uptake, distribution, and removal. The experiment was carried out in a typical Oxisol, with sandy texture. A randomized complete block design was used, with four replicates. The treatments consisted of five N rates: 0, 50, 100, 200, and 400 kg ha-1. The plots were composed of three 8-m-length rows, spaced at 0.60 m between rows and 0.40 m between plants. The plants were harvested after an 8-month cycle. Nitrogen fertilization significantly increased the proportion of N and S accumulated in stems, and of Ca, Mg, Fe, and Mn in leaves. N supply increased Zn distribution to stems and leaves, whereas high N rates increased Cu allocation to stems more than to the rootstock. High N rates increase plant dry matter (DM) production and nutrient uptake and removal, but do not result in the greatest yield due to the greater development of leaves and stems, and to the lower allocation of DM in storage roots.

Long duration response to levodopa in advanced Parkinson's disease patients treated with subthalamic deep brain stimulation

Résumé La levodopa (LD) est le traitement antiparkinsonien le plus efficace et le plus répandu. Son effet est composé d'une réponse de courte (quelques heures) et de longue durée (jours à semaines). La persistance de cette dernière dans les phases avancées de la maladie de Parkinson est controversée, et sa mesure directe n'a jamais été faite en raison des risques liés à un sevrage complet de LD. La stimulation du noyau sous-thalamique est un nouveau traitement neurochirurgical de la maladie de Parkinson, indiqué dans les formes avancées, qui permet l'arrêt complet du traitement médicamenteux chez certains patients. Nous avons étudié 30 patients qui ont bénéficié d'une telle stimulation, et les avons évalués avant l'intervention sans médicaments, et à 6 mois postopératoires, sans médicaments et sans stimulation. Chez 19 patients, la médication a pu être complètement arrêtée, alors qu'elle a dû être réintroduite chez les 11 patients restants. Au cours des 6 mois qui ont suivi l'intervention, le parkinsonisme s'est aggravé de façon significative dans le groupe sans LD, et non dans le groupe avec LD. Cette différence d'évolution s'explique par la perte de l'effet à long terme de la LD dans le groupe chez qui ce médicament a pu être arrêté. En comparant cette aggravation à la magnitude de l'effet à court terme, la réponse de longue durée correspond environ à 80 pourcent de la réponse de courte durée, et elle lui est inversement corrélée. Parmi les signes cardinaux de la maladie, la réponse de longue durée affecte surtout la bradycinésie et la rigidité, mais pas le tremblement ni la composante axiale. La comparaison du parkinsonisme avec traitement (stimulation et LD si applicable) ne montre aucune différence d'évolution entre les 2 groupes, suggérant que la stimulation compense tant la réponse de courte que de longue durée. Notre travail montre que la réponse de longue durée à la LD demeure significative chez les patients parkinsoniens après plus de 15 ans d'évolution, et suggère que la stimulation du noyau sous-thalamique compense les réponses de courte et de longue durée. Abstract Background: Long duration response to levodopa is supposed to decrease with Parkinson's disease (PD) progression, but direct observation of this response in advanced PD has never been performed. Objective: To study the long duration response to levodopa in advanced PD patients treated with subthalamic deep-brain stimulation. Design and settings: We studied 30 consecutive PD patients who underwent subthalamic deep-brain stimulation. One group had no antiparkinsonian treatment since surgery (no levodopa), while medical treatment had to be reinitiated in the other group (levodopa). Main outcome measures: motor Unified Parkinson's Disease Rating Scale (UPDRS). Results: In comparison with preoperative assessment, evaluation six months postoperatively with stimulation turned off for three hours found a worsening of the motor part of UPDRS in the no-levodopa group. This worsening being absent in the levodopa group, it most probably reflected the loss of the long duration response to levodopa in the no-levodopa group. Stimulation turned on, postoperative motor UPDRS in both groups were similar to preoperative on medication scores, suggesting that subthalamic deep-brain stimulation compensated for both the short and long duration responses to levodopa. Conclusions: Our results suggest that the long duration response to levodopa remains significant even in advanced PD, and that subthalamic deep-brain stimulation compensates for both the short and the long duration resposes to levodopa.

Sugarcane response to nitrogen rates, measured by a canopy reflectance sensor

Abstract:The objective of this work was to evaluate whether a canopy sensor is capable of estimating sugarcane response to N, as well as to propose strategies for handling the data generated by this device during the decision-making process for crop N fertilization. Four N rate-response experiments were carried out, with N rates varying from 0 to 240 kg ha-1. Two evaluations with the canopy sensor were performed when the plants reached average stalk height of 0.3 and 0.5 m. Only two experiments showed stalk yield response to N rates. The canopy sensor was able to identify the crop response to different N rates and the relationship of the nutrient with sugarcane yield. The response index values obtained from the canopy sensor readings were useful in assessing sugarcane response to the applied N rate. Canopy reflectance sensors can help to identify areas responsive to N fertilization and, therefore, improve sugarcane fertilizer management.