995 resultados para Dependent Ligand Dissociation


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Cross-sectional study that used the Social Network Index and the genogram to assess the social network of 110 family caregivers of dependent patients attended by a Home Care Service in São Paulo, Brazil. Data were analyzed using the test U of Mann-Whitney, Kruskal-Wallis and Spearman correlation. Results were considered statistically significant when p<0,05. Few caregivers participated in activities outside the home and the average number of people they had a bond was 4,4 relatives and 3,6 friends. Caregivers who reported pain and those who had a partner had higher average number of relatives who to trust. The average number of friends was higher in the group that reported use of medication for depression. Total and per capita incomes correlated with the social network. It was found that family members are the primary caregiver’s social network.





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Integrin receptors are the main mediators of cell adhesion to the extracellular matrix. They bind to their ligands by interacting with short amino acid sequences, such as the RGD sequence. Soluble, small RGD-based peptides have been used to block integrin-binding to ligands, thereby interfering with cell adhesion, migration and survival, while substrate-immobilized RGD sequences have been used to enhance cell binding to artificial surfaces. This approach has several important medical applications, e.g. in suppression of tumor angiogenesis or stimulation of bone formation around implants. However, the relatively weak affinity of short RGD-containing peptides often results in incomplete integrin inhibition or ineffective ligation. In this work, we designed and synthesized several new multivalent RGD-containing molecules and tested their ability to inhibit or to promote integrin-dependent cell adhesion when used in solution or immobilized on substrates, respectively. These molecules consist of an oligomeric structure formed by alpha-helical coiled coil peptides fused at their amino-terminal ends with an RGD-containing fragment. When immobilized on a substrate, these peptides specifically promoted integrin alphaVbeta3-dependent cell adhesion, but when used in solution, they blocked alphaVbeta3-dependent cell adhesion to the natural substrates fibronectin and vitronectin. One of the peptides was nearly 10-fold more efficient than fibronectin or vitronectin in promoting cell adhesion, and almost 100-fold more efficient than a linear RGD tripeptide in blocking adhesion. These results indicate that alpha-helical coiled coil peptides carrying an amino-terminal RGD motif can be used as soluble antagonists or surface-immobilized agonists to efficiently inhibit or promote integrin alphaVbeta3-mediated cell adhesion, respectively.

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Aldosterone increases transepithelial Na+ transport in the urinary bladder of Bufo marinus. The response is characterized by 3 distinct phases: 1) a lag period of about 60 min, ii) an initial phase (early response) of about 2 hr during which Na+ transport increases rapidly and transepithelial electrical resistance falls, and iii) a late phase (late response) of about 4 to 6 hr during which Na+ transport still increases significantly but with very little change in resistance. Triiodothyronine (T3, 6 nM) added either 2 or 18 hr before aldosterone selectively antagonizes the late response. T3 per se (up to 6 nM) has no effect on base-line Na+ transport. The antagonist activity of T3 is only apparent after a latent period of about 6 to 8 hr. It is not rapidly reversible after a 4-hr washout of the hormone. The effects appear to be selective for thyromimetic drugs since reverse T3 (rT3) is inactive and isopropyldiiodothyronine (isoT2) is more active than T3. The relative activity of these analogs corresponds to their relative affinity for T3 nuclear binding sites which we have previously described. Our data suggest that T3 might control the expression of aldosterone by regulating gene expression, e.g. by the induction of specific proteins, which in turn will inhibit the late mineralocorticoid response, without interaction with the early response.

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Peroxisome proliferators regulate the transcription of genes by activating ligand-dependent transcription factors, which, due to their structure and function, can be assigned to the superfamily of nuclear hormone receptors. Three such peroxisome proliferator-activated receptors (PPAR alpha, beta, and gamma) have been cloned in Xenopus laevis. Their mRNAs are expressed differentially; xPPAR alpha and beta but not xPPAR gamma are expressed in oocytes and embryos. In the adult, expression of xPPAR alpha and beta appears to be ubiquitous, and xPPAR gamma is mainly observed in adipose tissue and kidney. Immunocytochemical analysis revealed that PPARs are nuclear proteins, and that their cytoplasmic-nuclear translocation is independent of exogenous activators. A target gene of PPARs is the gene encoding acyl-CoA oxidase (ACO), which catalyzes the rate-limiting step in the peroxisomal beta-oxidation of fatty acids. A peroxisome proliferator response element (PPRE), to which PPARs bind, has been identified within the promoter of the ACO gene. Besides the known xenobiotic activators of PPARs, such as hypolipidemic drugs, natural activators have been identified. Polyunsaturated fatty acids at physiological concentrations are efficient activators of PPARs, and 5,8,11,14-eicosatetraynoic acid (ETYA), which is the alkyne homolog of arachidonic acid, is the most potent activator of xPPAR alpha described to date. Taken together, our data suggest that PPARs have an important role in lipid metabolism.

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PURPOSE: To describe the characteristics of reversible focal pleural thickenings (PTs) mimicking real plaques, that firstly suggest asbestos exposure or pleural metastasis; to propose an imaging strategy and propose an explanation for their mechanism of formation. PATIENTS AND METHODS: Retrospective review of data from 19 patients with PTs fitting the description of pleural plaques at chest computed tomography (CT) and presenting modifications (clearance or appearance) of at least one PT at an additional chest examination in prone position. RESULTS: A total of 152 PTs were recorded on the first chest CT examinations with a range of two to 19 pleural opacities per patient. All PTs had a posterior distribution in the lower lobes. On the additional acquisitions, 144 PTs disappeared. Seventeen patients presented complete regression of PTs and two patients presented persistence of eight PTs. CONCLUSION: Additional low dose acquisition in prone position should be performed in all patients presenting with focal PT in a dependent and basal location. This may allow to exclude a pleural plaque in case of asbestos exposure but also a pleural metastasis in oncologic patients. These reversible dependent PTs could be related to physiological focal accumulation of lymphatic fluid in subpleural area.

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In the plant-beneficial soil bacterium and biocontrol model organism Pseudomonas fluorescens CHA0, the GacS/GacA two-component system upregulates the production of biocontrol factors, i.e. antifungal secondary metabolites and extracellular enzymes, under conditions of slow, non-exponential growth. When activated, the GacS/GacA system promotes the transcription of a small regulatory RNA (RsmZ), which sequesters the small RNA-binding protein RsmA, a translational regulator of genes involved in biocontrol. The gene for a second GacA-regulated small RNA (RsmY) was detected in silico in various pseudomonads, and was cloned from strain CHA0. RsmY, like RsmZ, contains several characteristic GGA motifs. The rsmY gene was expressed in strain CHA0 as a 118 nt transcript which was most abundant in stationary phase, as revealed by Northern blot and transcriptional fusion analysis. Transcription of rsmY was enhanced by the addition of the strain's own supernatant extract containing a quorum-sensing signal and was abolished in gacS or gacA mutants. An rsmA mutation led to reduced rsmY expression, via a gacA-independent mechanism. Overexpression of rsmY restored the expression of target genes (hcnA, aprA) to gacS or gacA mutants. Whereas mutants deleted for either the rsmY or the rsmZ structural gene were not significantly altered in the synthesis of extracellular products (hydrogen cyanide, 2,4-diacetylphloroglucinol, exoprotease), an rsmY rsmZ double mutant was strongly impaired in this production and in its biocontrol properties in a cucumber-Pythium ultimum microcosm. Mobility shift assays demonstrated that multiple molecules of RsmA bound specifically to RsmY and RsmZ RNAs. In conclusion, two small, untranslated RNAs, RsmY and RsmZ, are key factors that relieve RsmA-mediated regulation of secondary metabolism and biocontrol traits in the GacS/GacA cascade of strain CHA0.

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BACKGROUND AND AIMS: In various populations, vitamin D deficiency is associated with chronic diseases and mortality. We examined the association between concentration of circulating 25-hydroxyvitamin D [25(OH)D], a marker of vitamin D status, and all-cause as well as cause-specific mortality. METHODS AND RESULTS: The study included 3404 participants of the general adult Swiss population, who were recruited between November 1988 and June 1989 and followed-up until the end of 2008. Circulating 25(OH)D was measured by protein-bound assay. Cox proportional hazards regression was used to examine the association between 25(OH)D concentration and all-cause and cause-specific mortality adjusting for sex, age, season, diet, nationality, blood pressure, and smoking status. Per 10 ng/mL increase in 25(OH)D concentration, all-cause mortality decreased by 20% (HR = 0.83; 95% CI 0.74-0.92). 25(OH)D concentration was inversely associated with cardiovascular mortality in women (HR = 0.68, 95% CI 0.46-1.00 per 10 ng/mL increase), but not in men (HR = 0.97; 95% CI 0.77-1.23). In contrast, 25(OH)D concentration was inversely associated with cancer mortality in men (HR = 0.72, 95% CI 0.57-0.91 per 10 ng/mL increase), but not in women (HR = 1.14, 95% CI 0.93-1.39). Multivariate adjustment only slightly modified the 25(OH)D-mortality association. CONCLUSION: 25(OH)D was similarly inversely related to all-cause mortality in men and women. However, we observed opposite effects in women and men with respect to cardiovascular and cancer mortality.

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An in vitro model, the aggregating brain cell culture of fetal rat telencephalon, has been used to study the maturation-dependent sensitivity of brain cells to two organophosphorus pesticides (OPs), chlorpyrifos and parathion, and to their oxon derivatives. Immature (DIV 5-15) or differentiated (DIV 25-35) brain cells were treated continuously for 10 days. Acetylcholinesterase (AChE) inhibitory potency for the OPs was compared to that of eserine (physostigmine), a reversible AChE inhibitor. Oxon derivatives were more potent AChE inhibitors than the parent compounds, and parathion was more potent than chlorpyrifos. No maturation-dependent differences for AChE inhibition were found for chlorpyrifos and eserine, whereas for parathion and paraoxon there was a tendency to be more effective in immature cultures, while the opposite was true for chlorpyrifos-oxon. Toxic effects, assessed by measuring protein content as an index of general cytotoxicity, and various enzyme activities as cell-type-specific neuronal and glial markers (ChAT and GAD, for cholinergic and GABAergic neurons, respectively, and GS and CNP, for astrocytes and oligodendrocytes, respectively) were only found at more than 70% of AChE inhibition. Immature compared to differentiated cholinergic neurons appeared to be more sensitive to OP treatments. The oxon derivates were found to be more toxic on neurons than the parent compounds, and chlorpyrifos was more toxic than parathion. Eserine was not neurotoxic. These results indicate that inhibition of AChE remains the most sensitive macromolecular target of OP exposure, since toxic effects were found at concentrations in which AChE was inhibited. Furthermore, the compound-specific reactions, the differential pattern of toxicity of OPs compared to eserine, and the higher sensitivity of immature brain cells suggest that the toxic effects and inhibition of AChE are unrelated.

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Treatment of B cell lymphoma patients with MoAbs specific for the common B cell marker (CD20) has shown a good overall response rate, but the number of complete remissions is still very low. The use of MoAbs coupled to radioisotopes can improve the results, but induces undesirable myelodepression. As an alternative, we proposed to combine the specificity of MoAbs with the immunogenicity of T cell epitopes. We have previously shown that an anti-Ig lambda MoAb coupled to an MHC class II-restricted universal T cell epitope peptide P2 derived from tetanus toxin induces efficient lysis of a human B cell lymphoma by a specific CD4+ T cell line. Here we demonstrate that the antigen presentation properties of the MoAb peptide conjugate are maintained using a MoAb directed against a common B cell marker, CD19, which is known to be co-internalized with the B cell immunoglobulin receptor. In addition, we provide evidence that B cell lysis is mediated by the Fas apoptosis pathway, since Fas (CD95), but not tumour necrosis factor receptor (TNFr) or TNF-related receptors, is expressed by the target B cells, and FasL, but not perforin, is expressed by the effector T cells. These results show that B cell lymphomas can be 'foreignized' by MoAb-peptide P2 conjugates directed against the common B cell marker CD19 and eliminated by peptide P2-specific CD4+ T cells, via the ubiquitous Fas receptor. This approach, which bridges the specificity of passive antibody therapy with an active T cell immune response, may be complementary to and more efficient than the present therapy results with unconjugated chimeric anti-CD20 MoAbs.

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Abstract OBJECTIVE To identify the factors associated with involuntary hospital admissions of technology-dependent children, in the municipality of Ribeirão Preto, São Paulo State, Brazil. METHOD A cross-sectional study, with a quantitative approach. After an active search, 124 children who qualified under the inclusion criteria, that is to say, children from birth to age 12, were identified. Data was collected in home visits to mothers or the people responsible for the children, through the application of a questionnaire. Analysis of the data followed the assumptions of the Generalized Linear Models technique. RESULTS 102 technology-dependent children aged between 6 months and 12 years participated in the study, of whom 57% were male. The average number of involuntary hospital admissions in the previous year among the children studied was 0.71 (±1.29). In the final model the following variables were significantly associated with the outcome: age (OR=0.991; CI95%=0.985-0.997), and the number of devices (OR=0.387; CI95%=0.219-0.684), which were characterized as factors of protection and quantity of medications (OR=1.532; CI95%=1.297-1.810), representing a risk factor for involuntary hospital admissions in technology-dependent children. CONCLUSION The results constitute input data for consideration of the process of care for technology-dependent children by supplying an explanatory model for involuntary hospital admissions for this client group.

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Homologous desensitization and internalization of the GLP-1 receptor correlate with phosphorylation of the receptor in a 33-amino acid segment of the cytoplasmic tail. Here, we identify the sites of phosphorylation as being three serine doublets located at positions 441/442, 444/445, and 451/452. The role of phosphorylation on homologous desensitization was assessed after stable expression in fibroblasts of the wild type or of mutant receptors in which phosphorylation sites were changed in various combinations to alanines. We showed that desensitization, as measured by a decrease in the maximal production of cAMP after a first exposure of the cells to GLP-1, was strictly dependent on phosphorylation. Furthermore, the number of phosphorylation sites correlated with the extent of desensitization with no, intermediate, or maximal desensitization observed in the presence of one, two, or three phosphorylation sites, respectively. Internalization of the receptor-ligand complex was assessed by measuring the rate of internalization of bound [125I]GLP-1 or the redistribution of the receptor to an endosomal compartment after agonist binding. Our data demonstrate that internalization was prevented in the absence of receptor phosphorylation and that intermediate rates of endocytosis were obtained with receptors containing one or two phosphorylation sites. Thus, homologous desensitization and internalization require phosphorylation of the receptor at the same three sites. However, the differential quantitative impairment of these two processes in the single and double mutants suggests different molecular mechanisms controlling desensitization and internalization.

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A recombinant baculovirus encoding a single-chain murine major histocompatibility complex class I molecule in which the first three domains of H-2Kd are fused to beta 2-microglobulin (beta 2-m) via a 15-amino acid linker has been isolated and used to infect lepidopteran cells. A soluble, 391-amino acid single-chain H-2Kd (SC-Kd) molecule of 48 kDa was synthesized and glycosylated in insect cells and could be purified in the absence of detergents by affinity chromatography using the anti-H-2Kd monoclonal antibody SF1.1.1.1. We tested the ability of SC-Kd to bind antigenic peptides using a direct binding assay based on photoaffinity labeling. The photoreactive derivative was prepared from the H-2Kd-restricted Plasmodium berghei circumsporozoite protein (P.b. CS) peptide 253-260 (YIPSAEKI), a probe that we had previously shown to be unable to bind to the H-2Kd heavy chain in infected cells in the absence of co-expressed beta 2-microglobulin. SC-Kd expressed in insect cells did not require additional mouse beta 2-m to bind the photoprobe, indicating that the covalently attached beta 2-m could substitute for the free molecule. Similarly, binding of the P.b. CS photoaffinity probe to the purified SC-Kd molecule was unaffected by the addition of exogenous beta 2-m. This is in contrast to H-2KdQ10, a soluble H-2Kd molecule in which beta 2-m is noncovalently bound to the soluble heavy chain, whose ability to bind the photoaffinity probe is greatly enhanced in the presence of an excess of exogenous beta 2-m. The binding of the probe to SC-Kd was allele-specific, since labeling was selectively inhibited only by antigenic peptides known to be presented by the H-2Kd molecule.

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Food allergy in children significantly affects their quality of life. Its impact can be analyzed by quality of life questionnaires. The aim of our study was to validate the French version of disease-specific questionnaires and to evaluate the quality of life in children with IgE-mediated food allergy. Two validated food allergy-specific questionnaires for quality of life, the parent's and children's forms (FAQLQ-PF and FAQLQ-CF), were translated from English to French and submitted to children with food allergy and their parents. Questionnaires were analyzed in terms of emotional impact, food anxiety, and social and food limitations. NCT 01480427. Sixty-two parents of children aged 0-12 yrs answered the FAQLQ-PF, and 32 children aged 8-12 yrs the FAQLQ-CF. Construct validity of both questionnaires was assessed by correlation between the FAQLQs and FAIM (r = 0.85 and 0.84, respectively). Both FAQLQs had good internal consistency (Cronbach's α = 0.748 and 0.67, respectively). Young children (0-3 yrs old) showed better quality of life scores than older children (FAQLQ-PF global score: p = 0.02). Worse scores were also shown among children with previous severe systemic reactions (FAQLQ-PF global score: p = 0.039), the ones with an allergic mother (FAQLQ-PF global score: p = 0.002), or allergic siblings (FAQLQ-PF emotional impact score: p = 0.034), the ones with multiple food allergy (more than 1 food) (FAQLQ-PF anxiety score: p = 0.04) and among the girls (FAQLQ-CF global score: p = 0.031). Older children, the ones with severe systemic reactions, or with mothers or siblings also affected by allergies, as well as girls, and children with multiple food allergies show worse quality of life scores.

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Résumé II y a cinq ans, la découverte d'un nouveau domaine, le PYD domaine, lié aux domaines de la mort, a permis la description de la nouvelle famille des NALP protéines. L'analyse structurelle de cette famille de protéines révéla la présence de deux autres domaines, impliqués dans l'oligomerisation, NACHT, et la détection des ligands, Leucine rich repeats ou LRR. Cette architecture protéique est homologue à celle qui est décrite pour les NODs, les Tol1 récepteurs et tes protéines de résistance chez les plantes. Cette homologie suggère une possible implication des NALPs dans la régulation de l'immunité innée. Premièrement, nous avons décrit les composants minimaux qui permettent à l'inflammasomeNALP3 d'activer la caspase pro-inflammatoire, caspase-1. En comparaison à NALP1, NALP3 ne contient pas de FIIND domaine, ni de CARD domaine en C-terminus et n'interagit pas avec caspase-5. Nous avons découvert une protéine très homologue au C-terminus de NALP1, Cardinal, qui se lie au NACHT domaine de NALP2 et NALP3 par l'intermédiaire de son FIIND domaine. Cardinal possède la capacité d'interagir avec caspase-l, mais seul ASC semble être nécessaire à la maturation de la prointerleukine-1β suite à la stimulation de NALP3. Deuxièmement, notre étude s'est concentrée sur la nature du stimulus capable d'induire la formation et l'activation de l'inflammasome-NALP3. Nous avons démontré que l'ajout de muramyl dipeptide (MDP), produit à partir de la digestion enzymatique de peptidoglycaris bactériens, induit à la fois l'expression de la proIL-1β par la voie NOD2 et sa maturation en IL-1β active par la voie NALP3. Bien que le MDP active l'inflammasome-NALP3, il est incapable d'induire la sécrétion de l'IL-1β mature dans la lignée cellulaire THP1, comparé aux monocytes primaires humains. Cette différence pourrait être liée à l'absence, dans les THP1, de la protéine Filamin, qui est proposée d'interagir avec Cardinal. L'implication de NALP3 dans la maturation de l'IL-lb est confirmée suite à la découverte de mutations sur le gène CIAS1/NALP3/cryopyrin associées à trois maladies auto-inflammatoires : le syndrome de Muckle-Wells (MWS), l'urticaire familial au froid (FCU) et le syndrome CINCA/NOMID. Une élévation constitutive de la maturation et de la sécrétion de la proIL-1β en absence de stimulation MDP est détectée dans les macrophages des patients Muckle-Wells. En conclusion, nos études ont démontré que l'inflammasome-NALP3 doit être finement régulé pour éviter une activité incontrôlée qui représente la base moléculaire des symptômes associés aux syndromes auto-inflammatoires liés à NALP3. Summary Five years ago, the description of the NALP family originated from the discovery of a new death-domain fold family, the PYD domain. NALP contains aprotein-protein interaction domain (PYD), an oligomerization domain (NACHT) and a ligand-sensing domain, leucine rich repeats or LRR. This protein architecture shares similarity with receptors involved in immunity, such as NODS, Toll receptors (TLRs) and related plant resistance proteins, and points to an important role of NALPs in defense mechanisms. We first described the minimal complex involved in the pro-inflammatory Interleukin-1beta (IL-1β) cytokine maturation, called the inflammasome, which contains NALP3. In contrast to NALP1, NALP3, like other members of the NALP family, is devoid of C-terminal FIIND and CARD domains and does not interact with the pro-inflammatory caspase-5. Interestingly, a homolog of the C-terminal portion of NALP1 was found in the human genome and was named Cardinal. We found that NALP2 and NALP3 interact with the CARD-containing proteins Cardinal. Cardinal is able to bind to caspase-1 but is not required for IL-1β maturation through NALP3 activation, as demonstrated for the adaptor ASC. Secondly, our study focused on the stimuli involved in the activation of the NALP3 inflammasome. MDP was shown to induce the expression of proIL1β through NOD2 and then the maturation into active IL-1β by activation of the NALP3 inflammasome. However, in the monocytic THP1 cell line, secretion of IL-1β upon MDP stimulation seems to be independent of the inflammasome activation compared to human primary monocytes. This difference might be linked to a Cardinal-interacting protein, filamin. Until now, the role of Cardinal and filamin is still unknown and remains to be elucidated. Finally, mutations in the NALP3/cryopyrin/CIAS1 gene are associated with three autoinflammatory diseases: Muckle-Wells syndrome, familial cold autoinflammatory syndrome, and CINCA. Constitutive, elevated IL-1β maturation and secretion, even in the absence of MDP stimulation, was observed in macrophages from Muckle-Wells patients and confirmed a key role for the NALP3 inflammasome in innate immunity In conclusion, our studies describes the formation of the NALP3 inflammasome and suggests that this complex has to be tightly regulated to avoid an increased deregulated inflammasome activity that is the molecular basis for the symptoms associated with NALP3-dependent autoinflammatory disorders.

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We establish the validity of subsampling confidence intervals for themean of a dependent series with heavy-tailed marginal distributions.Using point process theory, we study both linear and nonlinear GARCH-liketime series models. We propose a data-dependent method for the optimalblock size selection and investigate its performance by means of asimulation study.