Structural prediction of peptides bound to MHC class I.

An ab initio structure prediction approach adapted to the peptide-major histocompatibility complex (MHC) class I system is presented. Based on structure comparisons of a large set of peptide-MHC class I complexes, a molecular dynamics protocol is proposed using simulated annealing (SA) cycles to sample the conformational space of the peptide in its fixed MHC environment. A set of 14 peptide-human leukocyte antigen (HLA) A0201 and 27 peptide-non-HLA A0201 complexes for which X-ray structures are available is used to test the accuracy of the prediction method. For each complex, 1000 peptide conformers are obtained from the SA sampling. A graph theory clustering algorithm based on heavy atom root-mean-square deviation (RMSD) values is applied to the sampled conformers. The clusters are ranked using cluster size, mean effective or conformational free energies, with solvation free energies computed using Generalized Born MV 2 (GB-MV2) and Poisson-Boltzmann (PB) continuum models. The final conformation is chosen as the center of the best-ranked cluster. With conformational free energies, the overall prediction success is 83% using a 1.00 Angstroms crystal RMSD criterion for main-chain atoms, and 76% using a 1.50 Angstroms RMSD criterion for heavy atoms. The prediction success is even higher for the set of 14 peptide-HLA A0201 complexes: 100% of the peptides have main-chain RMSD values < or =1.00 Angstroms and 93% of the peptides have heavy atom RMSD values < or =1.50 Angstroms. This structure prediction method can be applied to complexes of natural or modified antigenic peptides in their MHC environment with the aim to perform rational structure-based optimizations of tumor vaccines.

Multimodel inference and multimodel averaging in empirical modeling of occupational exposure levels.

Empirical modeling of exposure levels has been popular for identifying exposure determinants in occupational hygiene. Traditional data-driven methods used to choose a model on which to base inferences have typically not accounted for the uncertainty linked to the process of selecting the final model. Several new approaches propose making statistical inferences from a set of plausible models rather than from a single model regarded as 'best'. This paper introduces the multimodel averaging approach described in the monograph by Burnham and Anderson. In their approach, a set of plausible models are defined a priori by taking into account the sample size and previous knowledge of variables influent on exposure levels. The Akaike information criterion is then calculated to evaluate the relative support of the data for each model, expressed as Akaike weight, to be interpreted as the probability of the model being the best approximating model given the model set. The model weights can then be used to rank models, quantify the evidence favoring one over another, perform multimodel prediction, estimate the relative influence of the potential predictors and estimate multimodel-averaged effects of determinants. The whole approach is illustrated with the analysis of a data set of 1500 volatile organic compound exposure levels collected by the Institute for work and health (Lausanne, Switzerland) over 20 years, each concentration having been divided by the relevant Swiss occupational exposure limit and log-transformed before analysis. Multimodel inference represents a promising procedure for modeling exposure levels that incorporates the notion that several models can be supported by the data and permits to evaluate to a certain extent model selection uncertainty, which is seldom mentioned in current practice.

International consensus conference on PFAPA syndrome: Evaluation of a new set of diagnostic criteria

The PFAPA syndrome is characterized by periodic fever, associated with pharyngitis, cervical adenitis and/or aphtous stomatitis and belongs to the auto-inflammatory diseases. Diagnostic criteria are based on clinical features and the exclusion of other periodic fever syndromes. An analysis of a large cohort of patients has shown weaknesses for these criteria and there is a lack of international consensus. An International Conference was held in Morges in November 2008 to propose a new set of classification criteria based on a consensus among experts in the field. We aimed to verify the applicability of the new set of classification criteria. 80 patients diagnosed with PFAPA syndrome from 3 centers (Genoa, Lausanne and Geneva) for pediatric rheumatology were included in the study. A detailed description of the clinical and laboratory features was obtained. The new classification criteria and the actual diagnostic criteria were applied to the patients. Only 43/80 patients (53.8%) fulfilled all criteria of the new classification. 31 patients were excluded because they didn't meet one of the 7 diagnostic criteria, 8 because of 2 criteria, and one because of 3 criteria. When we applied the current criteria to the same patients, 11/80 patients (13%) needed to be excluded. 8/80 patients (10%) were excluded from both sets. Exclusion was related only to some of the criteria. Number of patients for each not fulfilled criterion (new set of criteria/actual criteria): age (1/6), symptoms between episodes (2/2), delayed growth (3/3), main symptoms (21/0), periodicity, length of fever, interval between episodes, and length of disease (19/0). The application of some of the new criteria was not easy, as they were both very restrictive and needed precise information from the patients. Our work has shown that the new set of classification criteria can be applied to patients suspected for PFAPA syndrome, but it seems to be more restrictive than the actual diagnostic criteria. A further work of validation needs to be done for this new set of classification criteria in order to determine if these criteria allow a good discrimination between PFAPA patients and other causes of recurrent fever syndromes.

Intestinal Helminthiasis and Anaemia in Youngsters from Matriz da Luz, District of São Lourenço da Mata, State of Pernambuco, Brazil

A group of youngsters (4-18 years old) in northeast Brazil was studied to establish the prevalence of anaemia and intestinal parasitism, as well as to analyze the correlation between them. Two criteria were used to determine the state of anaemia, the level of haemoglobin and the mean of corpuscular volume. The first was considered a single criterion and the second an associated criteria, used in an attempt to correlate anaemia with iron deficiency. The prevalence of intestinal parasitism was 93%, while the prevalence of anaemia was 43.1% and 16.1% according to the criteria employed (single or associated respectively). Anaemia was significantly associated with both sex and age. No significant statistical difference was observed when the association was made between each parasite and anaemia even with those more related to anaemia.

Octacalcium Phosphate (OCP) Crystals Induce Synovial Inflammation and Cartilage

Introduction: The presence of intra-articular basic calcium phosphate (BCP) crystals, including OCP, carbonated-apatite, hydroxyapatite and tricalcium phosphate crystals, is associated with severe osteoarthritis and destructive arthropathies such as Milwaukee shoulder. Although BCP crystals displayed, in vitro, mitogenic, anabolic and catabolic responses, their intra-articular effect was never assessed.Objective: To determine the effects of OCP crystals in joints in vivo.Methods: OCP crystals (200 ug in 20 ml PBS) were injected into the right knee joint (the contra-lateral knee joint injected with 20 ul of PBS serving as a control) of wild-type mice treated or not by the IL1R antagonist Anakinra or mice deficient for the inflammasome proteins ASC and NALP3. 4 days and 17 days after crystal injection, mice were sacrificed and knee joints dissected. Histological scoring for synovial inflammation and characterisation of macrophages, neutrophils and T cells were performed. Technetium (Tc) uptake was measured at 6h, 1 and 4 days after OCP injection. Cartilage degradation was evaluated by Safranin O staining and VDIPEN immunohistochemistry. Intra-articular localisation of injected OCP crystals was evidenced by Von Kossa staining.Results: The intra-articular localisation of injected OCP crystals was evidenced by Von Kossa staining performed on non-decalcified samples embedded in methyl-metacrylate. Injection of OCP crystals into knee joints led at day 4 to an inflammatory response with intense macrophage staining and also some neutrophil recruitment in the synovial membrane. This synovitis was not accompanied by increased Tc uptake into the knee joint, Tc uptake being similar in OCP crystal injected knee or control knee at all time points investigated (6h, 1 day, 4 days). The histological modifications persisted over 17 days, with an additional fibrosis evidenced at this later time-point. The OCP crystal-induced synovitis was totally IL-1a and IL-1 independent as shown by the absence of inhibitory effects of anakinra injected into wild-type mice. Accordingly, OCP crystal-induced synovitis was similar in ASC-/- and NALP3-/- mice as no alterations of inflammation were demonstrated between these mice groups. Concerning cartilage matrix degradation, OCP crystals induced a strong breakdown of proteoglycans 4 and 17 days after injection, as measured by loss of red staining from Safranin O-stained sections of cartilage surfaces. In addition, we also measured advanced cartilage matrix destruction mediated by MMPs, as evidenced by VDIPEN staining of cartilage. OCP-mediated cartilage degradation was similar in all experimental conditions tested (WT+Anakinra, or ASC or NALP3 deficient mice).Conclusion: These data indicate in vivo that the intra-articular presence of OCP crystals is associated with cartilage destruction along with synovial inflammation. This is an interesting and new model of destructive arthropathy related to BCP crystals which will allow to assess new therapies in this disease.

Protective effect of intravitreal administration of tresperimus, an immunosuppressive drug, on experimental autoimmune uveoretinitis.

PURPOSE: To test the efficiency of locally administrated tresperimus in experimental autoimmune uveoretinitis (EAU). METHODS: EAU was induced in Lewis rats by S-antigen (S-Ag) immunization. Three intravitreal injections of tresperimus (prevention or prevention/treatment protocols) were performed at different time points after immunization. The pharmacokinetics of tresperimus was evaluated in the ocular tissues and plasma. The in vitro effect of tresperimus was evaluated on macrophages. EAU was graded clinically and histologically. Blood ocular barrier permeability was evaluated by protein concentration in ocular fluids. Immune response to S-Ag was examined by delayed type hypersensitivity, the expression of inflammatory cytokines in lymph nodes, ocular fluids and serum by multiplex ELISA, and in ocular cells by RT-PCR. RESULTS: In vitro, tresperimus significantly reduced the production of inflammatory cytokines by lipopolysaccharide-stimulated macrophages. In vivo, in the treatment protocol, efficient tresperimus levels were measured in the eye but not in the plasma up to 8 days after the last injection. Tresperimus efficiently reduced inflammation, retinal damage, and blood ocular barrier permeability breakdown. It inhibited nitric oxide synthase-2 and nuclear factor κBp65 expression in ocular macrophages. IL-2 and IL-17 were decreased in ocular media, while IL-18 was increased. By contrast, IL-2 and IL-17 levels were not modified in inguinal lymph nodes draining the immunization site. Moreover, cytokine levels in serum and delayed type hypersensitivity to S-Ag were not different in control and treated rats. In the prevention/treatment protocol, ocular immunosuppressive effects were also observed. CONCLUSIONS: Locally administered tresperimus appears to be a potential immunosuppressive agent in the management of intraocular inflammation.

Splenic palpation for the evaluation of morbidity due to schistosomiasis mansoni

This study was undertaken to determine the accuracy of splenic palpation for the diagnosis of splenomegaly, and to determine whether the frequency of individuals with a palpable spleen in an endemic area can be considered as an index of morbidity of schistosomiasis. For the clinical diagnosis of splenomegaly, two criteria have been tested: (A) presence of a palpable spleen and (B) presence of a palpable spleen whose border could be felt more than 4 cm below the costal margin. In an area of high prevalence of the disease (66.3%) 285 individuals aged 18 years or more have been submitted to abdominal ultrasonography and physical examination. Splenomegaly was defined as a splenic length greater than 120 mm by ultrasound and the sensitivity, specificity, positive and negative predictive values of criterion A were 72.2%, 90.5%, 35.1% and 97.8%. The values for criterion B were 27.8%, 98%, 50% and 95%, respectively. In an non endemic area, 517 individuals were submitted to the same protocol and 22 individuals had a palpable spleen, but no patient fulfilled criterion B for splenomegaly, and only one met the ultrasonographic criterion for splenomegaly. The authors concluded that abdominal palpation is a poor method for the diagnosis of splenomegaly.

Glut9 is a major regulator of urate homeostasis and its genetic inactivation induces hyperuricosuria and urate nephropathy.

Elevated plasma urate levels are associated with metabolic, cardiovascular, and renal diseases. Urate may also form crystals, which can be deposited in joints causing gout and in kidney tubules inducing nephrolithiasis. In mice, plasma urate levels are controlled by hepatic breakdown, as well as, by incompletely understood renal processes of reabsorption and secretion. Here, we investigated the role of the recently identified urate transporter, Glut9, in the physiological control of urate homeostasis using mice with systemic or liver-specific inactivation of the Glut9 gene. We show that Glut9 is expressed in the basolateral membrane of hepatocytes and in both apical and basolateral membranes of the distal nephron. Mice with systemic knockout of Glut9 display moderate hyperuricemia, massive hyperuricosuria, and an early-onset nephropathy, characterized by obstructive lithiasis, tubulointerstitial inflammation, and progressive inflammatory fibrosis of the cortex, as well as, mild renal insufficiency. In contrast, liver-specific inactivation of the Glut9 gene in adult mice leads to severe hyperuricemia and hyperuricosuria, in the absence of urate nephropathy or any structural abnormality of the kidney. Together, our data show that Glut9 plays a major role in urate homeostasis by its dual role in urate handling in the kidney and uptake in the liver.

Reversible congestive heart failure associated with primary carnitin deficiency: report of a case and review of the literature.

A 5-year-old previously healthy boy was admitted for abdominal pain and vomiting. Physical examination showed tachypnoe (32/min), hepatomegaly and painful palpation of the upper right abdominal quadrant. Laboratory tests were normal except for elevated ammonium (202mcmol/l). Chest X-ray was performed, showing cardiomegaly and interstitial edema. Transthoracic echocardiography revealed dilated left cavities and LV hypertrophy together with a diffuse hypokinesia and LVEF of 30-40%. Diuretics and ACE-inhibitors were introduced. At that time, the differential diagnosis for the DCM included myocarditis, congenital or genetic, metabolic or autoimmune disease. The next day, the boy underwent cardiac magnetic resonance (CMR) examination, showing a severe dilatation of the LV with an end-diastolic diameter of 50mm and a volume of 150ml. LVEF was 20% with diffuse LV hypokinesia (Fig. 1). No late enhancement was present after Gadolinium injection, ruling out myocarditis. Further laboratory metabolic analysis indicated severely decreased total and free carnitin levels and low renal carnitin reabsorption, corroborating the diagnosis of primary carnitin deficiency (PCD). Carnitin substitution was initiated. The clinical condition rapidly improved. No symptoms of heart failure were present anymore. A follow-up CMR performed 9 months later confirmed the recovery. LV end-diastolic volume decreased from 150ml to 66ml, LVEF increased from 20% to 55% (Fig. 2). Late enhancement was absent after Gadolinum injection (Fig. 3).Carnitin is required for the transport of fatty acids from the cytosol into mitochondria during lipid breakdown. 75% of carnitin is obtained from food, 25% is endogenously synthesized. PCD is an autosomal recessive disorder resulting from impairment of a transporter activity, caused by mutation of the SLC22A5 gene. Incidence is about 1 in 40'000 newborns. Diagnosis is usually made at age 1 to 7. Three forms of PCD are described. In the form associated with cardiomyopathy, the disease is progressive and patient die from heart failure if not treated. Substitution of L-Carnitin leads to a dramatic improvement of disease course.This case underlines the crucial role of etiologic diagnostics in this reversible form of DCM. Early diagnostics and therapy are critical for the prognosis of the patient. This is furthermore an example of a role played by CMR in the diagnostic work-up of heart failure and its follow-up under therapy.

MAP kinase pathways in UV-induced apoptosis of retinal pigment epithelium ARPE19 cells.

The retinal pigment epithelium (RPE) is constantly exposed to external injuries which lead to degeneration, dysfunction or loss of RPE cells. The balance between RPE cells death and proliferation may be responsible for several diseases of the underlying retina, including age-related macular degeneration (AMD) and proliferative vitreoretinopathy (PVR). Signaling pathways able to control cells proliferation or death usually involve the MAPK (mitogen-activated protein kinases) pathways, which modulate the activity of transcription factors by phosphorylation. UV exposure induces DNA breakdown and causes cellular damage through the production of reactive oxygen species (ROS) leading to programmed cell death. In this study, human retinal pigment epithelial cells ARPE19 were exposed to 100 J/m(2) of UV-C and MAPK pathways were studied. We first showed the expression of the three major MAPK pathways. Then we showed that activator protein-1 (AP-1) was activated through phosphorylation of cJun and cFos, induced by JNK and p38, respectively. Specific inhibitors of both kinases decreased their respective activities and phosphorylation of their nuclear targets (cJun and cFos) and reduced UV-induced cell death. The use of specific kinases inhibitors may provide excellent tools to prevent RPE apoptosis specifically in RPE diseases involving ROS and other stress-related compounds such as in AMD.

Scientific mindfulness: A foundation for future themes in international business.

We conceptualize new ways to qualify what themes should dominate the future international business and management (IB/IM) research agenda by examining three questions: Whom should we ask? What should we ask, and which selection criteria should we apply? What are the contextual forces? Our main findings are the following: (1) wider perspectives from academia and practice would benefit both rigor and relevance; (2) four key forces are climate change, globalization, inequality, and sustainability; and (3) we propose scientific mindfulness as the way forward for generating themes in IB/IM research. Scientific mindfulness is a holistic, cross-disciplinary, and contextual approach, whereby researchers need to make sense of multiple perspectives with the betterment of society as the ultimate criterion.

A cross-cultural study of the higher-order structures underlying personality disorders in French-speaking Africa and Switzerland

Most studies about the higher-order dimensions to be considered in order to parsimoniously describe Personality Disorders (PDs) have identified between two and four factors but there is still no consensus about their exact number. In this context, the cultural stability of these structures might be a criterion to be considered. The aim of this study was to identify stable higher-order structures of PD traits in a French-speaking African and Swiss sample (N = 2,711). All subject completed the IPDE screening questionnaire. Using Everett's criterion and conducting a series of principal component analyses, a cross-culturally stable two- and four-factor structure were identified, associated with a total congruence coefficient of respectively .98 and .94 after Procrustes rotation. Moreover, these two structures were also highly replicable across the four African regions considered, North Africa, West Africa, Central Africa, and Mauritius, with a mean total congruence coefficient of respectively .97 and .87. The four-factor structure presented the advantage of being similar to Livesely's four components and of describing the ten PDs more accurately.

Delayed mortality and attenuated thrombocytopenia associated with severe malaria in urokinase- and urokinase receptor-deficient mice.

We explored the role of urokinase and tissue-type plasminogen activators (uPA and tPA), as well as the uPA receptor (uPAR; CD87) in mouse severe malaria (SM), using genetically deficient (-/-) mice. The mortality resulting from Plasmodium berghei ANKA infection was delayed in uPA(-/-) and uPAR(-/-) mice but was similar to that of the wild type (+/+) in tPA(-/-) mice. Parasitemia levels were similar in uPA(-/-), uPAR(-/-), and +/+ mice. Production of tumor necrosis factor, as judged from the plasma level and the mRNA levels in brain and lung, was markedly increased by infection in both +/+ and uPAR(-/-) mice. Breakdown of the blood-brain barrier, as evidenced by the leakage of Evans Blue, was similar in +/+ and uPAR(-/-) mice. SM was associated with a profound thrombocytopenia, which was attenuated in uPA(-/-) and uPAR(-/-) mice. Administration of aprotinin, a plasmin antagonist, also delayed mortality and attenuated thrombocytopenia. Platelet trapping in cerebral venules or alveolar capillaries was evident in +/+ mice but absent in uPAR(-/-) mice. In contrast, macrophage sequestration in cerebral venules or alveolar capillaries was evident in both +/+ and uPAR(-/-) mice. Polymorphonuclear leukocyte sequestration in alveolar capillaries was similar in +/+ and uPAR(-/-) mice. These results demonstrate that the uPAR deficiency attenuates the severity of SM, probably by its important role in platelet kinetics and trapping. These results therefore suggest that platelet sequestration contributes to the pathogenesis of SM.

Obesity markers and estimated 10-year fatal cardiovascular risk in Switzerland.

BACKGROUND AND AIM: There is an ongoing debate on which obesity marker better predicts cardiovascular disease (CVD). In this study, the relationships between obesity markers and high (>5%) 10-year risk of fatal CVD were assessed. METHODS AND RESULTS: A cross-sectional study was conducted including 3047 women and 2689 men aged 35-75years. Body fat percentage was assessed by tetrapolar bioimpedance. CVD risk was assessed using the SCORE risk function and gender- and age-specific cut points for body fat were derived. The diagnostic accuracy of each obesity marker was evaluated through receiver operating characteristics (ROC) analysis. In men, body fat presented a higher correlation (r=0.31) with 10-year CVD risk than waist/hip ratio (WHR, r=0.22), waist (r=0.22) or BMI (r=0.19); the corresponding values in women were 0.18, 0.15, 0.11 and 0.05, respectively (all p<0.05). In both genders, body fat showed the highest area under the ROC curve (AUC): in men, the AUC (95% confidence interval) were 76.0 (73.8-78.2), 67.3 (64.6-69.9), 65.8 (63.1-68.5) and 60.6 (57.9-63.5) for body fat, WHR, waist and BMI, respectively. In women, the corresponding values were 72.3 (69.2-75.3), 66.6 (63.1-70.2), 64.1 (60.6-67.6) and 58.8 (55.2-62.4). The use of the body fat percentage criterion enabled the capture of three times more subjects with high CVD risk than the BMI criterion, and almost twice as much as the WHR criterion. CONCLUSION: Obesity defined by body fat percentage is more related with 10-year risk of fatal CVD than obesity markers based on WHR, waist or BMI.

Fills adolescents de famílies amb dinàmiques violentes: Afectació i repercussions. Una perspectiva des del SATAF

S’estableix una comparativa entre adolescents provinents de famílies amb dinàmiques de violència i adolescents immersos en dinàmiques no-violentes, emprant el MACI i una graella construïda segons criteri tècnic. Malgrat el petit tamany mostral s’obtenen dades d’interès clínic referides als adolescents VIDO.