Characterization of protective and non-protective surface membrane carbohydrate epitopes of Schistosoma mansoni

We have produced a number of monoclonal antibodies, protective and non-protective, which recognize a complex of schistosomula antigens, including the 38 kDa antigen. Eight different protective and non-protective monoclonal antibodies, varying in isotypes, were used in the binding assays. Lectin inhibition studies suggested that the monoclonal antibodies probably recognized carbohydrate epitopes on the antigen(s). Immunoprecipitation studies showed that at least two of the monoclonal antibodies recognized different epitopes on the same molecule. Additionally, we tested for monoclonal antibody binding after the antigens were treated with; 1) proteases, 2) periodate, 3) various exo- and endoglycosidases, 4) mild acid hydrolysis. We also tested for binding of the antibodies to keyhole limpet hemocyanin (KLH). Using the 8 monoclonal antibodies as probes, we were able to define at least 4 different carbohydrate epitopes related to the protective monoclonal antibodies, and at least one epitope which is seen by the non-protective antibodies. The epitope seen by the non-protective antibodies was shown to be cross-reactive with epitopes on KLH. These results demonstrate the importance of epitope mapping studies for any defined vaccine.

NEUROPATHOPHYSIOLOGICAL MECHANISMS IN GLUTARIC ACIDURIA TYPE I: 3-HYDROXYGLUTARIC ACID LEADS TO AMMONIA INCREASE AND NON-APOPTOTIC CELL DEATH

A 3D in vitro model of rat organotypic brain cell cultures in aggregates was used to investigate neurotoxicity mechanisms in glutaric aciduria type I (GA-I). 1 mM glutarate (GA) or 3-hydroxyglutarate (3OHGA) were repeatedly added to the culture media at two different time points. In cultures treated with 3OHGA, we observed an increase in lactate in the medium, pointing to a possible inhibition of Krebs cycle and respiratory chain. We further observed that 3OHGA and to a lesser extend GA induced an increase in ammonia production with concomitant decrease of glutamine concentrations, which may suggest an inhibition of the astrocytic enzyme glutamine synthetase. These previously unreported findings may uncover a pathogenic mechanism in this disease which has deleterious effects on early stages of brain development. By immunohistochemistry we showed that 3OHGA increased non-apoptotic cell death. On the cellular level, 3OHGA and to a lesser extend GA led to cell swelling and loss of astrocytic fibers whereas a loss of oligodendrocytes was only observed for 3OHGA. We conclude that 3OHGAwas the most toxic metabolite in our model for GA-I. 3OHGA induced deleterious effects on glial cells, an increase of ammonia production, and resulted in accentuated cell death of non-apoptotic origin.

Sentinel nodes and and non sentinel nodes evaluation in T1 melanoma patients

Objective: Because increasing incidence of melanoma and dermatologicsystematic screening, more early superficial melanoma are discovered in Switzerland. Patients with Breslow index more than 1 mm. (T2) represent the classical indication to sentinel node (SN). It has been shown that some ''risky'' T1 patients may have micrometastatic SNs. T1b melanoma are defined by presence of ulceration,Clark IV (ormore) level, signs of melanoma regression (old classification) and high mitotic index (new TNM). The objective of the present study was to review the incidence and risk for metastatic SN in T1 patients and if radical lymph node dissection is justified (evaluation of non sentinel node [NSN]) compared with T2-4 patients.Methods: Retrospective review of a cohort of all patients operated for T1-4 clinically N0 and radiological M0 melanoma patients between 1997 and 2010 in a reference melanoma centre.Results: 599 melanoma patients have been operated with SNdissection. There were 98 T1 patients. Metastatic SN were observed in 2 out of 24 T1a patients and in 5 out of 74 T1b patients. This means overall 7% T1 patients were at least N1a. None of SN+ T1a or T1b patients had metastatic NSN after radical lymph node dissections (RLND). During the follow-up (1998-2010), no patients presented with locoregional disease and only one T1a N1a patient died of metastatic melanoma. These results contrast with the other 591 T2-4 patients: 150 were SN+ (25%) and among them 23 had metastatic NSN after RLND. Overall 23/136 (17%) had metastatic NSN.Conclusion: T1 melanoma patients are at significant risk (7%) for metastatic lymph node in the corresponding drainage basin. T1a and T1b did not differ regarding this risk. However, the benefit for a RLND must be reevaluated regarding surgical morbidity, because none of T1 patients had metastatic NSN.

Is the consumption-income ratio stationary? Evidence from linear and nonlinear panel unit root tests for OECD and non-OECD countries

This paper applies recently developed heterogeneous nonlinear and linear panel unit root tests that account for cross-sectional dependence to 24 OECD and 33 non-OECD countries’ consumption-income ratios over the period 1951–2003. We apply a recently developed methodology that facilitates the use of panel tests to identify which individual cross-sectional units are stationary and which are nonstationary. This extends evidence provided in the recent literature to consider both linear and nonlinear adjustment in panel unit root tests, to address the issue of cross-sectional dependence, and to substantially expand both time-series and cross sectional dimensions of the data analysed. We find that the majority (65%) of the series are nonstationary with slightly fewer OECD countries’ (61%) series exhibiting a unit root than non-OECD countries (68%).

Quasiconformal maps, analytic capacity, and non linear potentials

"Vegeu el resum a l'inici del document del fitxer adjunt."

Kinetics of antigen specific and non-specific polyclonal B-cell responses during lethal Plasmodium yoelii malaria

In order to study the kinetics and composition of the polyclonal B-cell activation associated to malaria infection, antigen-specific and non-specific B-cell responses were evaluated in the spleens of mice infected with Plasmodium yoelii 17 XL or injected with lysed erythrocytes or plasma from P. yoelii infected mice or with P. falciparum culture supernatants. Spleen/body weigth ratio, numbers of nucleated spleen cells and Immunoglobulin-containing and Immunoglobulin-secreting cells increased progressively during the course of infection,in parallel to the parasitemia. A different pattern of kinetics was observed when anti-sheep red blood cell and anti-trinitrophenylated-sheep red blood cell plaque forming cells response were studied: maximum values were observed at early stages of infection, whereas the number of total Immunoglobulin-containing and Immunoglobulin-secreting cells were not yet altered. Conversely, at the end of infection, when these latter values reached their maximum, the anti-sheep red blood cell and anti-trinitrophenylated-sheep red blood cell specific responses were normal or even infranormal. In mice injected with Plasmodium-derived material, a higher increase in antigen-specific PFC was observed, as compared to the increase of Immunoglobulin-containing and Immunoglobulin-secreting cell numbers. This suggested a "preferential" (antigen-plus mitogen-induced) stimulation of antigen-specific cells rather than a generalized non-specific (mitogen-induced) triggering of B-lymphocytes. On the basis of these and previous results, it is suggested that polyclonal B-cell activation that takes place during the course of infection appears as a result of successive waves of antigen-specific B-cell activation.

Dengue 2 virus enhancement in asthmatic and non asthmatic individual

During the 1981 dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) Cuban epidemic, bronchial asthma (BA) was frequently found as a personal or family antecedent in dengue hemorragic fever patients. Considering that antibody dependent enhancement (ADE) plays an important role in the etiopathogenic mechanism of DHF/DSS, we decide to study the Dengue 2 virus (D2V) capability of replication in peripheral blood leukocytes (PBL) from asthmatic patients and healthy persons. In 90% of asthmatic patients and 53.8% of control group it was obtained PBL with a significant D2V enhancing activity (X² p < 0.01). Power enhancement was higher in asthmatic group. This is the first in vitro study relating BA and the dengue 2 virus immuno enhancement. The results obtained support the role of BA as a risk factor for DHF/DSS as already described on epidemiological data.

Unexpectedly late expression of intracellular CD3epsilon and TCR gammadelta proteins during adult thymus development.

During adult thymus development immature CD4(-)CD8(-) [double-negative (DN)] precursor cells pass through four phenotypically distinct stages defined by expression of CD44 and CD25: CD44(hi)CD25(-) (DN1), CD44(hi)CD25(+) (DN2), CD44(lo)CD25(+) (DN3) and CD44(lo)CD25(-) (DN4). Although it is well established that the TCR beta, gamma and delta genes are rearranged and expressed in association with the CD3 components in DN thymocytes, the precise timing of expression of the TCR and CD3 proteins has not been determined. In this report we have utilized a sensitive intracellular (ic) staining technique to analyze the expression of ic CD3epsilon, TCR beta and TCR gammadelta proteins in immature DN subsets. As expected from previous studies of TCR beta rearrangement and mRNA expression, icTCR beta(+) cells were first detected in the DN3 subset and their proportion increased thereafter. Surprisingly, however, both icCD3epsilon(+) and icTCR gammadelta(+) cells were detected at later stages of development than was predicted by molecular studies. In particular icCD3epsilon protein expression coincided with the transition from the DN2 to DN3 stage of development, whereas icTCR gammadelta protein expression was only detected in a minor subset of DN4 cells. The implications of these findings for alphabeta lineage divergence will be discussed.

T cell responses to repeat and non-repeat regions of the circumsporozoite protein detected in volunteers immunized with Plasmodium falciparum sporozoites

The design of malarial vaccine based on the circumsporozoite (CS) protein, a majuor surface antigen of the sporozoite stage of the malaria parasite, requires the identification of T and B cell epitopes for inclusion in recombinant or synthetic vaccine candidates. We have investigated the specificity and function of a series of T cell clones, derived from volunteers immunized with Plasmodium falciparum sporozoites in an effort to identify relevant epitopes in the immune response to the pre-erythrocytic stages of the parasite. CD4+ T cell clones were obtained wich specifically recognized a repetitive epitope located in the 5'repeat region of the CS protein. This epitope, when conjugated to the 3'repeat region in a synthetic MAPs construct, induced high titers of antisporozoite antibodies in C57B1 mice. A second T cell epitope, which mapped to aa 326-345 of the carboxy terminal, was recognized by lytic, as well as non-lytic, CD4+ T cells derived from the sporozoite-immunized volunteers. The demonstration of CD4+ CTL in the volunteers, and the recent studies inthe rodent model (Renia et al., 1991; Tsuji et al., 1990), suggested that CS-specific CD4+ T cells, in addition to their indirect role as helper cells in the induction of antibody and CD8 + effector cells, may also play a direct role in protection against sporozoite challenge by targeting EEF within the liver.

An Introduction to parametric and non-parametric models for bivariate positive insurance claim severity distributions

We present a real data set of claims amounts where costs related to damage are recorded separately from those related to medical expenses. Only claims with positive costs are considered here. Two approaches to density estimation are presented: a classical parametric and a semi-parametric method, based on transformation kernel density estimation. We explore the data set with standard univariate methods. We also propose ways to select the bandwidth and transformation parameters in the univariate case based on Bayesian methods. We indicate how to compare the results of alternative methods both looking at the shape of the overall density domain and exploring the density estimates in the right tail.

Effect of magnesium chloride and guanidinum chloride on the extraction of components of extracellular matrix from chicken cartilage

In order to evaluate the effect of chaotropic agents on proteoglycan and non-collagenous proteins, chicken xiphoid cartilage was treated with guanidine-HCI and MgCl2 in different concentrations (1M to 5M), and different periods of time (12, 24, 48 and 72hr). The maximum yield of uronic acid was obtained with 3M MgCl2 (73.3 per cent). Concentrations of 4M and 5M of MgCl2 showed that much less uronic acid was removed, 55.3 per cent and 38.1 respectively. Extraction with 3M MgCl2 and 3M guanidine-HCl resulted better efficiency when performed for 48 hr. Analysis by SDS-PAGE of the extracts obtained with guanidine-HCl and MgCl, in different concentrations pointed out that most components are equally removed with the two solvents, showing that the extraction with MgCl2 is an alternative assay to remove non-collagenous proteins from extracellular matrix.

An epidemiological and clinical approach to adolescent suicide. A comparison between suicidal and non-suicidal clinical groups in a health foundation center for French students.

Suicidal behaviour among young people represents a major public health problem. This study seeks to compare the major sociological, clinical, schooling and family features of suicidal and non-suicidal subgroups of adolescents hospitalised in the Health Foundation Center for French Students of neufmoutiers en Brie (France). All these adolescents suffered from the severe mental disorders. The adolescents from the suicidal subgroup presented significantly fewer psychoses and more mood disorders than those of the non-suicidal subgroup. Half of the patients from the suicidal subgroup presented some features of personality disorders, mostly borderline personality disorders. Nevertheless, their global functioning was more frequently improved between admission and discharge than was the case for the non-suicidal group.

A Comparison of Two Brazilian Populations of Culex quinquefasciatus (Say, 1823) from Endemic and Non-endemic Areas to Infection with Wuchereria bancrofti (Cobbold, 1877)

Culex quinquefasciatus is known to be an efficient insect host of Wuchereria bancrofti. In Brazil Cx. quinquefasciatus is widely distributed throughout the country and is often abundant in and around human habitations. In contrast, Bancroftian filariasis is limited to three foci in Brazil. Experiments were undertaken to compare the vector capacities of Cx. quinquefasciatus originating from Maceió (Alagoas), one of the endemic areas of W. bancrofti infection in Brazil, and Belo Horizonte (Minas Gerais), a non endemic area. Laboratory-reared Cx. quinquefasciatus were dissected 20 days after blood feeding on microfilaraemic patients. Survival rates and the number of infective larvae that developed did not differ in female mosquitoes of different origins. Thus both populations of Culex were susceptible to infection with W. bancrofti