Calibration standars of nuclear microprobes

El Micro-haz de iones Pesados (MiP) del laboratorio Tandar constituye un instrumento de características únicas en el país, pues puede proveer haces de iones pesados de dimensiones micrométricas acelerados hasta decenas de MeV de energía. La búsqueda de tamaños de haz más pequeños ha creado la necesidad de contar con estándares de calibración de elevada calidad de resolución. En el presente trabajo se desarrollaron los primeros prototipos para calibrar la focalización del haz: estructuras metálicas de cobre o niquel en forma de grilla con orificios cuadrados. Se emplearon dos métodos de fabricación. En el primero se utilizaron técnicas de fotolitografía convencional sobre un sustrato de silicio con foto-resina, mientras que en el segundo se utilizó el MiP para micro-mecanizar sustratos de Niobato de Litio (LiNbO3). En ambos casos se finalizó el proceso de fabricación del patrón con electrodeposición de cobre o níquel sobre la matriz desarrollada. Mediante la técnica fotolitográfica se fabricaron grillas de níquel que varían entre 130 y 180 mesh**. Mediante micro-mecanizado con el MiP se fabricaron grillas de cobre de entre 500 y 2000 mesh sobre sustratos de LiNbO3.The Micro-heavy ion beam (MiP) at Tandar’s Lab is a unique instrument in the country, as it can provide heavy ion beams at micrometer-scale accelerated to tens of MeV energy. The quest for smaller beam sizes has created the need for calibration standards of high resolution quality. In this paper we developed the first prototypes to calibrate the beam focusing: metal structures of copper or nickel shaped grid with square holes. We used two methods of manufacture. Were used in the first conventional photolithography techniques on a silicon substrate with photoresin while the second was used for micromachining with MiP substrates of lithium niobate (LiNbO3). In both cases the process for the manufacture was finished with electro-deposition of copper or nickel on the matrix developed. By photolithographic technique nickel grids were manufactured varying between 130 and 180 mesh. By MiP micromachining copper grids were produced between 500 and 2000 mesh on LiNbO3 substrates.Fil: Arena, S.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Faya, T.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Lell, J.. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; ArgentinaFil: Vega, N.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Davidson, Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nesprias, Francisco Jose Gabriel. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Debray, M.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentin

A longitudinal study of allergy and intestinal helminth infections in semi urban and rural areas of Flores, Indonesia (ImmunoSPIN Study)

BACKGROUND: The prevalence of asthma and atopic disease has been reported to be low in low income countries, however helminth infections are likely to be high among these communities. The question of whether helminth infections play a role in allergic diseases can best be addressed by intervention studies. None of the studies so far have been based on a large scale placebo-controlled trial. METHOD/DESIGN: This study was designed to assess how intestinal helminth infections can influence the immune response and atopic and allergic disorders in children in Indonesia. The relations between allergic outcomes and infection and lifestyle factors will be addressed. This study was set up among school-age children in semi urban and rural areas, located in Ende District of Flores Island, Indonesia. A randomized placebo-controlled anthelmintic treatment trial to elucidate the impact of helminth infections on the prevalence of skin prick test (SPT) reactivity and symptoms of allergic diseases will be performed. The children living in these semi-urban and rural areas will be assessed for SPT to allergens before and after 1 and 2 years of treatment as the primary outcome of the study; the secondary outcome is symptoms (asthma and atopic dermatitis); while the tertiary outcome is immune responses (both antibody levels to allergens and cellular immune responses). DISCUSSION: The study will provide information on the influence of helminth infections and anthelmintic treatment on immune response, atopy and allergic disorders. TRIAL REGISTRATION: Current Controlled Trials ISRCTN: ISRCTN8383081

Socio-economic status is inversely related to bed net use in Gabon

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NCF1 gene and pseudogene pattern: association with parasitic infection and autoimmunity

<p>Abstract</p> <p>Background</p> <p>Neutrophil cytosolic factor 1, p47^phox(NCF1) is a component of the leukocyte NADPH oxidase complex mediating formation of reactive oxygen intermediates (ROI) which play an important role in host defense and autoimmunity. An individual genomic pattern of <it>ncf1 </it>and its two types of pseudogenes (reflected by the ΔGT/GTGT ratio) may influence the individual capacity to produce ROI.</p> <p>Methods</p> <p>NCF1ΔGT/GTGT ratios were correlated with clinical parameters and ROI production during <it>Plasmodium falciparum </it>malaria and with susceptibility to the autoimmune disease multiple sclerosis (MS).</p> <p>Results</p> <p>Among Gabonese children with severe malaria, ROI production from peripheral blood tended to be higher in individuals with a ΔGT/GTGT ratio ≤ 1:1. ΔGT/GTGT ratios were not associated with susceptibility to MS, but to age-of-onset among MS patients.</p> <p>Conclusion</p> <p>The genomic pattern of <it>NCF1 </it>and its pseudogenes might influence ROI production but only marginally influence susceptibility to and outcome of malaria and MS.</p

High-pitch dual-source CT angiography of the aortic valve-aortic root complex without ECG-synchronization.

PURPOSE: To compare image quality and radiation dose of high-pitch computed tomography angiography(CTA) of the aortic valve-aortic root complex with and without prospective ECG-gating compared to a retrospectively ECG-gated standard-pitch acquisition. MATERIALS AND METHODS: 120 patients(mean age 68 +/- 13 years) were examined using a 128-slice dual-source CT system using prospectively ECG-gated high-pitch(group A; n = 40), non-ECG-gated high-pitch(group B; n = 40) or retrospectively ECG-gated standard-pitch(C; n = 40) acquisition techniques. Image quality of the aortic root, valve and ascending aorta including the coronary ostia was assessed by two independent readers. Image noise was measured, radiation dose estimates were calculated. RESULTS: Interobserver agreement was good(kappa = 0.64-0.78). Image quality was diagnostic in 38/40 patients(group A), 37/40(B) and 38/40(C) with no significant difference in number of patients with diagnostic image quality among all groups (p = 0.56). Significantly more patients showed excellent image quality in group A compared to groups B and C(each, p < 0.01). Average image noise was significantly different between all groups(p < 0.05). Mean radiation dose estimates in groups A and B(each; 2.4 +/- 0.3 mSv) were significantly lower compared to group C(17.5 +/- 4.4 mSv; p < 0.01). CONCLUSION: High-pitch dual-source CTA provides diagnostic image quality of the aortic valve-aortic root complex even without ECG-gating at 86% less radiation dose when compared to a standard-pitch ECG-gated acquisition

Kawasaki disease: a review with emphasis on cardiovascular complications

Kawasaki disease (KD) is an acute systemic vasculitis that is currently the leading cause of acquired heart disease in childhood in the United States. Cardiovascular complications are the major cause of morbidity, are responsible for virtually all deaths from KD and should be evaluated as soon as possible after the acute phase to establish the baseline status, in order to predict disease progression and determine adequate treatment. In selected patients, electrocardiography (ECG)-gated cardiac computed tomography (CT) and magnetic resonance (MR) imaging are valuable non-invasive techniques that can be used to help diagnose the cardiovascular complications associated with KD. In this article, we review the epidemiology, aetiology and pathogenesis, histopathology, clinical features, cardiovascular complications and imaging, focusing on the role of cardiac CT and MR on the initial assessment and follow-up of the cardiovascular complications of KD

Impact of Plasmodium falciparum infection on the frequency of moderate to severe anaemia in children below 10 years of age in Gabon

BACKGROUND: Improving the understanding of childhood malarial anaemia may help in the design of appropriate management strategies. METHODS: A prospective observational study over a two-year period to assess the burden of anaemia and its relationship to Plasmodium falciparum infection and age was conducted in 8,195 febrile Gabonese children. RESULTS: The proportion of children with anaemia was 83.6% (n = 6830), higher in children between the ages of six and 23 months. Those under three years old were more likely to develop moderate to severe anaemia (68%). The prevalence of malaria was 42.7% and P. falciparum infection was more frequent in children aged 36-47 months (54.5%). The proportion of anaemic children increased with parasite density (p 60%), but was unrelated to P. falciparum parasitaemia. CONCLUSION: Malaria is one of the main risk factors for childhood anaemia which represents a public health problem in Gabon. The risk of severe malarial anaemia increases up the age of three years. Efforts to improve strategies for controlling anaemia and malaria are needed

Induction of Plasmodium falciparum-Specific CD4+ T Cells and Memory B Cells in Gabonese Children Vaccinated with RTS,S/AS01E and RTS,S/AS02D

The recombinant circumsporozoite protein (CS) based vaccine, RTS,S, confers protection against Plasmodium falciparum infection in controlled challenge trials and in field studies. The RTS,S recombinant antigen has been formulated with two adjuvant systems, AS01 and AS02, which have both been shown to induce strong specific antibody responses and CD4 T cell responses in adults. As infants and young children are particularly susceptible to malaria infection and constitute the main target population for a malaria vaccine, we have evaluated the induction of adaptive immune responses in young children living in malaria endemic regions following vaccination with RTS,S/AS01(E) and RTS,S/AS02(D). Our data show that a CS-specific memory B cell response is induced one month after the second and third vaccine dose and that CS-specific antibodies and memory B cells persist up to 12 months after the last vaccine injection. Both formulations also induced low but significant amounts of CS-specific IL-2(+) CD4(+) T cells one month after the second and third vaccine dose, upon short-term in vitro stimulation of whole blood cells with peptides covering the entire CS derived sequence in RTS,S. These results provide evidence that both RTS,S/AS01(E) and RTS,S/AS02(D) induced adaptive immune responses including antibodies, circulating memory B cells and CD4(+) T cells directed against P. falciparum CS protein.ClinicalTrials.gov NCT00307021

Genetic polymorphisms and susceptibility to lung disease

Susceptibility to infection by bacterium such as Bacillus anthracis has a genetic basis in mice and may also have a genetic basis in humans. In the limited human cases of inhalation anthrax, studies suggest that not all individuals exposed to anthrax spores were infected, but rather, individuals with underlying lung disease, particularly asthma, sarcoidosis and tuberculosis, might be more susceptible. In this study, we determined if polymorphisms in genes important in innate immunity are associated with increased susceptibility to infectious and non-infectious lung diseases, particularly tuberculosis and sarcoidosis, respectively, and therefore might be a risk factor for inhalation anthrax. Examination of 45 non-synonymous polymorphisms in ten genes: p47phox (NCF1), p67phox (NCF2), p40phox (NCF4), p22phox (CYBA), gp91phox (CYBB), DUOX1, DUOX2, TLR2, TLR9 and alpha 1-antitrypsin (AAT) in a cohort of 95 lung disease individuals and 95 control individuals did not show an association of these polymorphisms with increased susceptibility to lung disease