Measurement of the ν_{e}-Nucleus Charged-Current Double-Differential Cross Section at ⟨E_{ν}⟩=2.4 GeV Using NOvA.

The inclusive electron neutrino charged-current cross section is measured in the NOvA near detector using 8.02×10^{20} protons-on-target in the NuMI beam. The sample of GeV electron neutrino interactions is the largest analyzed to date and is limited by ≃17% systematic rather than the ≃7.4% statistical uncertainties. The double-differential cross section in final-state electron energy and angle is presented for the first time, together with the single-differential dependence on Q^{2} (squared four-momentum transfer) and energy, in the range 1 GeV≤E_{ν}<6 GeV. Detailed comparisons are made to the predictions of the GENIE, GiBUU, NEUT, and NuWro neutrino event generators. The data do not strongly favor a model over the others consistently across all three cross sections measured, though some models have especially good or poor agreement in the single differential cross section vs Q^{2}.

Search for Active-Sterile Antineutrino Mixing Using Neutral-Current Interactions with the NOvA Experiment.

This Letter reports results from the first long-baseline search for sterile antineutrinos mixing in an accelerator-based antineutrino-dominated beam. The rate of neutral-current interactions in the two NOvA detectors, at distances of 1 and 810 km from the beam source, is analyzed using an exposure of 12.51×10^{20} protons-on-target from the NuMI beam at Fermilab running in antineutrino mode. A total of 121 of neutral-current candidates are observed at the far detector, compared to a prediction of 122±11(stat.)±15(syst.) assuming mixing only between three active flavors. No evidence for ν[over ¯]_{µ}→ν[over ¯]_{s} oscillation is observed. Interpreting this result within a 3+1 model, constraints are placed on the mixing angles θ_{24}<25° and θ_{34}<32° at the 90% C.L. for 0.05 eV^{2}≤Δm_{41}^{2}≤0.5 eV^{2}, the range of mass splittings that produces no significant oscillations at the near detector. These are the first 3+1 confidence limits set using long-baseline accelerator antineutrinos.

Cellular organization and appearance of differentiated structures in developing stages of the parasitic platyhelminth Echinococcus granulosus.

Echinococcus granulosus is the causative agent of hydatidosis, a major zoonoses that affects humans and herbivorous domestic animals. The disease is caused by the pressure exerted on viscera by hydatid cysts that are formed upon ingestion of E. granulosus eggs excreted by canine. Protoscoleces, larval forms infective to canine, develop asynchronously and clonally from the germinal layer (GL) of hydatid cysts. In this report, we describe the cellular organization and the appearance of differentiated structures both in nascent buds and developed protoscoleces attached to the GL. Early protoscolex morphogenesis is a highly complex and dynamic process starting from the constitution of a foramen in the early bud, around which nuclei are distributed mainly at the lateral and apical regions. Similarly, distribution of nuclei in mature protoscoleces is not homogenous but underlies three cellular territories: the suckers, the rostellar pad, and the body, that surrounds the foramen. Several nuclei are associated to calcareous corpuscles (Cc), differentiated structures that are absent in the earlier bud stages. The number of nuclei is similar from the grown, elongated bud stage to the mature protoscolex attached to the GL, strongly suggesting that there is no significant cellular proliferation during final protoscolex development. The amount of DNA per nucleus is in the same range to the one described for most other platyhelminthes. Our results point to a sequential series of events involving cell proliferation, spatial cell organization, and differentiation, starting in early buds at the GL of fertile hydatid cysts leading to mature protoscoleces infective to canine.

Binding properties of Echinococcus granulosus fatty acid binding protein.

EgFABP1 is a developmentally regulated intracellular fatty acid binding protein characterized in the larval stage of parasitic platyhelminth Echinococcus granulosus. It is structurally related to the heart group of fatty acid binding proteins (H-FABPs). Binding properties and ligand affinity of recombinant EgFABP1 were determined by fluorescence spectroscopy using cis- and trans-parinaric acid. Two binding sites for cis- and trans-parinaric acid were found (K(d(1)) 24+/-4 nM, K(d(2)) 510+/-60 nM for cis-parinaric acid and K(d(1)) 32+/-4 nM, K(d(2)) 364+/-75 nM for trans-parinaric). A putative third site for both fatty acids is discussed. Binding preferences were determined using displacement assays. Arachidonic and oleic acids presented the highest displacement percentages for EgFABP1. The Echinococcus FABP is the unique member of the H-FABP group able to bind two long chain fatty acid molecules with high affinity. Structure-function relationships and putative roles for EgFABP1 in E. granulosus metabolism are discussed.

Characterisation of the proximal regulatory domain of the Echinococcus granulosus homeodomain-containing gene EgHbx1.

In an attempt to understand the molecular basis of the development of Echinococcus granulosus, we have previously isolated several homeobox-containing genes (EgHbx1-5). Here we report the characterisation of the EgHbx1 proximal regulatory domain. EgHbx1 codes for an amino acid sequence presenting 90% identity at the homeodomain level with the Drosophila melanogaster NK1-S59 transcription factor. The proximal regulatory domain sequence and the transcription start site were determined. Electrophoretic mobility shift assays using nuclear extracts from protoscoleces revealed the presence of specific DNA-protein complexes. These results constitute a hint and provide new tools to decipher regulatory cascades during E. granulosus development.

Effect of praziquantel on the strobilar development of Mesocestoides corti in vitro.

The effect of praziquantel (PZQ) on the strobilar development of the cyclophyllidean cestode Mesocestoides corti was explored. Mesocestoides corti larvae were cultivated under conditions reported to favour their differentiation to the adult stage. Parasites were exposed to 0.1 microg ml(-1) PZQ for 16 h and subsequently transferred to drug-free medium. The ocurrence of segmentation--an early event of the larval somatic differentiation to the adult worm-- was considered as quantitative data. This phenomenon was evidenced earlier in worms transiently exposed to PZQ with respect to control cultures. Moreover, the rate of segmentation of drug-treated worms at the end of the experiment almost doubled that of control worms. To date, no similar effect on any cestode developmental process has been reported for an anthelmintic drug. In the light of the existing knowledge and understanding of PZQ mechanisms of action, the proposed experimental approach could contribute to the elucidation of pathways and mechanisms involved in cestode strobilar development.

Molecular cloning and characterization of a thioredoxin gene from Echinococcus granulosus.

The insert of a clone from a lambdagt11 Echinococcus granulosus (Platyhelminth, Cestoda) protoscolex cDNA library, showed an open reading frame whose deduced protein sequence presents a high homology with all described thioredoxins (TRX). The TRX active site (Trp-Cys-Gly-Pro-Cys) is completely conserved. With a monospecific antibody, selected from a total anti-protoscolex sera by the isolated clone, a 12 kDa polypeptide was immunoprecipitated from a protoscolex total protein extract. Furthermore, an antiserum raised against a recombinant EgTRX also recognizes a 12 kDa band in these extracts. The recombinant protein presents TRX activity, using the insulin reduction assay. Finally, a TRX activity was characterized in protoscolex extracts. In all organisms where TRXs were studied, they participate in a cascade of redox exchanges, contributing to the maintaining of cell homeostasis. Considering that the parasitic flatworm E. granulosus is probably submitted to an important oxidative stress due to host defences, EgTRX protein could be involved in the survival strategies of this parasite.

The effect of hypoglycemic seizures on cognitive function in children with diabetes: a 7-year prospective study.

Sixteen children with insulin-dependent diabetes mellitus were evaluated at diagnosis and after 1, 3, and 7 years. They showed significant declines in verbal but not visuospatial abilities, particularly if they had any seizures from hypoglycemia. At the 7-year assessment those with hypoglycemic seizures showed deficits on perceptual, motor, memory, and attention tasks.

Echinococcus granulosus: preparation of protein extracts from protoscolex nuclei for mobility-shift assays.

Nuclei from Echinococcus granulosus protoscolices were isolated from infected sheep. Protein extracts were prepared for analysis of DNA-protein interactions involving specific transcriptional regulatory factors. Gel mobility-shift assays were done using a heterologous probe containing binding sites for widespread transcription factors. A fragment of the promoter of GATA-1 transcription factor from the chicken was selected. When nuclear extracts from E. granulosus protoscolices were assayed a specific band shift was observed. The methodologies developed in this study could provide an important contribution for the characterization of the DNA-protein interactions involved in transcriptional regulation within the context of recent developments in the molecular biology of this parasite.

Remarks on the phylogeny and structure of fatty acid binding proteins from parasitic platyhelminths.

Four fatty acid binding proteins (FABPs) have been described in 4 parasitic platyhelminths: Schistosoma mansoni, Schistosoma japonicum, Fasciola hepatica and Echinococcus granulosus. FABPs form a multigenic family of cytosolic proteins widely distributed in metazoan tissues, the function of which is still poorly understood. These helminth proteins have recently received attention, since there are reports to indicate that S. mansoni and F. hepatica FABPs may be protective antigens. In addition, these proteins could play a major role in the parasites' life-cycles because platyhelminths are unable to synthesize de novo most of their lipids. We have undertaken phylogenetic and structural analyses of platyhelminth FABPs in an attempt to characterize features of biological relevance. Phylogenetically, these FABPs appear to be more closely related to those of vertebrate heart, mammary gland, muscle, retina, skin, brain and myelin, although no clear functional relationships were established between them. We describe several conserved motifs characteristic of specific groups of FABPs. Hydrophilicity, flexibility and accessibility analyses revealed several major putative epitopes for the E. granulosus FABP, EgDf1, that appear to be centred in loops of the EgDf1 3-dimensional structure modelled by molecular replacement.

Presence of a conserved domain of GATA transcription factors in Echinococcus granulosus.

In order to characterize GATA transcription factors in Echinococcus granulosus, a PCR-based cloning strategy was developed. Degenerate oligonucleotides were designed for the most conserved sequence in GATA proteins that include 20 amino acids of the zinc domain. A 60 bp fragment was isolated that had high homology among this sequence and those reported in other species. An analogous sequence was obtained by performing the same procedure with DNA from the free living platyhelminth Dugesia tigrina. High stringency Southern blotting experiments confirmed the presence of this sequence in the parasite genome.

The homeobox-containing gene EgHbx3 from Echinococcus granulosus is expressed in the stalk of protoscoleces.

The homeobox-containing gene EgHbx3 from Echinococcus granulosus is expressed in the stalk of protoscoleces. The expression of the homeobox-containing gene EgHbx3 from E. granulosus was studied in protoscoleces by in situ hybridisation techniques. A method for performing in situ hybridisations on whole mounted hydatic material is described. Our results show a clear positive signal at the protoscolex stalk, when using the antisense EgHbx3 probe. This signal is particularly strong in the proximal end of the stalk (with respect to the protoscolex).

Long-term sequelae of hearing impairment in congenital hypothyroidism.

Hearing loss and its functional consequences were evaluated retrospectively in children with congenital hypothyroidism. From a cohort of 101 children followed longitudinally to evaluate newborn screening, 75 with previous hearing tests were studied. Fifteen (20%) were found to have hearing problems. Of these, nine had unilateral or sensorineural loss mostly at high frequencies, five had a conductive loss, and one had both problems. Hearing impaired children differed from children with normal hearing in age of treatment onset (22 vs 14 days) but not disease severity or duration. A comparison of language and auditory processing skills at ages 3, 5, and 7 years revealed that early speech was delayed in hearing impaired children, whereas deficits persisted in later receptive language and auditory discrimination skills. Comparing hearing impaired children and children with normal hearing with matched control subjects at grade 3 showed that hearing impaired children were poorer readers because of less adequate phonologic processing skills.

Characterization of a flatworm ribosomal RNA-encoding gene: promoter sequence and small subunit rRNA secondary structure.

The transcription start point (tsp) of a ribosomal RNA (rRNA)-encoding gene (rDNA) from Echinococcus granulosus has been mapped at a position located 1.1 kb upstream from the small subunit (SSU) rRNA coding sequence. As expected from the analysis of the putative promoter sequence (-200 to +50), no homology was found with rDNA promoters from other organisms. Nevertheless, some interesting motifs were found. There is a d(T)11 track flanked by an inverted repeat (IR) centered at position -32, which is analogous to the position of the TATA box in promoters transcribed by RNA polymerase II. Two other IR were observed that are also present in the Trypanosoma cruzi rDNA promoter. We have also determined the SSU rDNA sequence and established a secondary structure model. The analysis of the secondary structure strongly suggests that this gene encodes a functional SSU rRNA. The fact that both the promoter and the rRNA coding sequence are derived from the same rDNA repeat indicates that the promoter is also functional.

Long-term effects of L-thyroxine therapy for congenital hypothyroidism.

OBJECTIVE: To study the effects of initial and concurrent dose levels of L-thyroxine on ability and behavior in children with congenital hypothyroidism. METHODS: An existing database, involving a large cohort of children with congenital hypothyroidism detected by neonatal screening, was analyzed retrospectively. There were 94 children: 89 were assessed at age 7 years for intelligence and selective cognitive abilities, and 87 at age 8 years for behavior, achievement, and selective abilities. RESULTS: Subjects were stratified by median split into low and high starting dose groups. The high-dose group performed better on indexes of intelligence, verbal ability, and memory but had more behavior problems reflecting increased anxiety, social withdrawal, and poorer concentration. The dose of L-thyroxine at age 8 years was negatively correlated with memory task performance. CONCLUSION: A higher starting dose of L-thyroxine is beneficial for subsequent intellectual outcome in children with congenital hypothyroidism but may be associated with internalizing behavior problems.

Molecular cloning and characterization of actin genes from Echinococcus granulosus.

An Echinococcus granulosus genomic library has been screened with a mouse beta-actin cDNA probe. Two clones carrying DNA fragments of about 15 kb, possibly derived from the same genome region, have been isolated. This 15-kb genomic region includes 2 actin-related sequences (EgactI and EgactII) separated by about 4 kb. The nucleotide sequences of both genes were determined. The EgactI sequence presents no introns, but an intron of 591 bp was observed in the EgactII sequence. The genes potentially encode 375 and 376 amino-acid-long actins, respectively, with a homology of 85.3%. The deduced amino acid sequences from both genes were compared to the actin sequences from other organisms, showing similarities ranging from 63.5% to 90.6%. The nucleotide sequence of a partial actin cDNA clone has been determined. The deduced amino acids sequence showed a homology of 90.3% and 88.0% in relation to the EgactI and EgactII sequences respectively, suggesting the existence of at least one more actin gene in E. granulosus. This hypothesis is reinforced by the number of bands detected in the Southern blot analysis. Experiments based on the amplification of DNA segments using 3'-specific actin primers indicate that the EgactI gene is transcribed in protoscoleces.