Multimodal Magnetic Resonance Imaging Study of Treatment-Na?ve Adults with Attention-Deficit/Hyperactivity Disorder

Background

Attention-Deficit/Hiperactivity Disorder (ADHD) is a prevalent disorder, but its neuroanatomical circuitry is still relatively understudied, especially in the adult population. The few morphometric magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) studies available to date have found heterogeneous results. This may be at least partly attributable to some well-known technical limitations of the conventional voxel-based methods usually employed to analyze such neuroimaging data. Moreover, there is a great paucity of imaging studies of adult ADHD to date that have excluded patients with history of use of stimulant medication.

Methods

A newly validated method named optimally-discriminative voxel-based analysis (ODVBA) was applied to multimodal (structural and DTI) MRI data acquired from 22 treatment-naïve ADHD adults and 19 age- and gender-matched healthy controls (HC).

Results

Regarding DTI data, we found higher fractional anisotropy in ADHD relative to HC encompassing the white matter (WM) of the bilateral superior frontal gyrus, right middle frontal left gyrus, left postcentral gyrus, bilateral cingulate gyrus, bilateral middle temporal gyrus and right superior temporal gyrus; reductions in trace (a measure of diffusivity) in ADHD relative to HC were also found in fronto-striatal-parieto-occipital circuits, including the right superior frontal gyrus and bilateral middle frontal gyrus, right precentral gyrus, left middle occipital gyrus and bilateral cingulate gyrus, as well as the left body and right splenium of the corpus callosum, right superior corona radiata, and right superior longitudinal and fronto-occipital fasciculi. Volumetric abnormalities in ADHD subjects were found only at a trend level of significance, including reduced gray matter (GM) in the right angular gyrus, and increased GM in the right supplementary motor area and superior frontal gyrus.

Conclusions

Our results suggest that adult ADHD is associated with neuroanatomical abnormalities mainly affecting the WM microstructure in fronto-parieto-temporal circuits that have been implicated in cognitive, emotional and visuomotor processes.     

Recombinant Escherichia coli heat-labile enterotoxin B subunit humoral adjuvant effect depends on dose and administration route

Information on the use of Escherichia coli heat-labile enterotoxin B subunit (LTB) as a parenteral adjuvant is scarce. We evaluate the adjuvant effect of different concentrations of recombinant LTB (rLTB), as well as the influence of administration route (intramuscular and subcutaneous) on mice immune response. The use of 10 μg/dose of rLTB as adjuvant of an inactivated vaccine composed by Suid herpesvirus type 1 (SuHV-1), used to immunize mice intramuscularly, induced the highest average titers of anti-SuHV-1 antibodies (P < 0.05). The same vaccines used subcutaneously induced lower titers of antibodies. The lower the anti-rLTB humoral response determined by ELISA, the higher was its adjuvant activity. In the challenge experiment with SuHV-1, 56% (14/25) (P < 0.05) of the animals inoculated intramuscularly and 32% (8/25) inoculated subcutaneously survived, highlighting the influence of the concentration and the route of administration of rLTB on its performance as an adjuvant. Therefore, rLTB can significantly help in the induction of immunity against SuHV-1 in mice, especially if used intramuscularly in the concentration of 10 μg/dose, representing the best cost-benefit ratio.     

Preparation of soybean seed samples for FT-IR microspectroscopy

Typical preparation of seed samples for infrared (IR) microspectroscopy involves imbibition of the seed for varying time periods followed by cryosectioning. Imbibition, however, may initiate germination even at 4° C with associated changes in the chemistry of the sample. We have found that it is possible to section seeds that are sufficiently hard, such as soybeans, on a standard laboratory microtome without imbibition. The use of dry sectioning of unimbibed seeds is reported here, as well as a comparison of different mounting media and modes of analysis. Glycerol, Tissue-Tek, and ethanol were used as mounting media, and the quality of the resulting spectra was assessed. Ethanol was the preferred mountant, because it dried quickly with no residue and thus did not interfere with the spectrum of interest. Analysis in transmission mode using barium fluoride windows to hold the samples was compared with transmission-reflection analysis with sections mounted on special infrared-reflecting slides. The two modes of analysis performed well in different regions of the spectrum. The mode of analysis (transmission vs. transmission-reflection) should be based on the components of greatest interest in the sample.     

Unbalanced resting-state networks activity in psychophysiological insomnia

Sleep and Biological Rhythms - Psychophysiological insomnia (PI) is a clinical condition characterized by sleep-related disturbing cognitive activity and biased self-related information processing....     

Secreted gelsolin inhibits DNGR-1-dependent cross-presentation and cancer immunity

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Combined use of ELISA and Western blot with recombinant N protein is a powerful tool for the immunodiagnosis of avian infectious bronchitis

Background

The avian infectious bronchitis virus (IBV) remains a significant source of loss in the poultry industry and early diagnosis is required to prevent the disease from spreading. This study examined the combined use of an ELISA and Western blot (WB) to detect antibodies against the nucleocapsid protein (N) of IBV. The coding sequence for N was amplified by RT-PCR and expressed in Escherichia coli. A soluble recombinant N protein (rN) of approximately 50?kDa was obtained. A total of 389 sera were tested against the rN in ELISA and the results were compared with those of the commercial IDEXX IBV Ab test. ELISA-rN achieved a 90.34% sensitivity and 90.16% specificity. WB confirmed all false negative sera in ELISA-rN or IDEXX test as truly positive. The current study indicate that the combined use of rN in ELISA and WB is a powerful tool for the immunodiagnosis of avian infectious bronchitis.

Methods

Constructed recombinant pAE/n expression vectors were used to transform E. coli BL21(DE3) Star competent cells (Invitrogen). The rN of infectious bronchitis virus was purified by affinity chromatography using HisTrap HP 1?mL columns pre-packed with pre-charged Ni Sepharose in the ÄKTAprime Automated Liquid Chromatography system (GE Healthcare). A total of 389 serum samples from chickens were used to develop and evaluate the ELISA-rN test. To standardize the indirect ELISA development, serum dilutions (1:100, 1:200 and 1:400) and different concentrations of purified rN antigen (50, 100 and 200?ng/well) were tested. Positive and negative sera for IBV were used as controls. The results were compared with those obtained from a commercial kit. Serum samples scored as negative with the commercial kit but as positive with the ELISA-rN were further analysed by Western blot analyses using the rN protein as an antigen. The results of the ELISA-rN were compared to the commercial kit results using receiver-operating characteristics curves, area under the curve, and confidence intervals with the software GraphPad Prism version 6.0 for Windows (GraphPad Software, USA).

Results

The expected cDNA fragment of approximately 1240?bp was successfully amplified by PCR using primers designed to select for the coding region of the N protein. The rN was expressed as a soluble protein to avoid the refolding steps and, after purification a yield of 10?mg/L of rN was obtained. The SDS-PAGE results demonstrated the presence of two distinct bands that had a molecular mass of approximately 45 and 50 KDa. Out of 244 sera that scored positive in the commercial ELISA IDEXX IBV Ab Test, 220 were also positive in the ELISA-rN, yielding an ELISA-rN test sensitivity of 90.16%. Out of 145 sera that scored negative in the IDEXX IBV Ab Test, 131 also scored negative in the ELISA-rN, indicating a specificity of 90.34%. Sera that tested negative in the ELISA-rN and positive in the commercial test also reacted with the rN protein in Western blot.

Conclusions

The association between the ELISA and Western blot techniques developed in this study with a subunit of IBV (rN) were able to detect antibodies that the commercial ELISA did not detect suggesting that the ELISA-rN has greater sensitivity.

     

The RIG‐I‐like receptor LGP2 inhibits Dicer‐dependent processing of long double‐stranded RNA and blocks RNA interference in mammalian cells

In vertebrates, the presence of viral RNA in the cytosol is sensed by members of the RIG‐I‐like receptor (RLR) family, which signal to induce production of type I interferons (IFN). These key antiviral cytokines act in a paracrine and autocrine manner to induce hundreds of interferon‐stimulated genes (ISGs), whose protein products restrict viral entry, replication and budding. ISGs include the RLRs themselves: RIG‐I, MDA5 and, the least‐studied family member, LGP2. In contrast, the IFN system is absent in plants and invertebrates, which defend themselves from viral intruders using RNA interference (RNAi). In RNAi, the endoribonuclease Dicer cleaves virus‐derived double‐stranded RNA (dsRNA) into small interfering RNAs (siRNAs) that target complementary viral RNA for cleavage. Interestingly, the RNAi machinery is conserved in mammals, and we have recently demonstrated that it is able to participate in mammalian antiviral defence in conditions in which the IFN system is suppressed. In contrast, when the IFN system is active, one or more ISGs act to mask or suppress antiviral RNAi. Here, we demonstrate that LGP2 constitutes one of the ISGs that can inhibit antiviral RNAi in mammals. We show that LGP2 associates with Dicer and inhibits cleavage of dsRNA into siRNAs both in vitro and in cells. Further, we show that in differentiated cells lacking components of the IFN response, ectopic expression of LGP2 interferes with RNAi‐dependent suppression of gene expression. Conversely, genetic loss of LGP2 uncovers dsRNA‐mediated RNAi albeit less strongly than complete loss of the IFN system. Thus, the inefficiency of RNAi as a mechanism of antiviral defence in mammalian somatic cells can be in part attributed to Dicer inhibition by LGP2 induced by type I IFNs. LGP2‐mediated antagonism of dsRNA‐mediated RNAi may help ensure that viral dsRNA substrates are preserved in order to serve as targets of antiviral ISG proteins.     

Role of microorganisms in mineralization processes in intertidal surface sediments subject to high temperatures: An incubation experiment

In order to study how N, P, Fe, Mn and S concentrations in pore waters change with time at different temperatures, an incubation experiment was carried out with surficial intertidal sediment. To evaluate the importance of benthic microorganisms, an abiotic control was established by poisoning sediment. The live and poisoned sediments were incubated for ten hours at 10, 21, 30 and 40°C. Dissolved Inorganic Nitrogen (DIN), Dissolved Reactive Phosphorus (DRP), NH₄ ⁺, total dissolved manganese (Mn_diss), total dissolved iron (Fe_diss) and soluble inorganic sulphide (HS^–)_t were followed in the pore water samples. Results indicated that high temperature influenced nitrification, allowing accumulation of ammonia and that microorganism activity did not seem important for Mn reduction. Anaerobic nitrification by Mn reduction was advanced as an explanation of the behaviour of DIN during the experiment.     

Grapevine petioles are more sensitive to drought induced embolism than stems: evidence from in vivo MRI and microcomputed tomography observations of hydraulic vulnerability segmentation

The ‘hydraulic vulnerability segmentation’ hypothesis predicts that expendable distal organs are more susceptible to water stress‐induced embolism than the main stem of the plant. In the current work, we present the first in vivo visualization of this phenomenon. In two separate experiments, using magnetic resonance imaging or synchrotron‐based microcomputed tomography, grapevines (Vitis vinifera) were dehydrated while simultaneously scanning the main stems and petioles for the occurrence of emboli at different xylem pressures (Ψ_x). Magnetic resonance imaging revealed that 50% of the conductive xylem area of the petioles was embolized at a Ψ_x of ?1.54 MPa, whereas the stems did not reach similar losses until ?1.9 MPa. Microcomputed tomography confirmed these findings, showing that approximately half the vessels in the petioles were embolized at a Ψ_x of ?1.6 MPa, whereas only few were embolized in the stems. Petioles were shown to be more resistant to water stress‐induced embolism than previously measured with invasive hydraulic methods. The results provide the first direct evidence for the hydraulic vulnerability segmentation hypothesis and highlight its importance in grapevine responses to severe water stress. Additionally, these data suggest that air entry through the petiole into the stem is unlikely in grapevines during drought.