Fake hands in action: embodiment and control of supernumerary limbs

Demonstrations that the brain can incorporate a fake limb into our bodily representations when stroked in synchrony with our unseen real hand [(the rubber hand illusion (RHI)] are now commonplace. Such demonstrations highlight the dynamic flexibility of the perceptual body image, but evidence for comparable RHI-sensitive changes in the body schema used for action is less common. Recent evidence from the RHI supports a distinction between bodily representations for perception (body image) and for action (body schema) (Kammers et al. in Neuropsychologia 44:2430–2436, 2006). The current study challenges and extends these findings by demonstrating that active synchronous stroking of a brush not only elicits perceptual embodiment of a fake limb (body image) but also affects subsequent reaching error (body schema). Participants were presented with two moving fake left hands. When only one was synchronous during active touch, ownership was claimed for the synchronous hand only and the accuracy of reaching was consistent with control of the synchronous hand. When both fake hands were synchronous, ownership was claimed over both, but only one was controlled. Thus, it would appear that fake limbs can be incorporated into the body schema as well as the body image, but while multiple limbs can be incorporated into the body image, the body schema can accommodate only one

FIV establishes a latent infection in feline peripheral blood CD4+ T lymphocytes in vivo during the asymptomatic phase of infection

<p>Abstract</p> <p>Background</p> <p>Feline immunodeficiency virus (FIV) is a lentivirus of cats that establishes a lifelong persistent infection with immunologic impairment.</p> <p>Results</p> <p>In an approximately 2 year-long experimental infection study, cats infected with a biological isolate of FIV clade C demonstrated undetectable plasma viral loads from 10 months post-infection onward. Viral DNA was detected in CD4+CD25+ and CD4+CD25- T cells isolated from infected cats whereas viral RNA was not detected at multiple time points during the early chronic phase of infection. Viral transcription could be reactivated in latently infected CD4+ T cells <it>ex vivo </it>as demonstrated by detectable FIV <it>gag </it>RNA and 2-long terminal repeat (LTR) circle junctions. Viral LTR and <it>gag </it>sequences amplified from peripheral blood mononuclear cells during early and chronic stages of infection demonstrated minimal to no viral sequence variation.</p> <p>Conclusions</p> <p>Collectively, these findings are consistent with FIV latency in peripheral blood CD4+ T cells isolated from chronically infected cats. The ability to isolate latently FIV-infected CD4+ T lymphocytes from FIV-infected cats provides a platform for the study of <it>in vivo </it>mechanisms of lentiviral latency.</p

Role of Stem Cells in Human Uterine Leiomyoma Growth

Uterine leiomyoma is the most common benign tumor in reproductive-age women. Each leiomyoma is thought to be a benign monoclonal tumor arising from a single transformed myometrial smooth muscle cell; however, it is not known what leiomyoma cell type is responsible for tumor growth. Thus, we tested the hypothesis that a distinct stem/reservoir cell-enriched population, designated as the leiomyoma-derived side population (LMSP), is responsible for cell proliferation and tumor growth.LMSP comprised approximately 1% of all leiomyoma and 2% of all myometrium-derived cells. All LMSP and leiomyoma-derived main population (LMMP) but none of the side or main population cells isolated from adjacent myometrium carried a mediator complex subunit 12 mutation, a genetic marker of neoplastic transformation. Messenger RNA levels for estrogen receptor-α, progesterone receptor and smooth muscle cell markers were barely detectable and significantly lower in the LMSP compared with the LMMP. LMSP alone did not attach or survive in monolayer culture in the presence or absence of estradiol and progestin, whereas LMMP readily grew under these conditions. LMSP did attach and survive when directly mixed with unsorted myometrial cells in monolayer culture. After resorting and reculturing, LMSP gained full potential of proliferation. Intriguingly, xenografts comprised of LMSP and unsorted myometrial smooth muscle cells grew into relatively large tumors (3.67 ± 1.07 mm(3)), whereas xenografts comprised of LMMP and unsorted myometrial smooth muscle cells produced smaller tumors (0.54 ± 0.20 mm(3), p<0.05, n = 10 paired patient samples). LMSP xenografts displayed significantly higher proliferative activity compared with LMMP xenografts (p<0.05).Our data suggest that LMSP, which have stem/reservoir cell characteristics, are necessary for in vivo growth of leiomyoma xenograft tumors. Lower estrogen and progesterone receptor levels in LMSP suggests an indirect paracrine effect of steroid hormones on stem cells via the mature neighboring cells

Development of a Noise Reduction Filter Algorithm for Pediatric Body Images in Multidetector CT

Recently, several types of post-processing image filter which was designed to reduce noise allowing a corresponding dose reduction in CT images have been proposed and these were reported to be useful for noise reduction of CT images of adult patients. However, these have not been reported on adaptation for pediatric patients. Because they are not very effective with small (<20 cm) display fields of view, they could not be used for pediatric (e.g., premature babies and infants) body CT images. In order to solve this restriction, we have developed a new noise reduction filter algorithm which can be applicable for pediatric body CT images. This algorithm is based on a three-dimensional post processing, in which output pixel values are calculated by multi-directional, one-dimensional median filters on original volumetric datasets. The processed directions were selected except in in-plane (axial plane) direction, and consequently the in-plane spatial resolution was not affected by the filter. Also, in other directions, the spatial resolutions including slice thickness were almost maintained due to a characteristic of non-linear filtering of the median filter. From the results of phantom studies, the proposed algorithm could reduce standard deviation values as a noise index by up to 30% without affecting the spatial resolution of all directions, and therefore, contrast-to-noise ratio was improved by up to 30%. This newly developed filter algorithm will be useful for the diagnosis and radiation dose reduction of pediatric body CT images

Modulation of hormonal signaling in the brain by steroid receptor coactivators.

Nuclear receptors, such as estrogen, glucocorticoid or thyroid hormone receptors, have been shown to play a critical role in brain development and physiology. The activity of these receptors is modulated by the interaction with several proteins and, in particular, coactivators are required to enhance their transcriptional activity. The steroid receptor coactivators (SRC-1, -2 and -3) are currently the best characterized coactivators and we review here the current knowledge on the distribution and function of these proteins in the brain. Knock-out models and antisense techniques have demonstrated the requirement for SRC-1 and -2 in the brain, focusing mainly on steroid and thyroid hormone-dependent development and behavior. The precise function of SRC-3 in the brain is currently unknown but its presence throughout the brain suggests an important function. Although the molecular biology of SRCs is relatively well known, the in vivo control of their expression, post-translational modifications and time- and cell-specific interactions with the different nuclear receptors remain elusive. A complete understanding of hormone action on brain and behavior will not be attained until a better knowledge of coactivator physiology is achieved