Artifacts due to stimulus correlated motion in functional imaging of the brain

To assess the effect of stimulus correlated motion on the appearance of functional magnetic resonance images, conventional visual and motor protocols were each performed by four normal volunteers and an image co-registration technique was used to retrospectively monitor subject motion. In three studies synthetic data sets were constructed from single baseline images using the positional information obtained from the co-registration procedure. Cumulative difference images were then created from both the synthetic and functional image sets. Stimulus correlated motion was detected in all eight studies and the synthetic cumulative difference images showed striking similarities to the equivalent functional images in each case.     

The origins of life -- the 'protein interaction world' hypothesis: protein interactions were the first form of self-reproducing life and nucleic acids evolved later as memory molecules

The 'protein interaction world' (PIW) hypothesis of the origins of life assumes that life emerged as a self-reproducing and expanding system of protein interactions. In mainstream molecular biology, 'replication' refers to the material copying of molecules such as nucleic acids. However, PIW is conceptualized as an abstract communication system constituted by the interactions between proteins, in which 'replication' happens at the level of self-reproduction of these interactions between proteins. Densely concentrated peptide interaction systems may have reproduced and expanded as 'protocell' vesicles surrounded by lipid bi-layer membranes. Protocells led to the emergence of proto-RNA molecules of greater chemical stability which served as chemically differentiated 'memories' of peptide interaction states, thereby facilitating the reproduction and expansion of protocells. Simplification-driven expansion led to the selection of biotic amino acids and the reduction of the typical RNA alphabet to the four usual bases (A, C, G and U). Dense interactions between RNA molecules led to the emergence of the RNA interaction subsystem of the cell, and to the emergence of 'memories' of RNA interactions in the form of DNA molecules with greater chemical stability. The expansion of DNA molecule interactions led to the dense clustering and encapsulation of DNA molecules within the cell nucleus. RNA molecules therefore serve as memories of protein interactions and DNA molecules are memories of RNA interactions. We believe that the PIW hypothesis is more evolutionarily plausible than the mainstream RNA world hypothesis, and has greater explanatory power.     

Association analysis of 5-HTTLPR variants, 5-HT2a receptor gene 102T/C polymorphism and migraine

It is well known that migraine has a strong genetic component, although the type and number of genes involved is not yet clear. There is evidence to suggest that serotonin-related genes participate in the pathogenesis of migraine. Previous studies have shown that gender differences influence the serotonergic neurotransmission and, in addition, the migraine prevalence is higher in females than males. Therefore, we investigated the functional polymorphism in the upstream regulatory region of the serotonin transporter gene (5-HTTLPR) and the 102T/C polymorphism of the 5-HT2A receptor gene in the Hungarian female population. These genes were analysed in 126 migraine sufferers (with or without aura)and 101 unrelated healthy controls using case control design. A borderline association (chi2 = 3.84, df = 1, p = 0.049; OR = 1.45, 95% CI = 1.00-2.12) between 5-HTTLPR short (S) allele and migraine was found. No significant difference between migraine sufferers and controls was observed for the 102T/C polymorphism of 5-HT2A receptor gene. Furthermore, there was no significant interaction between5-HTTLPR and 102T/C polymorphisms in our study population. In conclusion, our results support that the genetic susceptibility of migraine may be associated with a locus at or near the 5-HT transporter gene.     

Haptic selective attention by foot and by hand

Nonvisual perceptions of a wielded object's spatial properties are based on the quantities expressing the object's mass distribution, quantities that are invariant during the wielding. The mechanoreceptors underlying the kind of haptic perception involved in wielding – referred to as effortful, kinesthetic, or dynamic touch – are those embedded in the muscles, tendons, and ligaments. The present experiment's focus was the selectivity of this muscle-based form of haptic perception. For an occluded rod grasped by the hand at some intermediate position along its length, participants can attend to and report selectively the rod's full length, its partial lengths (fore or aft of the hand), and the position of the grip. The present experiment evaluated whether participants could similarly attend selectively when wielding by foot. For a given rod attached to and wielded by foot or attached to (i.e. grasped) and wielded by hand, participants reported (by magnitude production) the rod's whole length or fractional length leftward of the point of attachment. On measures of mean perceived length, accuracy, and reliability, the degree of differentiation of partial from full extent achieved by means of the foot matched that achieved by means of the hand. Despite their neural, anatomical, and experiential differences, the lower and upper limbs seem to abide by the same principles of selective muscle-based perception and seem to express this perceptual function with equal facility.     

Sucrose sham feeding decreases accumbens norepinephrine in the rat

Noradrenergic projections from the dorsomedial medulla reach the shell of the nucleus accumbens (NAcc), a structure implicated in both reward and feeding behavior. Despite this relationship, the effect of food reward on accumbens norepinephrine (NE) remains uninvestigated. In the course of assessing dopamine (DA) in the NAcc during sucrose ingestion [0.03, 0.1, and 0.3 M; Am. J. Physiol., Regul. Integr. Comp. Physiol., 286 (2004) R31], we also analyzed NE in the microdialysis samples from 14 ad-libitum-fed male rats. In contrast to DA, which increased with sucrose concentration (+20-47%) during sham feeding, in the same animals, NE levels were reduced (approximately -20%), regardless of sucrose concentration. These results demonstrate a novel relationship between accumbens DA and NE during orosensory stimulation with a preferred nutrient.     

Effect of vinpocetine on retrograde axoplasmic transport

Vinpocetine, a derivate of vincamine, is widely used in the clinical pharmacotherapy of cerebral circulatory diseases. Herewith we report on a novel effect of vinpocetine: inhibition of retrograde axoplasmic transport of nerve growth factor (NGF) in the peripheral nerve. Blockade of retrograde transport of NGF results in transganglionic degenerative atrophy (TDA) in the segmentally related ipsilateral superficial spinal dorsal horn, which is characterized by depletion of the marker enzymes fluoride-resistant acid phosphatase (FRAP) and thiamine monophosphatase (TMP). At the same time, pain-related neuropeptides such as substance P (SP) and calcitonin gene-related peptide (CGRP), are depleted from lamina I-III from the segmentally related, ipsitateral Rolando substance of the spinal cord. On the basis of these experiments it is suggested that vinpocetine may result in a locally restricted decrease of nociception, that might be useful in clinical treatment of intractable pain. Pilot self-experiments support this assumption.     

Analyzing the learning curves of a novice and an experienced urologist for transrectal magnetic resonance imaging-ultrasound fusion prostate biopsy

BackgroundThe aim of the current study was to evaluate and compare the learning curves of transrectal magnetic resonance imaging-ultrasound fusion biopsy for two urologists with different backgrounds (Operator 1: experienced, self-trained and Operator 2: novice, trained by a mentor/MRI reading courses).MethodsA cohort of 400 patients who underwent fusion prostate biopsy in our department was analyzed. The learning curves were assessed in terms of overall and clinically significant prostate cancer (PCa) detection rates, percentage of positive biopsy cores/targeted and the percentage of PCa tissue on positive targeted cores.ResultsIncreasing trends were observed for both urologists in terms of all biopsy outcomes during the study time. For the novice urologist, a significant increase was observed for overall PCa detection rate, but not for clinically significant disease (25.44%, P=0.04/15%, P=0.145). Operator 1 showed an increasing diagnosis yield of clinically significant disease up to 104 cases. Similar cancer detection rates were observed when comparing the first and last biopsies performed by both operators. Multivariate analysis adjusted for age, PSA, prostate volume, lesion diameter and PIRADS score showed an increase of PCa detection with 51% for every 52 biopsies performed (P=0.022).ConclusionsWhen starting with magnetic resonance imaging-ultrasound fusion prostate biopsy, mentoring and prostate magnetic resonance imaging reading training allow a novice urologist to demonstrate a good initial PCa detection rate. After about 52 cases, he reached a stable PCa and clinically significant PCa detection rate, that was similar to that of an experienced urologist.     

The Caenorhabditis elegans APC-related gene apr-1 is required for epithelial cell migration and Hox gene expression

Inactivation of the Caenorhabditis elegans APC-related gene (apr-1) has pointed at two separate functions of apr-1. First, apr-1 is required for the migration of epithelial cells during morphogenesis of the embryo. In this process, APR-1 may act in a Cadherin/alpha-Catenin/beta-Catenin complex as a component of adherens junctions. Second, apr-1 is required for Hox gene expression, most likely by positively regulating the activity of the Wingless signaling pathway. During embryogenesis, apr-1 is required for the expression of ceh-13 labial in anterior seam and muscle cells and during larval development, apr-1 is necessary for the expression of lin-39 deformed in the vulval precursor cells. Thus, APR-1 may positively regulate the activity of the beta-Catenin/Armadillo-related proteins HMP-2 in migrating epithelial cells and BAR-1 in the vulval precursor cells.     

Studies strive to place fMRI on firm foundation

Research designed to reproduce and extend the scope of fMRI studies found that startling results could be produced, but that there was also a disconcerting variability among subjects. Some patients consistently showed marked changes, others showed little or no effect and a third group displayed quite variable results.