Fibroblast growth factor-hedgehog interdependence during retina regeneration.

The embryonic chick is able to regenerate the retina after it has been removed. We have previously shown that proliferating stem/progenitor cells present in the ciliary body/ciliary marginal zone (CB/CMZ) of the chick eye are responsible for regeneration, which can be induced by ectopic fibroblast growth factor-2 (FGF2) or Sonic hedgehog (Shh). Here, we reveal the mechanisms showing how FGF2 and Shh signaling are interdependent during retina regeneration. If the FGF pathway is inhibited, regeneration stimulated by Shh is inhibited. Likewise, if the Hedgehog pathway is inhibited, regeneration stimulated by FGF2 is inhibited. We examined early signaling events in the CB/CMZ and found that FGF2 or Shh induced a robust Erk phosphorylation during the early stages of retina regeneration. Shh also up-regulated the expression of several members of the FGF signaling pathway. We show that ectopic FGF2 or Shh overexpression increased the number of phosphohistone 3 (PH3)-positive cells in the CB/CMZ and inhibition of either pathway decreased the number of PH3-positive cells. Additionally, both FGF and Hh signaling are required for cell survival in the CB/CMZ, whereas Hh and not FGF signaling plays a role in maintaining the identity of the retinal progenitor population in this region. Combined, our results support a model where the FGF and Hedgehog pathways work together to stimulate retina regeneration.     

Osteometric Dimensions of the Laminas of the Spine

The present study was undertaken to evaluate the dimensions of the laminas from C2 to L5 by using adult human spine specimens for the objective of providing a set of quantitative data for the laminas from C2 to L5 vertebrae.There exists enormous amount of Anatomic data based on facet and pedicle parameters by different research workers, but it seems that the detailed studies based on measurements of laminar parameters from cervical to lumbar spines are almost nil.Forty spines (920 vertebrae) were considered for the present study. Anatomic evaluation of the laminas'included the laminar height, width, thickness, width angle & slope angle.The greatest laminar height was observed at T11 for males & females ( 22.8 ± 2.1 mm, 23.0 + 1.8mm) respectively. There was a marked change in pattern at L5 where there was a decrease in laminar height from that of preceding lumbar levels.The greatest laminar width was at-L5 for males & females (12.1 ± 2.4mm 11.5 ± 2.1 mm ) respectively. The laminar thickness was maximum at T3 for males and females (5:2 ± 0.7mm & 5.1 ± 0.2mm ) respectively. The maximum width angle was at T9 for males (99.2 ± 9.7mm) & at L4for females (100.6 ± 12.3mm). The-slope angle was maximum at L5 for males and females (113.5 ± 4.8mm & 118.0 ± 1.4mm) respectively.Thus, for the proper, understanding of the weight transmission through the spine and it related hypothesis the Anatomic parameters of the laminas provided by the present study are very important and also they provide an adequate database necessary for the surgical placement of sublaminar instruments in spine related surgeries.     

Tactile recalibration of auditory spatial representations

In the well-known spatial ventriloquism effect, auditory stimuli are mislocalized towards the location of synchronous but spatially disparate visual stimuli. Recent studies have demonstrated a similar influence of tactile stimuli on auditory localization, which predominantly operates in an external coordinate system. Here, we investigated whether this audio-tactile ventriloquist illusion leads to comparable aftereffects in the perception of auditory space as have been observed previously for audiovisual stimulation. Participants performed a relative sound localization task in which they had to judge whether a brief sound was perceived at the same or a different location as a preceding tactile stimulus (“Experiment 1”) or to the left or right of a preceding visual stimulus (“Experiment 2”). Sound localization ability was measured before and after exposure to synchronous audio-tactile stimuli with a constant spatial disparity. After audio-tactile adaptation, unimodal sound localization was shifted in the direction of the tactile stimuli during the preceding adaptation phase in both tasks. This finding provides evidence for the existence of an audio-tactile ventriloquism aftereffect and suggests that auditory space (rather than specific audio-tactile connections) can be rapidly recalibrated to compensate for audio-tactile spatial disparities.     

Novel ring chromosome composed of X- and Y-derived material in a girl with manifestations of Ullrich-Turner syndrome

We present a female infant who has a novel genetic variant of Ullrich-Turner syndrome. Chromosome analysis on amniotic fluid cells obtained because of ultrasound observation of nuchal thickening showed 45,X in all cells. The infant was born with a low posterior hairline and moderate edema over hands and feet. Postnatal chromosome analysis demonstrated two cell lines-47% of the metaphases were 45,X, but 53% had a ring chromosome in addition to the normal X. FISH studies using alpha satellite probes, an X-whole-chromosome-paint (WCP) probe, and a Y-cocktail probe determined that the ring was composed of both X and Y sequences. FISH studies also determined that the KAL locus was present on the ring, but that XIST was absent. PCR-based analysis of lymphocyte DNA documented that the ring contained sequences from both the short and the long arm of the Y chromosome. X-chromosome analysis using a panel of highly polymorphic markers indicated that the ring contained material derived only from Xp22.1 to Xp21.3. No Xq material was identified on the ring, and androgen receptor-based X-inactivation studies suggested that the intact X chromosome was not subject to random X inactivation.     

Effects of prenatal cocaine exposure and postnatal environment on child development

Studies on the long-term developmental effects of in utero cocaine exposure are few and the small number of studies published do not consider the postnatal environment. The present investigation was conducted to quantify the role that postnatal environment played compared to prenatal exposure. Four groups of 25 infants, each assessed at 12 months of age, were included in the study design: 1) noncocaine-exposed children residing with their biological parents in low socioeconomic environments, 2) cocaine-exposed children living with their biological parents in low socioeconomic environments, 3) noncocaine-exposed children adopted at birth in middle to upper-middle socioeconomic environments, and 4) cocaine-exposed children adopted at birth. Infants were assessed by the Uzgiris-Hunt Ordinal Scales of Infant Psychological Development, the Fagan Test of Infant Intelligence, and the Infant Monitoring Questionnaire. Height and head circumference were measured. Gender and ethnicity were controlled statistically. Significant differences were found in cognitive functioning, in fine motor development, and in physical growth between control and prenatally cocaine-exposed children. Adoption enhanced cognitive functioning and fine motor skills among infants not exposed to cocaine prenatally, but had no apparent effect on infants prenatally exposed to cocaine. Am. J. Hum. Biol. 12:417–428, 2000. © 2000 Wiley-Liss, Inc.     

Audiotactile interactions in roughness perception

The sounds produced when we touch textured surfaces frequently provide information regarding the structure of those surfaces. It has recently been demonstrated that the perception of the texture of the hands can be modified simply by manipulating the frequency content of such touch-related sounds. We investigated whether similar auditory manipulations change people's perception of the roughness of abrasive surfaces (experiment 1). Participants were required to make speeded, forced-choice discrimination responses regarding the roughness of a series of abrasive samples which they touched briefly. Analysis of discrimination errors verified that tactile roughness perception was modulated by the frequency content of the auditory feedback. Specifically, attenuating high frequencies led to a bias towards an increased perception of tactile smoothness. In experiment 2, we replicated the rubbing-hands manipulation of previous experimenters while participants rated either the perceived roughness or wetness of their hands. The wetness scale data replicated the results in the literature, while the roughness scale data replicated the result from experiment 1. A final experiment showed that delaying the auditory feedback from the hand-rubbing reduced the magnitude of this parchment-skin illusion. These experiments demonstrate the dramatic effect that auditory frequency manipulations can have on the perceived tactile roughness and moistness of surfaces, and are consistent with the proposal that different auditory perceptual dimensions may have varying salience for different surfaces.