Essential role for PDGF signaling in ophthalmic trigeminal placode induction

Much of the peripheral nervous system of the head is derived from ectodermal thickenings, called placodes, that delaminate or invaginate to form cranial ganglia and sense organs. The trigeminal ganglion, which arises lateral to the midbrain, forms via interactions between the neural tube and adjacent ectoderm. This induction triggers expression of Pax3, ingression of placode cells and their differentiation into neurons. However, the molecular nature of the underlying signals remains unknown. Here, we investigate the role of PDGF signaling in ophthalmic trigeminal placode induction. By in situ hybridization, PDGF receptor β is expressed in the cranial ectoderm at the time of trigeminal placode formation, with the ligand PDGFD expressed in the midbrain neural folds. Blocking PDGF signaling in vitro results in a dose-dependent abrogation of Pax3 expression in recombinants of quail ectoderm with chick neural tube that recapitulate placode induction. In ovo microinjection of PDGF inhibitor causes a similar loss of Pax3 as well as the later placodal marker, CD151, and failure of neuronal differentiation. Conversely, microinjection of exogenous PDGFD increases the number of Pax3+ cells in the trigeminal placode and neurons in the condensing ganglia. Our results provide the first evidence for a signaling pathway involved in ophthalmic (opV) trigeminal placode induction

Fundamental Needs of the Preschool Child

The greatest gift life can yield is its own propagation. The greatest loss one can sustain is the deprivation of that life. These two facts have prompted me to make the present study . I have lost my -precious possession - a beautiful little girl. My loss has convinced me that nothing should be left undone in the promotion of the welfare of the child. A better understanding of the preschool child will enable us to guide him so that he may attain the greatest good at all times. To discover the basic needs of the child is, therefore, the aim of this work

Molecular and tissue interactions governing induction of cranial ectodermal placodes

Whereas neural crest cells are the source of the peripheral nervous system in the trunk of vertebrates, the “ectodermal placodes,” together with neural crest, form the peripheral nervous system of the head. Cranial ectodermal placodes are thickenings in the ectoderm that subsequently ingress or invaginate to make important contributions to cranial ganglia, including epibranchial and trigeminal ganglia, and sensory structures, the ear, nose, lens, and adenohypophysis. Recent studies have uncovered a number of molecular signals mediating induction and differentiation of placodal cells. Here, we described recent advances in understanding the tissue interactions and signals underlying induction and neurogenesis of placodes, with emphasis on the trigeminal and epibranchial. Important roles of Fibroblast Growth Factors, Platelet Derived Growth Factors, Sonic Hedgehog, TGFβ superfamily members, and Wnts are discussed

Evaluation of a rotating swim bench as a surrogate for freestyle swimming

Introduction: The swim bench is an isokinetic ergometer designed for competitive swimming training and is used in research as an accessible alternative to in-water data collection. However, limited literature addresses the biomechanical fidelity of the swim bench relative to in-water swimming. The lack of body roll on a conventional fixed swim bench may limit realistic simulation of the freestyle stroke pull. Accordingly, the KayakPro SwimFast swim bench includes a rotating bench setting; yet specific changes to a competitive swimmer’s kinematics and muscle activity on a rotating bench compared to a fixed bench or in-water swimming are unknown. The purpose of this study was to assess the effect of swim bench setting on freestyle stroke 3D kinematics and muscle activity and evaluate the similarities between the swim bench and pre-existing in-water kinematic data [1]. The rotating bench setting was expected to produce greater shoulder angles and shoulder roll, narrower elbow angles, and less torso flexion than the fixed. Further, the rotating bench setting was expected to generate greater muscle activation of the shoulder prime movers, rotator cuff and scapular stabilizers. In comparison to the in-water data, the stroke length, elbow flexion, total shoulder roll, and length of entry phase were expected to differ on the swim bench.Methods: Fifteen, male, right-handed, collegiate and national level competitive swimmers [20.4±1.18 yrs., 1.81±5.11 m, 78.5±6.01 kg] recruited from local varsity swim teams participated. Upper limb and torso kinematics were collected bilaterally, and surface electromyography (sEMG) collected on 12, right, upper limb muscles. Participants performed 8 sets (4 rotating &amp; 4 fixed) of 30 seconds freestyle stroke pulling on a KayakPro SwimFast swim bench (KayakPro USA LLC, Florida, USA) at 55 stroke cycles/minute.Kinematic data was filtered with a low-pass Butterworth filter at a 4 Hz cut off, and time normalized to percent stroke cycle (%SC). sEMG data was filtered with a band-pass Butterworth filter between 30 to 500 Hz, amplitude normalized to maximum voluntary isometric contraction and time normalized to %SC. Swim bench setting continuous joint angles and muscle activations were compared using statistical non-parametric mapping, one-tailed, paired t-tests. In-water measures were compared to the swim bench using mixed one-way ANOVAs via JMP 17 software (SAS Institute, North Carolina, USA).Results &amp; Discussion: Contrary to the hypotheses, few kinematic and sEMG differences existed between the rotating and fixed swim bench settings. Significant differences were found in the right shoulder elevation (p = 0.021) (Fig. 1), posterior deltoid activation (p = 0.015) (Fig. 2), and infraspinatus activation (p = 0.026). However, the fixed bench produced greater activations and angles rather than the hypothesized rotating setting. Regardless of bench setting, participants laterally flexed the torso, potentially as compensation for the lack of roll allowance on the swim bench overall. The similarities between the settings indicate that the rotating swim bench may not substantially augment the realistic simulation of the underwater freestyle pull. Thus, swimmers can choose the more comfortable setting for training. Compared to in-water swimming, both swim bench settings produced similar elbow flexion ranges; however, the stroke length decreased (p&lt;0.0001), total shoulder roll decreased (p&lt;0.0001), and entry phase duration decreased (p&lt;0.0001) significantly. Despite the difference in shoulder roll magnitude, the movement pattern aligns with current literature, indicating at least partial replication of in-water swimming [2]. The reduction in stroke length may relate to the lack of entry phase on the swim bench because swimmer’s commonly glide further forward during entry and elevate the shoulder to facilitate a longer moment arm for the catch [3]. The reduction in stroke length, total shoulder roll, and entry phase duration with the addition of the lateral torso flexion are notable considerations for long term use. Swimmers could develop associated habits that reduce swimming economy and increase drag when translated to in-water training. Significance: This study provides novel findings for coaches and researchers to consider for the use of the swim bench for training and research purposes.<br/

A Comparative Test of Creative Thinking in Dolphins (Tursiops Truncaus) and Preschool Children

Few studies have investigated the development of creativity as a measure of intelligence/cognitive ability in non-human species and children. A non-verbal method to test creative thinking in bottlenose dolphins and preschoolers was developed and implemented. A comparative investigation of innovation in these species indicates that this creativity measure my demonstrate similarities related to cognitive abilities in the future

Birth of ophthalmic trigeminal neurons initiates early in the placodal ectoderm

The largest of the cranial ganglia, the trigeminal ganglion, relays cutaneous sensations of the head to the central nervous system. Its sensory neurons have a dual origin from both ectodermal placodes and neural crest. Here, we show that the birth of neurons derived from the chick ophthalmic trigeminal placode begins prior to their ingression (HH11), as early as HH8, and considerably earlier than previously suspected (HH16). Furthermore, cells exiting the cell cycle shortly thereafter express the ophthalmic trigeminal placode marker Pax3 (HH9). At HH11, these postmitotic Pax3+ placode cells begin to express the pan-neuronal marker neurofilament while still in the ectoderm. Analysis of the ectodermal origin and distribution of these early postmitotic neurons reveals that the ophthalmic placode extends further rostrally than anticipated, contributing to neurons that reside in and make a significant contribution to the ophthalmic trigeminal nerve. These data redefine the timing and extent of neuron formation from the ophthalmic trigeminal placode

Quantifying the resolution of spatial and temporal representation in children with 22q11.2 deletion syndrome.

ObjectivesOur ability to generate mental representation of magnitude from sensory information affects how we perceive and experience the world. Reduced resolution of the mental representations formed from sensory inputs may generate impairment in the proximal and distal information processes that utilize these representations. Impairment of spatial and temporal information processing likely underpins the non-verbal cognitive impairments observed in 22q11.2 deletion syndrome (22q11DS). The present study builds on prior research by seeking to quantify the resolution of spatial and temporal representation in children with 22q11DS, sex chromosome aneuploidy (SCA), and a typically developing (TD) control group.Participants and methodsChildren (22q11DS = 70, SCA = 49, TD = 46) responded to visual or auditory stimuli with varying difference ratios. The participant's task was to identify which of two sequentially presented stimuli was of larger magnitude in terms of, size, duration, or auditory frequency. Detection threshold was calculated as the minimum difference ratio between the "standard" and the "target" stimuli required to achieve 75% accuracy in detecting that the two stimuli were different.ResultsChildren with 22q11DS required larger magnitude difference between spatial stimuli for accurate identification compared with both the SCA and TD groups (% difference from standard: 22q11DS = 14; SCA = 8; TD: 7; F  = 8.42, p &lt; 0.001). Temporal detection threshold was also higher for the 22q11DS group to both visual (% difference from standard: 22q11DS = 14; SCA = 8; TD = 7; F  = 8.33, p &lt; 0.001) and auditory (% difference from standard: 22q11DS = 23; SCA = 12; TD: 8; F  = 8.99, p &lt; 0.001) stimuli compared with both the SCA and TD groups, while the SCA and TD groups displayed equivalent performance on these measures (p's &gt; 0.05). Pitch detection threshold did not differ among the groups (p's &gt; 0.05).ConclusionsThe observation of higher detection thresholds to spatial and temporal stimuli indicates further evidence for reduced resolution in both spatial and temporal magnitude representation in 22q11DS, that does not extend to frequency magnitude representation (pitch detection), and which is not explained by generalized cognitive impairment alone. These findings generate further support for the hypothesis that spatiotemporal hypergranularity of mental representations contributes to the non-verbal cognitive impairment seen in 22q11DS

Emerging Role of Large-bore Percutaneous Axillary Vascular Access: a Step-by-step Guide

Advances in transcatheter structural heart interventions and temporary mechanical circulatory support have led to increased demand for alternative sites for large-bore vascular access. Percutaneous axillary artery access is an appealing alternative to femoral access in patients with peripheral arterial disease, obesity or for prolonged haemodynamic support where patient mobilisation may be valuable. In particular, axillary access for mechanical circulatory support allows for increased mobility while using the device, facilitating physical therapy and reducing morbidity associated with prolonged bed rest. This article outlines the basic approach to percutaneous axillary vascular access, including patient selection and procedure planning, anatomic axillary artery landmarks, access techniques, sheath removal and management of complications