The effect of changing intraocular pressure on the corneal and scleral curvatures in the fresh porcine eye.

Aim: To measure corneal and scleral radii of curvature in response to intraocular pressure (IOP).

Methods: Using digital photographic profile images of 16 fresh porcine eyes, the curvatures of the cornea and sclera were determined in response to five consecutive incremental 100 mul saline intravitreal injections. IOP was measured and ocular rigidity calculated.

Parent-of-origin effects in attention-deficit hyperactivity disorder.

The goal of the present study was to investigate parent-of-origin effects in attention-deficit hyperactivity disorder (ADHD). Parent-of-origin effects in ADHD may be due to differences in the relative quantity of risk factors transmitted by each parent. Alternatively, parent-of-origin effects may be produced by qualitative differences in the risks transmitted, such as those carried on the sex chromosomes or regulated by genomic imprinting.

The relationship between accommodative amplitude and the ratio of central lens thickness to its equatorial diameter in vertebrate eyes.

Aim: To determine the relationship between accommodative amplitude and central lens thickness/equatorial lens diameter (CLT/ELD) ratio in vertebrates.

Methods: Midsagittal sections of lenses from fixed, post mortem eyes from 125 different vertebrate species were photographed. Their CLT/ELD ratios were correlated with independently published measurements of their accommodative amplitudes.

Viscoelastic shear properties of the fresh porcine lens.

Aim: To determine the viscoelastic properties of the porcine lens

Methods: Linear viscoelastic shear properties of the stroma of four porcine lenses were measured within 5 hours post-mortem, using sinusoidal oscillatory shear deformation. The elastic shear modulus, viscous shear modulus, dynamic viscosity, damping ratio, and phase shift of the lenses were quantified by a controlled-strain, linear simple-shear rheometer at frequencies of 10-50 Hz.

Results: The mean viscoelastic properties and their standard deviations across the frequencies examined were: the elastic shear modulus, G' = 6.

Association of the glutamate receptor subunit gene GRIN2B with attention-deficit/hyperactivity disorder.

The glutamatergic signaling pathway represents an ideal candidate susceptibility system for attention-deficit/hyperactivity disorder (ADHD). Disruption of specific N-methyl-D-aspartate-type glutamate receptor subunit genes (GRIN1, 2A-D) in mice leads to significant alterations in cognitive and/or locomotor behavior including impairments in latent learning, spatial memory tasks and hyperactivity. Here, we tested for association of GRIN2B variants with ADHD, by genotyping nine single nucleotide polymorphisms (SNPs) in 205 nuclear families identified through probands with ADHD.

Sensitivity study of human crystalline lens accommodation.

A nonlinear axisymmetric finite element method (FEM) analysis was employed to determine the critical geometric and material properties that affect human accommodation. In this model, commencing at zero, zonular traction on all lens profiles resulted in central lenticular surface steepening and peripheral surface flattening, with a simultaneous increase in central lens thickness and central optical power. An age-related decline in maximum zonular tension appears to be the most likely etiology for the decrease in accommodative amplitude with age.

Performance monitoring and response inhibition in anxiety disorders with and without comorbid ADHD.

Anxiety disorder (ANX) is characterized by heightened arousal, psychosocial and academic difficulties, and comorbidity with other disorders, in particular, attention-deficit/hyperactivity disorder (ADHD). The heightened arousal contributes to cognitive impairment by adversely affecting executive control of cognition. The nature of the effect on executive control is poorly understood.

The parent interview for child symptoms: a situation-specific clinical research interview for attention-deficit hyperactivity and related disorders.

Objective: To describe the properties of a semistructured research interview of parents designed to evaluate attention-deficit hyperactivity disorder (ADHD) and related psychopathology.

Method: We examined interrater reliability in 48 videotaped interviews randomly selected from a large clinic sample. We examined convergence of the Parent Interview for Child Symptoms (PICS) and Conners' Parent Rating Scale (CPRS) scores in 594 clinic-referred cases and 26 control subjects, comparing the groups generated by cross-tabulation on measures of intelligence, academic achievement, and inhibitory control.

The serotonin receptor HTR1B: gene polymorphisms in attention deficit hyperactivity disorder.

Serotonin plays an essential role in cognition, locomotor activity, and the regulation of sleep, pain, mood, and aggression. Polymorphisms of the HTR1B gene have been implicated in a variety of psychiatric disorders including attention deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). The objectives of this study were to: (i) expand our original investigation of the relationship between the HTR1B receptor gene and attention deficit/hyperactivity and; (ii) to investigate a possible association of obsessive behaviors/perfectionism and the HTR1B gene in a sample of 203 families with an ADHD proband.

Gene for the serotonin transporter and ADHD: no association with two functional polymorphisms.

Evidence from both human and animal studies implicates the serotonergic system in the development of attention-deficit hyperactivity disorder (ADHD) including positive association studies for several key serotonergic genes. The serotonin transporter (HTT) regulates the availability of serotonin by reuptake of the neurotransmitter from the synaptic cleft. Several studies have reported an association of this gene to ADHD, specifically the long variant of a common insertion/deletion polymorphism located in the promoter of this gene that results in increased transcription and higher HTT expression.

Insights into the age-related decline in the amplitude of accommodation of the human lens using a non-linear finite-element model.

Aim: To understand the effect of the geometric and material properties of the lens on the age-related decline in accommodative amplitude.

Methods: Using a non-linear finite-element model, a parametric assessment was carried out to determine the effect of stiffness of the cortex, nucleus, capsule and zonules, and that of thickness of the capsule and lens, on the change in central optical power (COP) associated with zonular traction. Convergence was required for all solutions.

Topographical changes of biconvex objects during equatorial traction: an analogy for accommodation of the human lens.

Aim: To assess and compare the changes in shape of encapsulated biconvex structures undergoing equatorial traction with those changes reported in the human lens during accommodation.

Methods: Equatorial traction was applied to several different biconvex structures: air, water, and gel filled mylar and rubber balloons and spherical vesicles. In the vesicles, traction was applied externally, using optical tweezers, or from within, by the assembly of encapsulated microtubules.

Impairment and recovery in inhibitory control after traumatic brain injury in children: effect of age at injury, injury severity and lesion location.

We examined the effect of traumatic brain injury (TBI) on inhibitory control, trajectories of recovery of inhibitory control, and the effect of age at injury, severity, and lesion location on recovery. Participants were 127 children with TBI aged 5-16 years and 117 controls of similar age. Latency of response inhibition was measured with the stop signal task within 1 month of the injury and again at 3, 6, 12, and 24 months.

Stimulant treatment over 5 years: effects on growth.

Objective: Long-term effects of psychostimulants on growth in height and in weight are investigated in children with attention-deficit/hyperactivity disorder.

Method: Participants were 79 children, 6 to 12 years of age, with attention-deficit/hyperactivity disorder, who were followed annually for up to 5 years, between the years 1993 and 1994 and 1998 and 1999. Annual height and weight measurements were standardized by age and gender using the 2000 Centers for Disease Control and Prevention Growth Charts for the United States and reported as z scores.

Predictors of personality change due to traumatic brain injury in children and adolescents six to twenty-four months after injury.

Phenomenology and predictive factors of personality change due to traumatic brain injury (TBI) 6 to 24 months after injury was investigated in children, ages 5 to 14 years, enrolled from consecutive admissions and followed prospectively for 2 years. Injury and preinjury psychosocial variables were assessed. Personality change occurred in 13% of participants between 6 and 12 months after injury and 12% in the second year after injury.