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Factors Affecting Contrast Sensitivity in Healthy Individuals: A Pilot Study.

ABSTRACT: To determine the demographic and ocular features affecting contrast sensitivity levels in healthy individuals.Seventy-four eyes of 37 subjects (7-65 years old) with refractive errors less than 1.0 diopter, no history of ocular surgery, and 20/20 visual acuity were included in the study. The participants were divided by age into three groups: group 1, 7-19 years, n=11; group 2, 20-49 years, n=15; and group 3, 50-65 years, n=11. All subjects underwent anterior and posterior segment evaluation, intraocular pressure measurements, refraction measurements, and clinical evaluation for strabismus. Contrast static test was performed using Metrovision MonPack 3 vision monitor system after measuring pupil diameter. Photopic and mesopic measurements were taken sequentially from right eyes, left eyes, and both eyes together.Contrast sensitivity at intermediate and high spatial frequencies was lower with increasing age. Binocular measurements were better than monocular, and mesopic measurements were better than photopic measurements at all spatial frequencies. Contrast sensitivity at higher spatial frequency was lower with hyperopic refraction values.Increasing age, small pupil diameter, hyperopia, and photopic conditions were associated with lower contrast sensitivity in healthy individuals. Binocular contrast sensitivity measurements were better than monocular contrast sensitivity measurements in all conditions and spatial frequencies.

SUBMITTER: Karatepe AS

PROVIDER: S-EPMC5384124 | biostudies-other | 2017 Apr

REPOSITORIES: biostudies-other

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Factors affecting crowded acuity: eccentricity and contrast.

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| S-EPMC3837536 | biostudies-literature

Pilot study of sleep and meal timing effects, independent of sleep duration and food intake, on insulin sensitivity in healthy individuals.

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| S-EPMC5771427 | biostudies-literature

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Pilot Study of the Importance of Factors Affecting Emergency Department Opioid Analgesic Prescribing Decisions.

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| S-EPMC4996790 | biostudies-literature

Longitudinal study of gene expression in healthy individuals

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2009-05-09 | GSE16028 | GEO

Sensitivity and other factors affecting biospecific desorption in chromatography of proteins. A study by computer simulation.

Project description:Some theoretical aspects of the desorption of a column-bound protein by elution with its biospecific ligand are considered in cases where, in comparison with the unliganded protein, the protein-ligand complex has a diminished but finite affinity for the adsorbent. A quantity termed the biospecific sensitivity, B, is introduced to facilitate comparison between different systems. Biospecific sensitivity may be defined as the fractional change in standard free energy of adsorption on formation of the protein-ligand complex. The effects of a moderate-to-low biospecific sensitivity on theoretical desorption profiles have been examined by using a computer simulation of the classical multiple-plate column model. Desorption was simulated under various boundary conditions involving protein-adsorbent and protein-ligand affinities and the initial concentrations of adsorption sites, protein and ligand. These simulations suggest that, when the biospecific sensitivity is low, desorption is optimized if (a) the unliganded protein is adsorbed as weakly as possible, (b) the column is loaded to near-saturation with the required protein, (c) the free ligand concentration is many times greater than that giving near-saturation of the protein in free solution, and (d) protein contaminants with high affinity for the adsorbent, and present in large amount, are removed in preliminary purification steps.

| S-EPMC1161286 | biostudies-other

Factors Affecting Metabolic Syndrome in Individuals With Chronic Spinal Cord Injury.

Project description:ObjectiveTo assess the validity of different anthropometric measures (waist circumference [WC], body mass index [BMI], and percentage body fat) in diagnosing metabolic syndrome (MetS) among individuals with SCI and provides preliminary data for future studies in setting obesity cutoff values for this population.MethodsThis was a single-center retrospective cohort study. Sample information, anthropometric measures, and MetS variables of 157 individuals with chronic SCI were collected from an electronic medical records database.ResultsIncreasing age (odds ratio [OR]=1.040, p=0.016) and lower neurological level of injury (OR=1.059, p=0.046) were risk factors for MetS. Male BMI (r=0.380, p<0.001) and male WC (r=0.346, p<0.001) were positively correlated with the number of MetS subfactors. Individuals with non-obese WC, excluding central obesity, were associated with having no MetS subfactors (p=0.005), and individuals with obese WC were associated with one or more subfactors (p=0.005). BMI was associated with MetS diagnosis (area under the curve=0.765, p<0.001), with the calculated cutoff value for BMI being 22.8 kg/m2.ConclusionThis study calls for a stricter BMI cutoff for individuals with SCI in diagnosing MetS and warrants a large population-based study to define central obesity according to sex and ethnicity.

| S-EPMC8913272 | biostudies-literature

The effects of intranasal oxytocin in opioid-dependent individuals and healthy control subjects: a pilot study.

Project description:RATIONALE:There has been an explosion of research on the potential benefits of the social neuropeptide oxytocin for a number of mental disorders including substance use disorders. Recent evidence suggests that intranasal oxytocin has both direct anti-addiction effects and pro-social effects that may facilitate engagement in psychosocial treatment for substance use disorders. OBJECTIVES:We aimed to assess the tolerability of intranasal oxytocin and its effects on heroin craving, implicit association with heroin and social perceptual ability in opioid-dependent patients receiving opioid replacement therapy (ORT) and healthy control participants. METHODS:We performed a randomized, double-blind, placebo-controlled, within- and between-subjects, crossover, proof-of-concept trial to examine the effects of oxytocin (40 international units) on a cue-induced craving task (ORT patients only), an Implicit Association Task (IAT), and two social perception tasks: the Reading the Mind in the Eyes Task (RMET) and The Awareness of Social Inference Test (TASIT). RESULTS:Oxytocin was well tolerated by patients receiving ORT but had no significant effects on craving or IAT scores. There was a significant reduction in RMET performance after oxytocin administration versus placebo in the patient group only, and a significant reduction in TASIT performance after oxytocin in both the patient and healthy control groups. CONCLUSIONS:A single dose of intranasal oxytocin is well tolerated by patients receiving ORT, paving the way for future investigations. Despite no significant improvement in craving or IAT scores after a single dose of oxytocin and some evidence that social perception was worsened, further investigation is required to determine the role oxytocin may play in the treatment of opioid use disorder. CLINICAL TRIAL REGISTRATION:Methadone Oxytocin Option. ClinicalTrials.gov identifier: NCT01728909.

| S-EPMC7452038 | biostudies-literature

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