SEARCH · PubMed Health

Results for “Color”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,297 records · Page 72Linked to original sources

PubMed1999

Estimation of heritabilities and correlations associated with milk color traits.

The objective of this study was to estimate the genetic parameters associated with milk color traits of dairy cattle. The data consisted of test day records of 9516 first lactation dairy cows and the records of 6358 of these cows that went on to produce a second lactation. Friesians, Jerseys, and crossbred cows were included in the data. Test day records included measures of milk, fat, and protein as well as milk color measured as absorbance at 450 nm. From these measurements, fat color and beta-carotene yield were calculated. Analyses were performed both within and across breeds. Jerseys produced more beta-carotene than did Friesians, and milk and fat from Jerseys had more intense color. Lactation model estimates for the heritabilities of milk color traits ranged from 0.33 to 0.44 (across breed), 0.40 to 0.49 (Friesians), and 0.17 to 0.31 (Jerseys). In all analyses, the heritability estimates associated with beta-carotene yield were lower than the estimates associated with the color of milk or fat. Genetic correlations between beta-carotene yield and the production traits were positive, but genetic correlations between fat color and production traits were generally negative. Genetic correlations between milk color and milk and protein yields were negative, and the correlations with fat yield were close to zero.

Animals↗

PubMed2002

Stroop interference effects in partially colored Stroop words.

In the Stroop task word reading is thought to be automatic since it runs without intentional monitoring and is difficult to avoid. This view has recently been challenged by observations that Stroop interference is reduced when only part of the Stroop word is colored. In this study we asked whether the extent of Stroop interference varies with the position of the colored letter(s). We observed that Stroop interference was smallest when the first letter(s) were colored and largest when either the last letter(s) or whole word were colored. On these findings we suggest that colored and noncolored parts of partially colored words are processed separately and differently, and that selection of the color dimension for explicit report entails inhibition of the to-be-ignored colored letters.

Humans↗

PubMedDate not supplied

Carotid artery disease assessed by color Doppler flow imaging: correlation with standard Doppler sonography and angiography.

Carotid artery disease was assessed in 180 patients by means of color Doppler flow imaging. Color Doppler findings in 360 carotid arteries were compared with the results of standard Doppler sonography, and color Doppler findings in 60 bifurcations were compared with the results of intraarterial angiography. The sensitivity of color Doppler for the detection of carotid disease was 100% when compared with angiography. The accuracy of color Doppler in classifying minor (40-60%), moderate (61-80%), and severe (81-90%) stenosis ranged from 91.3% to 97.8% vs standard Doppler sonography, and from 91.7% to 95.8% vs angiography. Whereas all occlusions were identified correctly by both color Doppler and angiography, four pseudoocclusions of the carotid artery were misdiagnosed as occluded. Characteristic features providing reliable criteria of the degree of stenosis are (1) intensity, extent, and duration of color fading; (2) postprocessed systolic peak frequency; (3) plaque extent on serial sonograms; and (4) poststenotic flow patterns. Display of hemodynamic disturbances induced by less pronounced plaques showed highly variable patterns that could not be anticipated from the plaque morphology alone. Thus, color Doppler preserves the advantages of standard Doppler and duplex sonography but provides additional information about otherwise anechoic necrotic and thrombotic material that often causes cerebral embolisms. With atherogenesis, repair mechanisms may be sustained or progression be stopped by reducing the risk factors and instituting medical treatment; thus, the application of this noninvasive technique is important.

Carotid Artery Diseases↗

PubMed1988

[Color Doppler sonography (angiodynography) in the assessment of the arterial vascular bed of the lower extremities].

With color Doppler ultrasonography, since its inception two years ago, through combination of color-coded flow and gray-coded vessel and tissue imaging, a new technique is available with which, based on the information derived from the Doppler principle, characterization is enabled of the direction of blood flow coded in red or blue, the velocity in varying color intensities and turbulent flow through color mixing. For determination of the velocity of flow at any point in the vessel, additionally, the pulsed Doppler method is available. The diagnosis of obstruction is based on delineation of plaques in the vascular lumen as well as changes in profile of the flowing blood. Color Doppler ultrasonography enables differentiation of high-grade stenosis from occlusion, aids and rapid localization of a stenosis and permits correction of the angle between the Doppler beam and flow in the vessel without providing quantitative evaluation of the degree of stenosis; the latter, however, can be mediated from the recorded velocity profile of the pulsed Doppler method Through demonstration of color-coded blood flow, the patency of bypass grafts can be documented. Additionally, information can be obtained with regard to the proximal and distal anastomoses, flow patterns in the region of preserve venous valves, stenoses and arterio-venous fistulas. Pseudoaneurysms are seen as cavity-like perivascular structures devoid of echo signals, the contiguous access to the lumen of which can be verified by display of pulsatile, systolic-diastolic flow in the color-coded image. With color Doppler ultrasonography abnormal flow patterns incurred through atherosclerotic changes in the vessel wall, stenoses, anastomoses, aneurysms and pseudoaneurysms can be reliably detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial Occlusive Diseases↗

PubMed1984

Classification of human senile cataractous change by the American Cooperative Cataract Research Group (CCRG) method: III. The association of nuclear color (sclerosis) with extent of cataract formation, age, and visual acuity.

Nineteen hundred and seventy-six immature human cataracts extracted intracapsularly were classified according to the Cooperative Cataract Research Group (CCRG) method of cataract classification. Data on cataract location and extent, nuclear color, preoperative visual acuity, age, and sex were organized and stored in the PROPHET system. The data were examined for relationships between nuclear color (sclerosis) and the age of the cataractous lens, the extent of opacification in seven anatomical regions including the degree of nuclear opacification and the preoperative visual acuity. Nuclear color correlates with age in a curvilinear manner. Nuclear yellowing increases gradually with increasing nuclear opacification, but the color change is so slight as to be useless for the purposes of inferring the intensity of nuclear opacification from the color of the nucleus. There is no association between the extent of anterior cortical, equatorial cortical, posterior cortical, subcapsular or supranuclear opacification, and nuclear color. Nuclear color impairs vision only for the range dark yellow through black. These data justify the recommendation that nuclear color be abandoned as the single index of the severity of any type of senile cataractous change.

Age Factors↗

PubMed1995

Transorbital color Doppler flow imaging of the carotid siphon and major arteries at the base of the brain.

PURPOSE: To describe and evaluate an application of sonography, transorbital color Doppler flow imaging of the carotid siphon and major intracranial arteries, and to compare it with transtemporal color Doppler flow imaging. METHODS: The carotid siphon and major arteries at the base of the brain of 50 healthy volunteers were screened using the transorbital color Doppler flow sonography. These arteries were also studied by a transtemporal approach for comparison. In 5 volunteers, MR images in special inclination planes were obtained and compared with the transorbital color-coded Doppler flow images. RESULTS: The B-mode image of the orbit and intracranial anatomic structures, in addition to the color-coded flow images, provided an unambiguous identification of the carotid siphon and major intracranial arteries. The failure rate was lower when using the transorbital approach than when using the transtemporal approach in identifying the anterior cerebral artery (17% versus 32%). Color Doppler flow imaging using the transtemporal approach was better for the middle cerebral artery, whereas color Doppler flow imaging using the transorbital approach was better for the anterior cerebral artery (contralateral). The Doppler incident angles using the transorbital approach were better for the carotid siphon and anterior cerebral artery (contralateral). CONCLUSION: Transorbital color Doppler flow imaging, when used in conjunction with the transtemporal examination, can add information concerning the major arteries at the base of the brain.

Adult↗

PubMed1975

The effect of metal ions on the atypical mycobacteria: growth and colony coloration.

The effect of 30 metal ions on growth and colony color has been evaluated for 215 isolates of "atypical" mycobacteria and 5 isolates of Mycobacterium tuberculosis. Of the total number of ions tested, ten proved to have a variable effect on growth and eight induced specific changes in colony coloration. Although both effects could be generally related to the Runyon grouping system, neither procedure proved to be practical or specific for differential identification of individual species. Spectrophotometric analyses of acetone extracts were made from representative strains of "atypical" mycobacteria, grown in the presence (test) or absence (control) of metal ions, in an attempt to determine the chemical nature of metal ion induced color changes in colonies of these organisms. Induced colors were not extractable with organic solvents, indicating that these colors are not lipid associated. In all cases where applicable (chromogenic strains) the naturally occurring carotenoid pigments were found to be unaffected, in their spectral properties, by the presence of metal ions even though the natural yellow color was frequently masked by the ion induced colors. The close association of metal ion induced colors with acetone nonextractable cell components suggests the presence of reduced metal ions or the formation of metal hydroxides. The apparent presence of several metal ion reductase systems and their physiological implications are discussed.

Metals↗

PubMed1996

[Determination of color pattern visual evoked potential in early primary open angle glaucoma].

OBJECTIVE: To evaluate the clinical significance of changes of color visual evoked potential (PVEP) in early primary open angle glaucoma (POAG). METHOD: Thirty-one patients (45 eyes) with POAG and fifty-one persons (94 eyes) as age-matched normal controls were tested by color PVEP. RESULTS: In POAG group, the latencies of P100 wave were lengthened, its amplitudes and wave form indexes decreased, the latencies of N145 wave were lengthened, and the amplitudes of N75 wave were lowered. In early POAG eyes without the changes detected by Goldmann perimetry, their color PVEPs were already abnormal. Stepwise regression analysis shows that four factors in color PVEP are correlated to the defect of visual field in POAG. It is proved with the stepwise discriminatory analysis that seven factors in the color PVEP are useful in the diagnosis of early POAG. CONCLUSIONS: Several factors in color PVEP are abnormal in POAG. In early POAG eyes without changes detected by Goldmann perimetry, their color PVEPs are already abnormal. By using discriminatory function, the positive rate of the diagnosis of early POAG tested by color PVEP might be increased.

Aged↗

PubMed1981

Congenital color blindness.

The term "color blind" is encountered frequently in areas pertaining to health, commerce, art, and entertainment, but in these cases it is generally not appropriate. Complete color blindness or achromasy is rare, but weakness or absence of discrimination to certain colors can be found in at least 8% of the male population. The most useful description of these color defects is in terms of hue and saturation, thresholds of which can be plotted as polar coordinates on a circular diagram. Plotting color thresholds with the chromagraph reveals more clearly than other clinical systems the true nature of color defects, as well as some inconsistencies in the traditional terminology and test methods. Fifty strongly color-defective subjects were tested by five different methods and the results compared. Normal values are also indicated.

Color Perception Tests↗

PubMed2001

Effects of low-level occupational exposure to styrene on color vision: dose relation with a urinary metabolite.

To investigate the threshold effects of chronic low-level occupational exposure to styrene on color vision, we examined color discrimination in 105 male workers exposed to styrene (mean age 37.7 years; mean length of exposure 6.2 years; mean urinary concentration of mandelic acid 0.21 g/L) and in 117 referents (mean age 37.7 years). We also assessed the effects of styrene by examination of the nature of the relation between disorders of nervous function and age, alcohol consumption, and other variables. A standardized questionnaire was adopted to collect information about work history, occupational or nonoccupational solvent exposure, alcohol consumption, and drug use. Color vision was evaluated by the Lanthony desaturated panel D-15 test. The results of the test were expressed as the color confusion index (CCI). There was a dose-dependent relationship between the urinary concentration of mandelic acid and color vision loss. The CCIs of the subgroups whose urinary mandelic acid levels were 0.1-0.2 and >0.2 g/L were significantly higher than those of each referent group (P<0.05 and P<0.01, respectively), but not in the subgroup whose urinary mandelic acid level was lower than 0.1 g/L. Our study suggests that a low level of styrene, presumably 0.1-0.2 g/L, involves the risk of inducing adverse effects on color vision. After confounding factors were adjusted for, the urinary mandelic acid level had a significant positive relationship with color vision.

Adult↗

PubMed2006

Longitudinal cohort study of patients with birdshot chorioretinopathy II: color vision at baseline.

PURPOSE: To describe color vision at the baseline examination of 80 participants in a longitudinal cohort study of birdshot chorioretinopathy and to identify relationships between color vision and visual acuity, symptoms, and ophthalmic signs. DESIGN: Single center cross-sectional study. METHODS: Color vision was evaluated with the desaturated Lanthony 15-Hue test. Relationships were sought between the square root of the color confusion scores (CCS) and the following factors: best-corrected visual acuity (BCVA), symptoms, cataract, vitreous inflammatory reactions, retinal vasculitis, cystoid macular edema (CME), and birdshot lesion characteristics. RESULTS: When compared with published, age-matched normal control subjects, 49 patients (61.3%; 76 eyes [47.5%]) had abnormal CCS values. Abnormal CCS values were found in nine of 51 phakic eyes (18%) with normal BCVA (>or=1.0) and without cataract. Although most eyes did not have classifiable defects, 30 eyes (18.8%) had tritan (blue-yellow) defects (88% of eyes with classifiable defects). With the use of multivariate analyses, there were significant associations between increased CCS values and the symptoms of altered color vision (P = .005) and altered contrast sensitivity (P = .015). There was a significant, but weak, relationship between CCS values and birdshot lesion morphologic condition (P = .049), but no relationships were found with other lesion characteristics or with vitreous inflammatory reactions, retinal vasculitis, or CME. CONCLUSION: The Lanthony 15-Hue test provides an objective technique to assess complaints of altered color vision in people with birdshot chorioretinopathy. Color vision can be abnormal in eyes with normal visual acuity; therefore, this parameter may be useful as an additional measure for monitoring the disease.

Adult↗

PubMed2005

Individual differences among grapheme-color synesthetes: brain-behavior correlations.

Grapheme-color synesthetes experience specific colors associated with specific number or letter characters. To determine the neural locus of this condition, we compared behavioral and fMRI responses in six grapheme-color synesthetes to control subjects. In our behavioral experiments, we found that a subject's synesthetic experience can aid in texture segregation (experiment 1) and reduce the effects of crowding (experiment 2). For synesthetes, graphemes produced larger fMRI responses in color-selective area human V4 than for control subjects (experiment 3). Importantly, we found a correlation within subjects between the behavioral and fMRI results; subjects with better performance on the behavioral experiments showed larger fMRI responses in early retinotopic visual areas (V1, V2, V3, and hV4). These results suggest that grapheme-color synesthesia is the result of cross-activation between grapheme-selective and color-selective brain areas. The correlation between the behavioral and fMRI results suggests that grapheme-color synesthetes may constitute a heterogeneous group.

Brain Mapping↗

PubMed2005

Associating color appearance with the cone chromaticity space.

A cone chromaticity space, a transform of a colorimetric specification system into coordinates that represent cone excitations, does not provide color appearance information. Boynton and Olson (Color Research and Application 12, 94-105, 1987) gathered color naming for the 424 Optical Society of America Uniform Color Scales (OSA-UCS) color samples. Here, a computational algorithm was developed that converts OSA-UCS sample values into L, M, S cone excitations based on the 1964 CIE 10 degrees Standard Observer. This makes it possible to plot the cone chromaticities associated with the eight color names used by Boynton and Olsen's observers to describe the non-dark appearing colors.

Algorithms↗

PubMed1996

An alternative to radioactive microspheres for measuring regional myocardial blood flow, Part 1: Colored microspheres.

OBJECTIVE: To compare measurements of regional myocardial blood flow between color and radioactive microspheres. DESIGN: Prospective, randomized, controlled. SETTING: University research laboratory. PARTICIPANTS: Pigs. INTERVENTIONS: Pigs underwent constriction of the left anterior descending artery, either incremental and then 0 constriction with epinephrine, 0.5 to 3 mu/kg/min (n = 5; "variable") or only 0% and 100% constriction without epinephrine (n = 4, "single"). Radioactive and color microspheres were injected simultaneously. For variable constriction, 5 colors (3 x 10(6)/mL) were tested in random order and, for single, red and yellow (6 x 10(6)/2 mL). MEASUREMENTS AND MAIN RESULTS: Measurements of regional endocardial, epicardial, and transmural myocardial blood flow were compared by regression analysis (linear and nonlinear). With radioactive measurements as the point of reference, when regional flow was 50 to 150 mL/min/100 g, correlation was high (r = 0.85), although regression slope was low. With endocardial and epicardial flow between 30 and 100 mL/min/100 g, correlation was close (r = 0.84). Overall nonlinear correlation was higher with single than variable constriction (r = 0.72). When regional flow was less than 100 mL/min/100 g, linear correlation was r = 0.72. When transmural flow measured by color microspheres was less than 25 mL/min/100 g, correlation was high (r = 0.86) but, with endocardial or epicardial flow, low (r = 0.67). When transmural flow was greater than 100 mL/min/100 g, correlation was extremely low (r = 0.1; n = 26 data points). The overall correlations for regional endocardial and epicardial flows were also low, except in the ischemic zone. CONCLUSIONS: Color and radioactive measurements correlate well during moderate and ischemic regional myocardial blood flow, ischemic blood flow requiring a higher concentration of color microspheres. A major limitation of using color microspheres is imprecision when flow is greater than 150 mL/min 100 g.

Animals↗

PubMedDate not supplied

Color mechanisms used in selecting stimuli for attention and making discriminations.

Previous work (Nagy & Thomas, 2003) showed that signals in different Cardinal color mechanisms could be combined to facilitate search for a color target. Further investigation (Nagy et al., 2003) suggested that signals in one Cardinal color mechanism were used to select a subset of stimuli to be attended, while signals in second Cardinal mechanism were used to discriminate the stimuli within the selected subset. In the studies described below, we asked if observers could use color mechanisms tuned to directions other than the Cardinal directions to select and discriminate stimuli. Observers searched for a single target stimulus that differed in chromaticity from nine distractor stimuli. A two-alternative forced-choice procedure was used to estimate thresholds. Results were consistent with the hypothesis that color mechanisms tuned to many different directions in color space mediate discrimination, but suggest that only signals in Cardinal mechanisms can be used to select stimuli for attention. Results imply that the selection of stimuli for attention on the basis of color may be mediated at the level of the lateral geniculate nucleus (LGN).

Attention↗

PubMedDate not supplied

Molecular genetics of color-vision deficiencies.

The normal X-chromosome-linked color-vision gene array is composed of a single long-wave-sensitive (L-) pigment gene followed by one or more middle-wave-sensitive (M-) pigment genes. The expression of these genes to form L- or M-cones is controlled by the proximal promoter and by the locus control region. The high degree of homology between the L- and M-pigment genes predisposed them to unequal recombination, leading to gene deletion or the formation of L/M hybrid genes that explain the majority of the common red-green color-vision deficiencies. Hybrid genes encode a variety of L-like or M-like pigments. Analysis of the gene order in arrays of normal and deutan subjects indicates that only the two most proximal genes of the array contribute to the color-vision phenotype. This is supported by the observation that only the first two genes of the array are expressed in the human retina. The severity of the color-vision defect is roughly related to the difference in absorption maxima (lambda(max)) between the photopigments encoded by the first two genes of the array. A single amino acid polymorphism (Ser180Ala) in the L pigment accounts for the subtle difference in normal color vision and influences the severity of red-green color-vision deficiency. Blue-cone monochromacy is a rare disorder that involves absence of L- and M-cone function. It is caused either by deletion of a critical region that regulates expression of the L/M gene array, or by mutations that inactivate the L- and M-pigment genes. Total color blindness is another rare disease that involves complete absence of all cone function. A number of mutants in the genes encoding the cone-specific alpha- and beta-subunits of the cGMP-gated cation channel as well as in the alpha-subunit of transducin have been implicated in this disorder.

Animals↗

PubMedDate not supplied

Cone contrasts do not predict color constancy.

A successive, asymmetric color-matching paradigm was used to investigate the link between cone contrast and the stability of perceived colors. We measured the perceived color shifts of 10 Munsell samples, induced by test illuminant A, simulated in u'v' color space. The capacity of the visual system to resist these shifts, otherwise known as color constancy, is measured in terms of the Brunswik ratio, BR. Cone contrasts are calculated with respect to either the physical or perceived background. Subjective cone contrasts show a better fit to the von Kries law than those based on the physical background. Complete cone adaptation occurs when color constancy is high. However we show conditions where cone adaptation seems complete but color constancy is poor.

Color↗

PubMed2004

Functional photoreceptor loss revealed with adaptive optics: an alternate cause of color blindness.

There is enormous variation in the X-linked L/M (long/middle wavelength sensitive) gene array underlying "normal" color vision in humans. This variability has been shown to underlie individual variation in color matching behavior. Recently, red-green color blindness has also been shown to be associated with distinctly different genotypes. This has opened the possibility that there may be important phenotypic differences within classically defined groups of color blind individuals. Here, adaptive optics retinal imaging has revealed a mechanism for producing dichromatic color vision in which the expression of a mutant cone photopigment gene leads to the loss of the entire corresponding class of cone photoreceptor cells. Previously, the theory that common forms of inherited color blindness could be caused by the loss of photoreceptor cells had been discounted. We confirm that remarkably, this loss of one-third of the cones does not impair any aspect of vision other than color.

Adult↗