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PubMed1988

Production of chimeric rabbits from morulae by a simple procedure.

Experiments were conducted to develop a simple and reliable technique to produce chimeric rabbits from morula stage embryos. In Experiments 1 and 2, an in-vitro test of viability was initially performed by culturing embryos to the blastocyst stage. Ninety-three percent of the "chimeric" embryos developed to the blastocyst stage compared to 94% for controls when embryos were manipulated soon after collection (Exp. 1). Eight-one percent chimeric embryos and 78% control embryos developed to blastocyst stage when embryos were held at room temperature for 4 hr (Exp. 2). In Experiment 3, enough morula-stage embryos were available from true breeding Dutch-belted and albino rabbits to form potentially 67 diverse "color" pairs. These micromanipulated pairs of morulae were successfully combined to produce 64 chimeric embryos (96%, 64/67). They were transferred to the uteri of seven recipient does and three became pregnant producing 13 young. Four of the young exhibited substantial overt chimerism (31%) and one more was a possible chimera.

Animals↗
PubMed2004

Genetic correlations among texture characteristics in the human iris.

PURPOSE: To estimate the magnitude of genetic correlations among five general textural characteristics of the human iris. METHODS: Color photographs of iris were available from 100 monozygotic and 99 dizygotic twin pairs. Comparative scales were constructed based on ratings of the subjects' left iris. To explore the genetic and environmental covariation among frequency of Fuchs' crypts, frequency of pigment dots, iris color, the extension, and distinction of Wolfflin nodules, and contraction furrows, a structural equation model with Cholesky decomposition was applied to variance-covariance matrices for monozygotic (MZ) and dizygotic (DZ) pairs. RESULTS: Significant genetic correlations fell between -0.22 and 0.44 and accounted almost entirely for the phenotypic correlations among the iris characteristics. No evidence for individual specific environmental effects in common to the characteristics was found. CONCLUSIONS: The modest genetic correlations indicate that there is little overlap in the genetic influence for these characteristics. Candidate genes with embryological and histological expression patterns in the eye could potentially influence the iris characteristics' variability.

Adolescent↗
PubMed1994

Dermatography as a modern treatment for coloring leucoma corneae.

Since antiquity many attempts were made and hence many methods were devised to minimize the disfiguration and stigmatization caused by leucoma corneae. Dermatography, a refined, modified tattooing technique, was used successfully in three cases of leucoma corneae. The materials and method are safe and simple. Over a 3-year follow-up period, no negative reactions were found. The cosmetic results were very satisfactory.

Adult↗
PubMed1994

[Color duplex ultrasound findings in patients with endocrine orbitopathy].

UNLABELLED: Color Doppler imaging makes it possible for the first time to assess the blood flow velocity of orbital vessels. Especially in Graves disease, with its increase of orbital contents, this technique allows detection of changes in the perfusion of retrobulbar arteries and veins. We examined 23 patients (19 female, 4 male, average age 47.9 years) with thyroid ophthalmopathy using color Doppler imaging. Central retinal artery and vein, posterior ciliary arteries, vortex veins, superior orbital vein and ophthalmic artery were located and their Doppler spectra analysed. Results were compared with observations recorded in a control group consisting of 105 healthy volunteers. The thicknesses of extraocular muscles were measured echographically. RESULTS: There was no significant difference in blood flow velocity in central retinal artery and vein, posterior ciliary arteries and vortex veins between patients with Graves disease and the control group. The maximal blood flow velocity in superior orbital vein was significantly decreased (P = 0.01 on right eye, P = 0.04 on left eye). There was a slight correlation between reduced venous outflow in the superior orbital vein and the severity of the disease (r = 0.52 on right eye, r = 0.5 on left eye). CONCLUSION: Color Doppler imaging is a new, noninvasive technique that could be used to examine patients with thyroid ophthalmopathy. Reduced venous outflow may contribute to exophthalmus by creating perivenous edema and consequent swelling of orbital fat.

Adult↗
PubMed2006

A family with X-linked optic atrophy linked to the OPA2 locus Xp11.4-Xp11.2.

Autosomal dominant optic atrophy (ADOA) is the most common inherited optic atrophy. Clinical features of ADOA include a slowly progressive bilateral loss of visual acuity, constriction of peripheral visual fields, central scotomas, and color vision abnormalities. Although ADOA is the most commonly inherited optic atrophy, autosomal recessive, X-linked, mitochondrial, and sporadic forms have also been reported. Four families with X-linked optic atrophy (XLOA) were previously described. One family was subsequently linked to Xp11.4-Xp11.2 (OPA2). This investigation studied one multi-generation family with an apparently X-linked form of optic atrophy and compared their clinical characteristics with those of the previously described families, and determined whether this family was linked to the same genetic locus. Fifteen individuals in a three-generation Idaho family underwent complete eye examination, color vision testing, automated perimetry, and fundus photography. Polymorphic markers were used to genotype each individual and to determine linkage. Visual acuities ranged from 20/30 to 20/100. All affected subjects had significant optic nerve pallor. Obligate female carriers were clinically unaffected. Preliminary linkage analysis (LOD score = 1.8) revealed that the disease gene localized to the OPA2 locus on Xp11.4-Xp11.2. Four forms of inherited optic neuropathy, ADOA, autosomal recessive optic atrophy (Costeff Syndrome), Leber hereditary optic neuropathy, and Charcot-Marie-Tooth disease with optic atrophy, are associated with mitochondrial dysfunction. Future identification of the XLOA gene will reveal whether this form of optic atrophy is also associated with a mitochondrial defect. Identification of the XLOA gene will advance our understanding of the inherited optic neuropathies and perhaps suggest treatments for these diseases. An improved understanding of inherited optic neuropathies may in turn advance our understanding of acquired optic nerve diseases, such as glaucoma and ischemic optic neuropathy.

Chromosomes, Human, X↗
PubMed2003

Sequences associated with human iris pigmentation.

To determine whether and how common polymorphisms are associated with natural distributions of iris colors, we surveyed 851 individuals of mainly European descent at 335 SNP loci in 13 pigmentation genes and 419 other SNPs distributed throughout the genome and known or thought to be informative for certain elements of population structure. We identified numerous SNPs, haplotypes, and diplotypes (diploid pairs of haplotypes) within the OCA2, MYO5A, TYRP1, AIM, DCT, and TYR genes and the CYP1A2-15q22-ter, CYP1B1-2p21, CYP2C8-10q23, CYP2C9-10q24, and MAOA-Xp11.4 regions as significantly associated with iris colors. Half of the associated SNPs were located on chromosome 15, which corresponds with results that others have previously obtained from linkage analysis. We identified 5 additional genes (ASIP, MC1R, POMC, and SILV) and one additional region (GSTT2-22q11.23) with haplotype and/or diplotypes, but not individual SNP alleles associated with iris colors. For most of the genes, multilocus gene-wise genotype sequences were more strongly associated with iris colors than were haplotypes or SNP alleles. Diplotypes for these genes explain 15% of iris color variation. Apart from representing the first comprehensive candidate gene study for variable iris pigmentation and constituting a first step toward developing a classification model for the inference of iris color from DNA, our results suggest that cryptic population structure might serve as a leverage tool for complex trait gene mapping if genomes are screened with the appropriate ancestry informative markers.

Chromosomes, Human, Pair 10↗
PubMed1992

[The color and structure of the human iris. 1. Morphological studies].

The material basis of this investigation consists of empirical findings and colour photographs of the irises of 200 pairs of twins and 100 control pairs. For the morphological investigation first-born twins and control persons are combined to constitute a comparative group of 400 non-related testees. Research by means of the iris microscope and the evaluation of standardized iris photographs led to the development of a catalogue of features which describes 10 iris characteristics for the iris colour and 20 for the iris structure. For each feature different degrees of markedness are defined and their frequency is determined. Similarly, intraindividual right/left and sex differences as well as age-dependencies and the relation between the features are examined. The setting-up of features includes outlining an iris-colour class system in order to render a better and more practicable determination of eye colour possible. As a substitute for Martin/Schulz's table of eye-colour, which describes only eye-colour phenomena, 4 iris-colour classes are set up whose main criterion of classification is the quantity of pigment. When we consider the testees of all age classes, sex differences have no statistical relevance as for iris colour. Only in the case of male testees may an intensive decrease of blue and brown iris colour in favour of combination colours (yellow pigment colours in particular) be observed during the phase of puberty. Therefore, the brightening postulated in the relevant literature can be confirmed. With regard to female testees, in contrast, pigment shifting is of no statistical relevance. After a slight brightening the irises numerically re-darken at the adult-stage to the initial child level, i.e. they become "dark again" rather than just become "darker". Within the iris structure only the characteristics of the anterior stroma leaf show sex differences. They are, however, only weakly marked and can be described merely as a trend. Over the whole range of the age classes, there are no outstanding structural differences. The different iris characteristics concerning iris colour stand in a significant relation to each other. When we consider the statistically relevant relations between structural features, it becomes clear that particularly reduced and particularly intact iris characteristics correlate. Thus, we can distinguish between an intact type of iris and a reduced one. Three quarters of the testees, however, combine reduced and intact properties with medium degrees of markedness.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1987

The aging eye. A family physician discusses some inevitable changes and suggests methods for dealing with them.

The aging eye undergoes a variety of structural and physiologic changes that can impair vision and cause functional disability. Among the changes are backward displacement of the eye into the orbit, thickening and yellowing of the lens, decrease in pupil size, increase in laxity of the lids, and accumulation of waste products in the retina. The specific diseases of the eye that occur with aging include macular degeneration, cataracts, glaucoma, diabetic retinopathy, and sudden vision loss. Preventive care both in old age and earlier in life may help forestall ocular changes and the subsequent morbidity and mortality they cause. Environmental changes to accommodate visual change can be important in accident prevention and in improved functioning and quality of life.

Aged↗
PubMed1992

Expression of tyrosinase gene in transgenic albino mice: the heritable patterned coat colors.

To elucidate the regulatory mechanism for tyrosinase gene expression in vivo, we microinjected a mouse tyrosinase minigene, mg-Tyrs-J, into the fertilized eggs of BALB/c albino mice. As a result, we obtained six pigmented founder mice that exhibited non-standard coat color variations as well as the wild-type phenotype. These founder mice were subsequently crossed with BALB/c albino mice to establish the transgenic lines. As a consequence, two primary lines and five sublines have been obtained from four of the six founder mice. We found that not only uniformly pigmented phenotypes but also patterned phenotypes were inherited by their descendants. The possible underlying mechanism of the patterned phenotypes is discussed.

Albinism↗
PubMed2002

Visual search in patients with left visual hemineglect.

In patients with hemi-spatial neglect eye movement patterns during visual search reflect not only inattention for the contralesional hemi-field, but interacting deficits of multiple visuo-spatial and cognitive functions, even in the ipsilesional hemi-field. Evidence for these deficits is presented from the literature and from saccadic scan-path analysis during feature and conjunction search in 10 healthy subjects and in 10 patients with manifest or recovered left visual neglect due to right-hemispheric stroke. Deficits include (1) a rightward shift of spatial representation, (2) deficient spatial working memory and failure of systematic search strategies, leading to multiple re-fixations, more after frontal lesions, and (3) a reduced spotlight of attention and a deficient pop-out effect of color, more after temporo-parietal lesions.

Adult↗
PubMed1982

Race, iris pigmentation, and intraocular pressure.

The association of intraocular pressure with age, sex, race, iris pigmentation, systemic blood pressure, and family income was evaluated using data from the Health and Nutrition Examination Survey of 1971-1972. In general, mean intraocular pressure was highest for blacks with brown irides and progressively lower for whites with brown irides, whites with neither brown nor blue irides, and whites with blue irides. Multilinear regression analysis showed positive associations of intraocular pressure with systolic blood pressure (p less than 0.0001), age (p less than 0.0001) and amount of iris pigmentation (p less than 0.0001). The association with iris pigmentation held for both a combined race/iris color variable and for iris color among white persons. When race rather than iris pigmentation was used in the regression equation, it was a weaker (p less than 0.03) but still significant risk factor for higher levels of intraocular pressure. Intraocular pressure was negatively associated with family income (p less than 0.004). Despite the significant associations, the proportion of variance in intraocular pressure that was explained by these variables was small (R2 = 0.06).

Adult↗
PubMed1989

Hypopigmentation: a common feature of Prader-Labhart-Willi syndrome.

In order to determine the frequency and characterization of hypopigmentation in Prader-Labhart-Willi syndrome (PLWS), clinical, cytogenetic and biochemical findings are reported in 56 PLWS individuals. Forty-eight percent of the individuals with PLWS met the criteria for hypopigmentation. Hypopigmentation in PLWS individuals appears to be as common as previously recognized features such as behavioral problems and dental abnormalities. Significant differences in hair color, sun sensitivity, and complexion were found between those PLWS patients with the chromosome 15 deletion and those with normal chromosomes. Individuals with the deletion frequently had lighter hair color, more sun sensitivity, and fairer complexion than did either other family members or nondeletion PLWS patients. No significant differences in biochemical findings (phenylalanine, tyrosine, catecholamines, or beta-melanocyte-stimulating hormone) were found between deletion and nondeletion PLWS patients or between hypopigmented and normally pigmented patients. The data suggest that a gene(s) controlling the activity of tyrosinase or other enzymes required for melanin production is located on proximal 15q.

Adolescent↗
PubMed1998

Scotopic sensitivity: relation to age, dietary patterns, and smoking status.

PURPOSE: Although previous data suggest that rod-mediated sensitivity decreases with age, this decrease may be insignificant when only healthy individuals younger than 65 years are considered. In this study, we assess the relationship between age and scotopic sensitivity loss in subjects younger than 65 years to determine whether scotopic sensitivity losses can be detected when confounding factors are considered (including iris color, smoking status, and dietary patterns) and a large sample size is used. METHODS: A total of 121 subjects (aged 20 to 63 years) were tested under dark-adapted (scotopic) conditions. Scotopic sensitivity was measured as absolute thresholds to a 2.8 degree, 550-nm test presented at 6 degrees in the temporal hemiretina. Stimuli were presented in Maxwellian view. RESULTS: When all the subjects were considered together, there was a slight nonsignificant trend for scotopic sensitivity to decline with age (p < 0.11). This tendency was largely driven by the older (45 to 63 years) past and never smokers and was statistically significant (p < 0.024 and p < 0.05, respectively) when those two groups were analyzed separately. Scotopic sensitivity for the younger (20 to 44 years) past, current, and never smokers did not decline with age. When all the variables were considered in a general model, dietary intake of vitamin E explained a significant amount of the variation in scotopic sensitivity (p < 0.03). No relationships were found between scotopic sensitivity and iris color. CONCLUSIONS: Age-related losses in scotopic sensitivity before age 65 are slow. Moreover, individual variations in scotopic sensitivity for younger subjects is minimal, even in the presence of dramatic stressors such as long-term, heavy exposure to cigarette smoke. These data suggest that measurements of scotopic sensitivity may not be good indicators of the retinal health of individuals younger than 65 years.

Adult↗
PubMed1978

[Clinical aspects and therapy of the posner-schlossmann-syndrom (author's transl)].

UNLABELLED: Difficulties in the early diagnosis of the Posner-Schlossmann syndrome can be avoided by looking for the following typical clinical signs: Very fine, unpigmented precipitates, which are often only signly present, and which are scattered over the entire cornea: bright white in incident light, translucent in reflected light, and in transmitted light dark in spots. Posterior synechiae are not present. Obvious differences in color or heterochromia are present in only 30-40% of the cases. In the remaining cases, there ist only a slight color difference or unilateral, diffusely trophic hypochromia of the iris, often only after several attacks. The chamber angle is and remains open during the attacks. There are similarities between glaucomatocyclitic crisis and heterochromic cyclitis: Unilaterality, the same specific precipitates, no synechiae, and practically the same percentage of color differences of the iris. Hypochromic dystrophy of the iris dependent on the magnitude and duration of the cyclitic process. In both cases, there is the same rate of physical changes, pointing to a congenital damage of the sympathetic nervous system (status dysraphicus Passow). Hence, the Posner-Schlossmann syndrome can be regarded as a special case of heterochromic cyclitis. THERAPY: Neither miotics nor mydriatics, nor operation during the crisis. Acetazolamide (Diamox) combined with local cortisone will stop the crisis.

Adult↗
PubMed2003

A prospective study of pigmentation, sun exposure, and risk of cutaneous malignant melanoma in women.

BACKGROUND: Although sun exposure is an established cause of cutaneous malignant melanoma, possible interactions with host factors remain incompletely understood. Here we report the first results from a large prospective cohort study of pigmentation factors and sun exposure in relation to melanoma risk. METHODS: The Women's Lifestyle and Health Cohort Study included 106 379 women from Norway and Sweden who were aged 30-50 years in 1991 or 1992 when they completed an extensive questionnaire on personal characteristics and exposures. Linkages to national registries ensured complete follow-up through December 31, 1999. Poisson regression models were used to estimate relative risks (RRs). All statistical tests were two-sided. RESULTS: During an average follow-up of 8.1 years, 187 cases of melanoma were diagnosed. Risk of melanoma was statistically significantly associated with increasing body surface area (RR for > or =1.79 m2 versus < or =1.61 m2 = 1.60, 95% confidence interval [CI] = 1.03 to 2.48; P(trend) =.02), number of large asymmetric nevi on the legs (RR for > or =7 nevi versus 0 nevi = 5.29, 95% CI = 2.33 to 12.01; P(trend)<.001), hair color (RR for red versus dark brown or black = 4.05, 95% CI = 2.11 to 7.76; P(trend)<.001), sunburns per year at ages 10-19, 20-29, and 30-39 years (P(trend)<.001, P(trend) =.03, and P(trend) =.05, respectively), and use of a device that emits artificial light (solarium) one or more times per month (P =.04). CONCLUSIONS: Our results confirm previous findings that hair color, number of nevi on the legs, and history of sunburn are risk factors for melanoma and suggest that use of a solarium is also associated with melanoma risk. Adolescence and early adulthood appear to be among the most sensitive age periods for the effects of sunburn and solarium use on melanoma risk. However, it may be too early to see the full effect of adult exposures in this cohort.

Adolescent↗
PubMed2000

Stimulus frequency affects c-fos expression in the rat visual system.

We have characterised the c-fos expression patterns in various centers of the visual pathway of adult rats monocularly stimulated either by continuous or flickering light at different frequencies. Results show different immunocytochemical patterns in all centers studied, the geniculate lateral complex (LGC), superior colliculus (SC) and primary visual cortex (Oc1), depending on the physical characteristics of the stimulus (blinking frequency and light wavelength). After stimulation of the left eye, the ipsilateral pathway presents a substantial density of immunoresponsive cells, which is greater than expected with respect to the number of fibers that project ipsilaterally from the retina to the LGC and the superficial layers of the SC. A surprisingly high positive immunoresponsiveness is obtained in all cases with coherent light stimulation in the red spectrum (634 nm).

Animals↗
PubMedDate not supplied

Pupil size in Jewish theological seminary students.

PURPOSE: To investigate the authors' clinical impression that pupil size among myopic Jewish theological seminary students is different from pupil size of similar secular subjects. METHODS: This cross-sectional study was conducted on 28 male Jewish theological seminary students and 28 secular students or workers who were matched for age and refraction. All participants were consecutively enrolled. Scotopic and photopic pupil size was measured by means of a Colvard pupillometer. Comparisons of various parameters between the groups were performed using the two-sample t-test, Fisher exact test, a paired-sample t-test, a two-way analysis of variance, and Pearson correlation coefficients as appropriate. RESULTS: The two groups were statistically matched for age, refraction, and visual acuity. The seminary students were undercorrected by an average of 2.35 diopters (D), while the secular subjects were undercorrected by only 0.65 D (p<0.01). The average pupil size was larger in the religious group under both scotopic and photopic luminance. This difference was maintained when the two groups were compared according to iris color under both conditions, reaching a level of statistical significance (p<0.0001). There was a significant difference in photopic pupil size between dark and light irises (p=0.049), but this difference was not maintained under scotopic conditions. CONCLUSIONS: The average pupil size of young ultraorthodox seminary students was significantly larger than that of matched secular subjects. Whether this is the result of intensive close-up work or of apparently characteristic undercorrection of the myopia is undetermined.

Adult↗