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At least 235 records · Page 13Linked to original sources
PubMed2004

Risk factors for malignant melanoma in an Icelandic population sample.

OBJECTIVES: To describe the constitutional risk factors for malignant melanoma and exposure to sunlight in a population sample in Iceland. METHODS: Information on various risk factors for malignant melanoma was collected through mailed questionnaires sent to a random sample of the Icelandic population. The information collected was the first phase of a prospective study on malignant melanoma among aircrew members as compared to a population sample. RESULTS: The overall participation rate was about 50%. Seven percent of women and six percent of men had red hair color. Blue or green eye color was reported among 89% of women and 87% of men. Sixteen percent of women aged 20 to 39 had used sun beds more than 100 times during their lifetime, while the corresponding figure was 12% for men of the same age. Younger age groups had more sunny vacations than the older age groups. The frequency of sunburn differed in the groups with reported different skin types according to Fitzpatrick classification. CONCLUSION: The high prevalence of sun bed usage among young women is concurrent with the increased incidence of malignant melanoma among young women registered in the nationwide cancer registry. Young people have more often used sun beds and taken sunny vacation than the older, indicating a changed behavior in the population.

Adult↗
PubMed1982

Genetic instability in Drosophila melanogaster: deletion induction by insertion sequences.

Females of Drosophila melanogaster heteroallelic or homoallelic for X chromosome giant (gt) mutants generate deletions involving the wild-type alleles at two X chromosome gene loci: yellow body color (y) and white eye color (w). The deletions, bidirectional in the case of y and with fixed endpoint in the case of w, are associated with particular X chromosomes. Distinctive insertion sequences, located proximal to the target loci, are presumed to generate the deletions.

Animals↗
PubMed1991

The rosy locus in Drosophila melanogaster: xanthine dehydrogenase and eye pigments.

The rosy gene in Drosophila melanogaster codes for the enzyme xanthine dehydrogenase (XDH). Mutants that have no enzyme activity are characterized by a brownish eye color phenotype reflecting a deficiency in the red eye pigment. Xanthine dehydrogenase is not synthesized in the eye, but rather is transported there. The present report describes the ultrastructural localization of XDH in the Drosophila eye. Three lines of evidence are presented demonstrating that XDH is sequestered within specific vacuoles, the type II pigment granules. Histochemical and antibody staining of frozen sections, as well as thin layer chromatography studies of several adult genotypes serve to examine some of the factors and genic interactions that may be involved in transport of XDH, and in eye pigment formation. While a specific function for XDH in the synthesis of the red, pteridine eye pigments remains unknown, these studies present evidence that: (1) the incorporation of XDH into the pigment granules requires specific interaction between a normal XDH molecule and one or more transport proteins; (2) the structural integrity of the pigment granule itself is dependent upon the presence of a normal balance of eye pigments, a notion advanced earlier.

Animals↗
PubMed2005

Coloring our eyes.

Explore the source record for details and available documents.

Journal Article↗
PubMedDate not supplied

Aberrant segregation of R-locus genes in male progeny from incompatible crosses in Mormoniella.

Crosses of females from Mormoniella stocks containing pe-333 type cross incompatibility with males from stocks lacking the incompatibility produced progeny that included 29 males with unexpected eye colors. Eight of these males gave rise to stocks that included some individuals with "speckled" eyes, containing sectors or spots of different colors. In these stocks there were unexpectedly low frequencies of transmission of the new phenotypes to progeny. Phenotypes, and results of crosses, are consistent with the hypothesis that the original males and the stocks that they sired contained extra bits of chromatin contributed by the sperm of the males used in the incompatible crosses. In these stocks, these pieces are transmitted with greater frequency by sperm than by eggs, and are occasionally lost in mitosis (producing "speckled" eyes). Data also indicate that the extra chromatin contains only the O and S factors, or the O factor alone, of the eye color locus R. Examination of spermatogonia shows an extra piece of chromatin in cells of males with phenotypes that suggest the presence of such a piece. The piece has not been found in spermatogonia of controls.

Animals↗
PubMed1981

Angiotensin-converting enzyme activity in ocular fluids.

Angiotensin II is a biological active octapeptide that is formed by the action of angiotensin-converting enzyme (ACE) on the inactive precursor, angiotensin I. ACE activity was found in tears and aqueous humor from both rabbit and human eyes. The activity was higher in tears than aqueous humor. Enzyme activity was determined fluorimetrically from the rate of breakdown of the substrate, hippuryl-L-histidyl-L-leucine. The enzyme activity was further characterized by determining the effects of inhibitors. There was a significant difference in ACE levels in human tears when eye color was considered. People with either green or brown eyes had a higher ACE level than did blue-eyed individuals. The presence of this enzyme activity in ocular fluids suggests that angiotensin II may play a role in normal ocular physiology.

Angiotensin I↗
PubMed1981

Latency differences in monoptic and dichoptic shape and color decision making.

Past research based on the McCollough effect and efficacy of chromatic cues in stereopsis suggests that color information is difficult to process binocularly as compared to form information. This study evaluates this proposition using a reaction time paradigm. Subjects decided whether two simultaneous visual stimuli were the same in shape or color. With presentation to the same eye, color reaction times led shape latencies. Presenting one target to one eye and one to the other slowed color times. Delaying one target by 500 msec yielded dichoptic and monoptic color decisions faster than shape. The results are related to the relationships of color and contrast pathways and possible differences in binocular rivalry.

Color Perception↗
PubMed1990

Reduced mydriasis from repeated doses of tropicamide and cyclopentolate.

Pupils are often dilated for examination the day before surgery and again on the day of surgery. The following experiment was performed to determine the effect of serial doses of two commonly used mydriatic agents: on two consecutive days the pupil of one of the eyes of 28 subjects was dilated with tropicamide 1%, and the pupil of one of the eyes of 30 subjects was dilated with cyclopentolate hydrochloride 1%. The other eyes in both groups were dilated only on the second day, and thus served as controls. Pupil sizes were measured from photographs before and after dilation. The pupils of the eyes treated twice with either drug did not dilate as well after the second dose as those of the control eyes (P less than .005 for tropicamide, P less than .001 for cyclopentolate). The pupils of the eyes twice-treated with tropicamide were an average of 0.15 mm smaller than the control pupils; those twice-treated with cyclopentolate were 0.36 mm smaller. For subjects treated with cyclopentolate, this decreased mydriasis was related to age (P less than .05) and to eye color (P less than .025): the younger and blue-eyed subjects dilated less on the second day than the older and brown-eyed subjects. If full mydriasis is required at surgery, pupils should probably not be dilated with either tropicamide or cyclopentolate the day before surgery.

Adult↗
PubMed1979

["Basic brown", a too little considered iris color].

The eye colour is mainly effected by the two components melanin and structural blue of the iris stroma which generally are present in various mixtures respectively combinations. Are these components lacking the dark pigment epithelium can produce a so-called "basic brown". The exact distinction between "brown" and "basic brown" is without doubt of considerable value for anthropological as well as for genetical examinations of eye colours.

Eye Color↗
PubMed2006

t(14;18) translocations in lymphocytes of healthy dioxin-exposed individuals from Seveso, Italy.

Dioxin exposure has been associated with non-Hodgkin's lymphoma (NHL) in epidemiological investigations. The NHL-related t(14;18) translocations can be detected at a low copy number in lymphocytes from healthy subjects. Exposure to NHL-associated carcinogens, such as dioxin or pesticides, may cause expansion of t(14;18)-positive clones. We investigated prevalence and frequency of circulating t(14;18)-positive lymphocytes in 144 healthy subjects from a population exposed to dioxin [plasma TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) range: <1.7-475.0 parts per trillion (p.p.t.)] after the Seveso, Italy, accident of 1976. t(14;18) translocations were measured in DNA from peripheral blood lymphocytes by high-sensitivity real-time quantitative polymerase chain reaction. We found that the frequency, but not the prevalence, of t(14;18) translocation-positive cells increased with increasing plasma TCDD. Among t(14;18)-positive subjects (n = 50;34.7%), the mean number of t(14;18) translocations/10(6) lymphocytes was 4.2 [95% confidence interval (CI), 2.9-6.2] in subjects with plasma TCDD < 10.0 p.p.t., 8.1 (95% CI, 4.9-13.3) in subjects with plasma TCDD between 10.0 and 50.0 and 12.5 (95% CI, 7.4-21.1) in subjects with plasma TCDD between 50.0 and 475.0 p.p.t. (P-trend = 0.003). As expected, t(14;18) frequency was associated with cigarette smoking and was highest in subjects who smoked for > or =16 years (mean = 12.6; 95% CI, 7.4-21.3; P = 0.01). Higher t(14;18) prevalence was found among individuals with fair hair color (P = 0.01) and light eye color (P = 0.04). No significant association between t(14;18)-and age was found. Our results show that dioxin exposure is associated with increased number of circulating t(14;18) positive cells. Whether this change in t(14;18) frequency is an indicator of elevated lymphoma risk remains speculative and needs further investigation for its potential impact on public health.

Adolescent↗