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At least 1,297 records · Page 72Linked to original sources
PubMed2007

Common melanocytic nevi in 7-year-old schoolchildren residing at different latitudes in Sweden.

BACKGROUND: Current epidemiologic research shows consistently that increased number of acquired common melanocytic nevi (CMN) is an important risk factor for cutaneous malignant melanoma. The purpose of this study was to investigate the number of CMN in relation to tanning habits and complexion among 7-year-old children residing at different latitudes in Sweden. METHODS: Two municipalities were chosen at latitude 65 degrees N to 68 degrees N in the north of Sweden and two at latitude 57 degrees N in the south. Children born in 1994 and registered in the municipalities were to be included (N = 1,676). A questionnaire was sent to their parents asking about the child's tanning habits. A body examination of CMN of size >or=2 mm was done by the same trained nurse in 1,380 (82.3%) of the children. RESULTS: CMN was significantly less prevalent among children living in the north with a prevalence of 5.6 [95% confidence interval (95% CI), 4.8-6.5] inland and 6.2 (95% CI, 5.3-7.2) coastal compared with the south with a prevalence of 9.5 (95% CI, 8.2-11.0) inland and 10.4 (95% CI, 8.9-12.0) coastal. In addition, blond hair, blue/gray/green eyes, holidays at seaside resorts abroad, more frequent sunburns, and parents fancying tanning were significant predictors of higher prevalence of CMN. CONCLUSIONS: These findings support previous evidence that the development of CMN is related to the level of sun exposure in childhood expressed as latitude of residence, holidays at seaside resort abroad, and number of sunburns. To reduce the incidence of cutaneous malignant melanoma, a change in attitude and behavior must start with young children and their parents.

Child↗
PubMedDate not supplied

Adaptation-dependent differences in electroretinographic latency patterns in uniform and variegated horseshoe crabs.

The carapaces of horseshoe crabs (Limulus polyphemus) differ. Some individuals have uniform carapaces and clear eyes while others have variegated carapaces and dark eyes. These differences have been reported to be correlated with latency differences in the electroretinogram (ERG) of the lateral eye. Such a result might have had a neural basis in the mechanisms underlying visual transduction but it could also have reflected a visual screening pigment difference. A direct experiment was therefore designed to choose between these two hypotheses by varying the relative state of adaptation. The results were as follows. In uniform animals, dark adaptation had the kind of effect seen in single photoreceptor cells - latencies were longer in dark-adapted eyes and latencies were also longer for dim flashes. However, variegated animals showed a significant adaptation interaction: in light adaptation, dimmer flashes produced the usual effect, namely a longer ERG latency, while in dark adaptation, latencies were close to equilatent, being within experimental error of each other for both flash energies. These data make it unlikely that the photoreceptor transduction mechanism is the locus of the visual differences between the two types of animals. Instead, they are consistent with an interaction of screening pigment effects with photoreceptor transduction effects.

Adaptation, Physiological↗
PubMed1999

Iridology: A systematic review.

BACKGROUND: Iridologists claim to be able to diagnose medical conditions through abnormalities of pigmentation in the iris. This technique is popular in many countries. Therefore it is relevant to ask whether it is valid. AIM: To systematically review all interpretable tests of the validity of iridology as a diagnostic tool. DATA SOURCE AND EXTRACTION: Three independent literature searches were performed to identify all blinded tests. Data were extracted in a predefined, standardized fashion. MAIN RESULTS: Four case control studies were found. The majority of these investigations suggests that iridology is not a valid diagnostic method. CONCLUSION: The validity of iridology as a diagnostic tool is not supported by scientific evaluations. Patients and therapists should be discouraged from using this method.

Case-Control Studies↗
PubMed1975

Anterior chamber of the eye. A genetic and anthropological study in Greenland Eskimos.

During a population survey in Eskimos family resemblance with respect to anterior chamber depth (ACD) was studied. Heritability estimates of about 0.7 against a marital correlation of zero were obtained. No correlation between ACD and parity, but a significant correlation with stature was found which possibly accounts for the sex difference in ACD. Significant associations between ACD, iris colour, facial appearance, and corneal diameter were observed. West Greenlanders with a predominantly Eskimoan physiognomy showed smaller anterior chambers than unmixed East Greenland Eskimos and Eskimo-Caucasian hybrids.

Adolescent↗
PubMed1989

Frequency of acquired melanonevocytic nevi and their relationship to skin complexion in 939 schoolchildren.

In 939 schoolchildren aged 8-16 years skin complexion was determined by a system of seven categories Anamnestic data concerning tanning ability and history of sunburns, however, were not considered owing to their obvious unreliability in children. Mean nevus count was 17.97, was significantly higher in boys than in girls and increased with age. There was a clear relation of mean nevus number and skin complexion: in fair skin type nevi are most frequent, decreasing in number by increasing of pigment content. Additionally, children with freckles have higher mean nevus count in every category of skin complexion. All literature data critically reviewed as dealing with mean mole count are not comparable in several respects. In different races, however, such studies may serve as a basis for subsequent investigations concerning the questions of probably increasing number of melanonevocytic nevi.

Adolescent↗
PubMed1992

Waardenburg syndrome in Japanese patients. Case reports and literature review.

A 3-year-old girl (case 1) had a blue iris and albinotic fundus in the right eye and bilateral deafness. Her 6-month-old sister (case 2) had hypopigmented irides and fundi in both eyes and bilateral deafness. We found that the ratios of interinner canthal distance to interpupillary distance were less than 0.65 in normal Japanese controls. In our patients, these ratios were within the normal range, indicating the absence of dystopia canthorum. After reviewing the recent Japanese literature, we found that the hypopigmented iris and deafness seen in our patients are common in Japanese patients with Waardenburg syndrome.

Adult↗
PubMed1996

Branch retinal vein occlusion in a patient with Waardenburg syndrome.

A 43-year-old woman (case II-2) with dystopia canthorum, white forelock, blue iris in the left eye, hypopigmented fundi, and systemic hypertension complained of visible floaters in the left eye. Whitish branch retinal vein, preretinal hemorrhages and neovascularization were found in the left fundus. Her intraocular pressure in the left eye was sometimes elevated to 22 mm Hg. The patient's brother (case II-3) was reported to have blue irises in both eyes. We believe that these patients have Waardenburg syndrome, that branch retinal vein occlusion in case II-2 may be caused chiefly by systemic hypertension, and that elevated intraocular pressure associated with the blue iris may be partly involved in the pathogenesis of vein occlusion in the left eye.

Adult↗
PubMed1996

Assignment of genes coding for brown eye colour (BEY2) and brown hair colour (HCL3) on chromosome 15q.

Brown eye colour (BEY), or total brown iris pigmentation is one of the most common phenotypes of iris colour. Data of eye colour as well as hair colour were obtained for linkage analysis through an enquiry in our family material of 832 families from Copenhagen area. By exclusion mapping with 80 markers in 120 segregating families and 290 markers in 5 segregating families, we obtained some indication of a locus BEY2 for brown eye colour on chromosome 15. For possible confirmation, we selected a total of 45 families from our DNA bank segregating for BEY. All these were tested for chromosome 15 markers in the area between D15S11 and CYP19. We found a strong indication of tight linkage with the DNA polymorphism D15S165 (Z = 24.25; theta M = F = 0.010) and with the flanking markers D15S156 (Z = 14.04; theta M = F = 0.0.029) and D15S144 (Z = 12.99; theta M = F = 0.060). BEY2 is assigned to the region 15q11-15q21 by physically localized markers. A new locus for brown hair colour (HCL3) was localized by indication of linkage to BEY2 in our 45 families segregating for BEY (Z = 9.93; theta M = F = 0.10). The gene (DN10 or P) homologous to the pink-eye-dilution gene (p) in mice could be a candidate gene for BEY2 or for HCL3.

Chromosome Mapping↗
PubMed2006

Vernier acuity of illusory contours defined by motion.

We present here a series of experiments exploring a special class of visual completion that is strictly tied to the perception of apparent motion. The stimuli consist of sparse random-dot arrays, in which dots remain in place. Changes of luminance or color of the dots at leading and trailing edges of an apparently moving region are integrated over space and time to produce the perception of well-defined contours, shapes, and color. We test how Vernier acuity of apparent motion-defined illusory bars depends on speed, density, and stimulus configurations. We found that higher speed of apparent motion reduces the Vernier acuity thresholds. These thresholds also decrease with increasing density of dots, whose luminance changes provide the apparent motion signal required for the perception of illusory contours. In subsequent experiments, we showed that luminance-defined flankers could seamlessly integrate with and improve the perception of apparent motion-defined contours, reducing their Vernier thresholds.

Color↗
PubMed2006

Uveal melanocytes do not respond to or express receptors for alpha-melanocyte-stimulating hormone.

PURPOSE: Whereas cutaneous pigmentation increases after exposure to ultraviolet (UV) irradiation, ocular pigmentation does not. This study was designed to examine the evidence that alpha-melanocyte-stimulating hormone (alpha-MSH), which is thought to be the mediator of UV response in the skin, has any role to play in uveal melanocytes. METHODS: Human uveal melanocytes derived from the choroid and the iris were cultivated by using eyes harvested from adult cadaveric donors and were assessed by Northern blot analysis for growth and melanogenic response to alpha-MSH and expression of the receptor for alpha-MSH (MC1-R). In addition, expression of alpha-MSH was evaluated in ocular tissue by immunocytochemistry. RESULTS: Uveal melanocytes, unlike cutaneous melanocytes in vitro, exhibited no stimulation of proliferation in response to alpha-MSH at dosages ranging from 0.1 to 100 muM. In addition, tyrosine hydroxylase, DOPA oxidase, and protein levels for tyrosinase, TRP-1, and TRP-2 were not influenced by alpha-MSH. Associated with the lack of alpha-MSH response in cultured uveal melanocytes was the absence of expression of the receptor for alpha-MSH (MC1-R), as assessed by Northern blot analysis. Also in contrast to the skin, pigmented ocular tissue lacked expression of the alpha-MSH ligand, as assessed by immunocytochemistry. CONCLUSIONS: In conclusion, ocular pigmentation does not appear to be regulated by melanocyte stimulating hormone.

Blotting, Northern↗
PubMed2003

Peak pressures: crossover study of timolol and latanoprost.

PURPOSE: To compare the diurnal efficacy and action on peak intraocular pressures (IOP) of 0.005% latanoprost and 0.5% timolol as primary therapy in 60 eyes having dark brown irides with primary open angle glaucoma (POAG). METHODS: A prospective, comparative, observer-masked, crossover, interventional trial including the mean of both eyes of 30 patients with POAG who were randomly started on either latanoprost once daily or timolol twice daily. Three months after treatment with one drug, the second drug was substituted. A masked observer carried out diurnal assessments of IOP before the start of therapy and at 3 and 7 months. The fourth month was the washout period for the first drug. RESULTS: The average baseline IOP was 23.36 +/- 2.14 mm Hg, which was reduced by 8.8 +/- 2.2 mmHg with latanoprost (p < 0.01) and by 6.75 +/- 1.9 mm Hg with timolol (p = 0.01). The reduction was greater for latanoprost (p < 0.005). The average peak IOP at baseline was 27.6 +/- 2.22 mmHg. The effective fall in IOP at the time of new peaks in subsequent diurnal recordings of IOP compared to the baseline diurnal curve was 8.9 mm Hg with latanoprost (p < 0.005) and 5.77 mm Hg with timolol (p < 0.01). This difference in IOP reduction between the two drugs was statistically significant (p < 0.01). Latanoprost had a lower efficacy in peak IOP reduction in eyes with evening peak of IOP than in those with morning peak (p < 0.005). The efficacy of timolol was lower overall compared to latanoprost, but was similar in all circadian rhythms. The shift in timing of IOP peak was greater with latanoprost compared to timolol (4.34 hours vs -0.72 hours, p < .01). A total of 90% of patients on latanoprost and 33.3% on timolol achieved a reduction of > 30% in baseline mean IOP. The average of the trough IOP recorded in each of the individual baseline IOP curves was 19.05 +/- 2.05 mm Hg. CONCLUSIONS: Greater mean and peak IOP reduction was achieved with latanoprost compared to timolol. Dampening of the circadian rhythm was better with latanoprost. Latanoprost appears to be more effective than timolol at all points in time with greater efficacy in eyes with morning peaks compared to evening peaks.

Administration, Topical↗
PubMedDate not supplied

Factors predisposing to postoperative intraocular inflammation.

This prospective study of 123 patients undergoing cataract extraction determined the preoperative and surgical factors predisposing to an exaggerated postoperative inflammatory response. It is important to identify the patients at increased risk of complications requiring additional prophylaxis or more intensive postoperative care, particularly when selecting patients for day case surgery. Previous intraocular inflammation or surgery was the factor most strongly associated with marked inflammation on the first postoperative day (p < 0.01, compared to uncomplicated patients). As a result, patients stayed in hospital an average of one day longer (p < 0.001) and required significantly more steroid drops (p < 0.001). Other factors of significance, but reducing importance were: difficult surgery, non-caucasian race and brown irides. Amongst uncomplicated patients, the difficulty of surgery was most significantly related to a high inflammation score (p < 0.01). Non-caucasian patients stayed in hospital significantly longer than their caucasian counterparts (p < 0.05), and required more steroid drops (p < 0.001). Of caucasian patients, those with brown irides were inpatients for significantly longer than those with blue or hazel (p < 0.05). No other factors studied significantly altered postoperative inflammation: neither the presence of diabetes, nor the technique of cataract extraction.

Aged↗
PubMed2006

Anthropometric measures in relation to basal cell carcinoma: a longitudinal study.

BACKGROUND: The relationship between anthropometric indices and risk of basal cell carcinoma (BCC) is largely unknown. We aimed to examine the association between anthropometric measures and development of BCC and to demonstrate whether adherence to World Health Organisation guidelines for body mass index, waist circumference, and waist/hip ratio was associated with risk of BCC, independent of sun exposure. METHODS: Study participants were participants in a community-based skin cancer prevention trial in Nambour, a town in southeast Queensland (latitude 26 degrees S). In 1992, height, weight, and waist and hip circumferences were measured for all 1621 participants and weight was remeasured at the end of the trial in 1996. Prevalence proportion ratios were calculated using a log-binomial model to estimate the risk of BCC prior to or prevalent in 1992, while Poisson regression with robust error variances was used to estimate the relative risk of BCC during the follow-up period. RESULTS: At baseline, 94 participants had a current BCC, and 202 had a history of BCC. During the 5-year follow-up period, 179 participants developed one or more new BCCs. We found no significant association between any of the anthropometric measures or indices and risk of BCC after controlling for potential confounding factors including sun exposure. There was a suggestion that short-term weight gain may increase the risk of developing BCC for women only. CONCLUSION: Adherence to World Health Organisation guidelines for body mass index, waist circumference and waist/hip ratio is not significantly associated with occurrence of basal cell carcinomas of the skin.

Adult↗
PubMed1996

Position-effect variegation in Drosophila depends on dose of the gene encoding the E2F transcriptional activator and cell cycle regulator.

A dominant mutation due to the insertion of a P-element at 93E on the third chromosome of Drosophila melanogaster enhances position-effect variegation. The corresponding gene was cloned by transposon tagging and the sequence of the transcript revealed that it corresponds to the gene encoding the transcriptional activator and cell cycle regulator dE2F. The transposon-tagged allele is homozygous viable, and the insertion of the transposon in an intron correlates with a strong reduction in the amount of transcript. A homozygous lethal null allele was found to behave as a strong enhancer when heterozygous. Overexpression of the gene in transgenic flies has the opposite effect of suppressing variegation. A link is established here, and discussed, between the dose of a transcriptional activator, which controls the cell cycle, and epigenetic silencing of chromosomal domains in Drosophila.

Amino Acid Sequence↗