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At least 109 records · Page 6Linked to original sources

Identification of a Keratin 4 mutation in a chemically induced mouse mutant that models white sponge nevus.

With the goal of increasing the number of genetic entry points for studying physiologic processes and human disease, large-scale, systematic, chemical mutagenesis projects in mice have been initiated in several different centers. We have been studying mouse mutants that exhibit dominantly inherited defects in either skin and/or hair color. Here, we describe a bright coat color mutant, Bright coat color 1 (Bcc1), which develops light-colored hair at 4 weeks of age, and when homozygous exhibits oral leukoplakia and blistering, and growth retardation. We identified a missense mutation in mutant animals that predicts an N154S amino-acid substitution in the 1A domain of Keratin 4 (encoded by the Krt2-4 gene), a region known to be mutated in human patients with white sponge nevus (WSN). Bcc1 recapitulates the gross pathologic, histologic, and genetic aspects of the human disorder, WSN.

Animals↗

Assessing the potential of a "color effect" for hair analysis of 11-nor-9-carboxy-delta(9)-tetrahydrocannabinol: analysis of a large sample of hair specimens.

It has been hypothesized that hair color may play a role in the concentration of various drugs of abuse in hair. Several studies have shown that melanin in hair appears to play a binding role for at least some commonly abused drugs. However, these studies have been limited by a number of factors when assessing the clinical significance of a hypothesized melanin or color effect. This study evaluates the possible effect of hair color on the concentration of 11-nor-9-carboxy-Delta(9)-tetrahydrocannabinol (c-THC) in human hair. The analysis is based on 3886 positive c-THC hair specimens drawn from a universe of approximately 80000 specimens of scalp hair harvested from the posterior vertex of the head. Analysis of variance of color categorization by c-THC concentration shows that c-THC concentration does not have a significant association with hair color (Hair Color F = 1.148, p =.332) and therefore does not have a demonstrable "color effect".

Dronabinol↗

Risk factors for epithelial erosions in laser in situ keratomileusis.

PURPOSE: To determine the risk factors for an epithelial defect during laser in situ keratomileusis (LASIK). SETTING: LASIK Vision, Toronto, Ontario, Canada. METHODS: In this prospective cohort study, 926 patients (1852 eyes) presenting for LASIK over a 6-month period were evaluated for age, sex, Fitzpatrick Skin Type (FST), eye color, hair color at 3 years of age, facial skin wrinkling, ethnicity (Lancer Ethnicity Scale [LES]), keratometry, Schirmer I reading, corneal thickness, and preexisting signs of corneal epithelial dystrophy. In all patients, LASIK was performed using the Technolas 217 laser (Bausch & Lomb), the Hansatome(R) microkeratome (Bausch & Lomb), and the same nomogram settings. RESULTS: Fourteen percent of patients had significant epithelial fragility. In patients with FST I or II or LES 1 or 2, the relative risk of an epithelial defect was 10 times greater than in other patients; in those older than 40 years, it was 6 times greater than in other patients; in those with lighter hair or eye color, it was 2 to 3 times greater than in patients with darker hair or eyes. There was no significant difference in pachymetry, vertical or horizontal keratometry, or Schirmer readings between eyes with epithelial defects and eyes without. CONCLUSIONS: The risk of epithelial erosions during LASIK strongly correlated with patients' skin type and age.

Adult↗

Inbreeding studies in Brasilian schoolchildren.

We present results of comparisons between consanguineous and control couples and their children in Southern Brasil. Multiple regression, t-test and chi 2 analyses were applied to the data. The following variables were investigated; Parents: structure of first cousin marriages, latitude and longitude of birthplaces, cohabitation time, rurality, marriage age, occupation, number of liveborn children, and frequency of twinning. Schoolchildren: clinical data as classified into 24 discontinuous traits, each one subdivided into two categories (number and severity), and seven continuous traits (weight, height, pulse rate, respiratory rate, systolic pressure, diastolic pressure, and temperature); nutrition indices and biotype; family names; intelligence tests and school performance; birth order, age, hair color, hair type, eye color, and skin color; twinning in the sibship, and infant mortality among sibs of the propositi. Our study showed a) nonrandomness of consanguineous marriages as detected on structural, racial, geographical, and temporal levels; b) a heavy mutational load of about 1.5 lethons acting on infant mortality; c) no inbreeding effect on morbidity in general (with a possible exception of "ear morbidity", including hearing deficit); d) a modest inbreeding depression on height (a decrease of 2 cm with an increase of 10% of inbreeding); 3) a suggestion of inbreeding depression on "intelligence".

Brazil↗

[Genotypic and phenotypic markers in patients with chronic obstructive bronchitis].

The study included examination of 120 patients with chronic obstructive bronchitis (COB) and 70 healthy people. The following genotypic and phenotypic markers were evaluated: blood group, Rhesus factor, earwax type, constitution, height, iris color, hair color, signs of functional asymmetry and some minimal signs of embryogenesis disturbances. The relative risk of the disease development was counted for each parameter. The study found the highest COB morbidity in short normosthenics people with short neck, wet earwax type, nasal septum deviation and B (III) blood group. Such markers as light brown hair and dry earwax type were shown to be associated with COB-protective activity. The signs discussed in the article may be used to determine predisposition to COB.

Adolescent↗

Is a "color effect" demonstrated for hair analysis of carbamazepine?

Psillakis et al. have reported on the concentration of carbamazepine recovered from hair samples collected from patients receiving this anti-seizure medication under medical supervision and determined that their was a high correlation between dose and quantitation of recovered analyte. The analyte was identified by two techniques, FPIA (Abbott TDx) and HPLC and the correlation was high for both procedures. In the literature on hair analysis some have suggested that analyte concentration in hair is critically dependent on hair color. In reporting their data Psillakis et al. reported the hair color of each patient but made no attempt to analyze their results in relation to color. This article performs a secondary analysis of the Psillakis et al. data in order to determine whether there is a hair color effect discernible in the recovery of carbamazepine from hair. Analysis of this data set for both the FPIA and HPLC by one-way analysis of variance fails to identify a color effect at p = .05. Weighting the data for per-patient dosage values fails to discern a color effect. Examination of all possible two-color comparisons also fails to identify a statistically significant effect for any subset of combinations. These data suggest that carbamazepine does not exhibit a color effect when using either FPIA or HPLC assay methods.

Adolescent↗

Dysplastic nevi as risk markers of sporadic (nonfamilial) melanoma. A case-control study.

The melanoma risk associated with dysplastic nevi outside the context of familial melanoma was studied by the case-control method. One hundred five newly diagnosed incident melanoma cases with negative family histories for familial melanoma and 181 controls (frequency matched for race, age, and sex) were studied by personal interview and cutaneous examination. The prevalence of dysplastic nevi was 41 (39%) of 105 in the cases and 13 (7%) of 181 in the controls. The odds ratio for dysplastic nevi by multiple logistic regression analysis simultaneously correcting for age, sex, eye color, hair color, actinic damage, freckles, and total number of nondysplastic nevi was 6.8 (95% confidence interval, 2.7, 16.9). This study supports the significance of dysplastic nevi as markers of increased risk for nonfamilial melanoma.

Case-Control Studies↗

The association of solar ultraviolet and skin melanoma incidence among caucasians in the United States.

Using recent data from cancer incidence surveys and measures of UVB exposure levels at seven geographic locations within the United States, we estimate the dose-response relation between UVB and skin melanoma incidence. Mathematical models used information from general population interview studies conducted in these locations to adjust for potentially confounding factors such as age, skin color, ancestry, eye color, hair color, sunburn sensitivity, prevalence of moles, freckles, and hours spent outdoors, use of sunscreen/lotion, and other variables. The effect of geographic UVB exposure on incidence was found to be statistically significant (p less than 0.01) after adjusting for each variable and certain combinations of these variables. We found that incidence rates for those skin melanomas arising in the face, head, neck, or upper extremities (i.e, the most exposed sites) were more sensitive to UVB increases than the incidence rates for those lesions occurring in the ordinarily less exposed sites of the trunk and lower extremities.

Female↗

Infants' perception of similarity between live people and their photographs.

5-month-old infants who had been habituated to a live face showed no change in fixation time when presented with an immediately following photographic slide of that same face, while they showed an increase in fixation time (dishabituation) to a photographic slide of a novel face of different sex, hair color, and hair style. The similarity in responses to the live person and his photograph indictaes that some identification of people in photographs is possible even in the absence of extended prior developmental experience with pictures. A second experiment found that 5-month-old Ss exhibited the same amount of looking when a live face was followed either by its own photograph or by a photograph of a novel person of like sex, hair color, and hair style. Apparently, these Ss used only rather gross physiognomic features to perceive a similarity between a live person and that person's photograph.

Discrimination, Psychological↗

Use of image analysis techniques for objective quantification of the efficacy of different hair removal methods.

In the field of consumer-used cosmetics for hair removal and hair growth reduction, there is a need for improved quantitative methods to enable the evaluation of efficacy and claim support. Optimized study designs and investigated endpoints are lacking to compare the efficacy of standard methods, like shaving or plucking, with new methods and products, such as depilating instruments or hair-growth-reducing cosmetics. Non-invasive image analysis, using a high-performance microscope combined with an optimized image analysis tool, was investigated to assess hair growth. In one step, high-resolution macrophotographs of the legs of female volunteers after shaving and plucking with cold wax were compared to observe short-term hair regrowth. In a second step, images obtained after plucking with cold wax were taken over a long-term period to assess the time, after which depilated hairs reappeared on the skin surface. Using image analysis, parameters like hair length, hair width, and hair projection area were investigated. The projection area was found to be the parameter most independent of possible image artifacts such as irregularities in skin or low contrast due to hair color. Therefore, the hair projection area was the most appropriate parameter to determine the time of hair regrowth. This point of time is suitable to assess the efficacy of different hair removal methods or hair growth reduction treatments by comparing the endpoint after use of the hair removal method to be investigated to the endpoint after simple shaving. The closeness of hair removal and visible signs of skin irritation can be assessed as additional quantitative parameters from the same images. Discomfort and pain rating by the volunteers complete the set of parameters, which are required to benchmark a new hair removal method or hair-growth-reduction treatment. Image analysis combined with high-resolution imaging techniques is a powerful tool to objectively assess parameters like hair length, hair width, and projection area. To achieve reliable data and to reduce well known image-analysis artifacts, it was important to optimize the technical equipment for use on human skin and to improve image analysis by adaptation of the image-processing procedure to the different skin characteristics of individuals, like skin color, hair color, and skin structure.

Adult↗

Fixed-distance latent class models for the analysis of sets of two-way contingency tables.

This paper develops and describes the application of modified latent class models for analyzing sets of two-way contingency tables. The proposed fixed-distance models differ from traditional latent class models in that the assumption of local stochastic independence is superseded by allowing interactions of the manifest variables within each class, which can be represented by a single association parameter. As an example, two data sets on eye color by hair color [collected in Caithness (N1 = 5,387) and Aberdeen (N2 = 22,361)] and fixed-distance models with up to six classes (three classes per data set) are considered, finally leading to satisfactory fit and rather simple interpretation.

Child↗

Coloring the hair.

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Coloring Agents↗

Development and reliability of a brief skin cancer risk assessment tool.

This study aimed to develop and pilot test a brief skin cancer risk assessment tool (BRAT), a self-administered instrument that can be reliably used to assess skin cancer risk. To develop the BRAT, we critically reviewed published literature on risk factors; formulated a draft questionnaire; pilot tested the questionnaire; and retested 1 month later. The BRAT items address the key risk factors for melanoma and other keratinocyte skin cancers: ethnicity, personal and family history of skin cancer, mole count, freckles, childhood residence, sunburn history, and sun sensitivity factors (skin color, natural hair color, ease of sunburning and tanning). One hundred sixty-five persons completed the initial BRAT pilot study, and 52 additional people at moderate- or high-risk completed a second BRAT pilot study. Results were as follows: using a dichotomous risk measure, about 90% of subjects would be correctly classified at baseline and follow-up. Weighted kappa for the total BRAT score (0.41-0.68) and for individual items (0.57-0.99) were fair to good, as were correlation coefficients. The BRAT has acceptable to good reproducibility. Reliability statistics compared favorably with those reported in the literature for similar measures.

Adult↗

Risk factors of squamous cell carcinoma of the skin. A case-control study in the Montreal region.

A matched case-control study was undertaken to assess the relative risk associated with known and suspected risk factors of squamous cell carcinoma of the skin among patients in the Montreal region. Three hundred eleven cases histologically diagnosed in 1977 and 1978 in 12 hospitals and meeting strict definition criteria were identified. With the exception of six cases, two controls were matched to each case for sex, age, and hospital of diagnosis. A logistic regression analysis was done. The known host risk factors (eye and hair color, complexion, descent) and nonoccupational sunlight exposure were found to be operative in the Montreal region. After adjusting for these factors, occupational sunlight exposure appeared to be a risk factor. An association was then observed between the risk of squamous cell carcinoma of the skin and tobacco smoking and the use of a sunlamp. Relative risks associated with the above-mentioned factors were estimated.

Age Factors↗

Pigmentary traits, nevi and skin phototypes in a youth population of Central Italy.

Five thousand eight hundred and thirty-seven healthy young men, aged 18-19, from two distinct regions of Central Italy, Abruzzo and Marche, have been investigated during the military medical examination to evaluate pigmentary traits and skin phototypes. They were examined over the entire body except the scalp and ano-genital area for pigmented lesions, which included common acquired melanocytic nevi (MN), clinically atypical nevi and solar lentigines. Eye and hair color were also recorded. Information was gathered by self-questionnaire, personal interview and clinical skin examination performed by two independent dermatologists. For sunlight susceptibility and sun exposure, each subject was classified from I to IV skin phototype according to the classification of sun-reactive skin types as proposed by Fitzpatrick. Almost half of the entire population (44.5%) had affirmed that they tanned easily and rarely burned (phototype IV), 10.3% had skin phototype I or II, 11.2% had more than 40 common MN, and 37.2% had atypical nevi with a diameter > or = 5 mm. The common MN and atypical nevi count had a significant association with skin phototype. Subjects with phototype I or II, and solar lentigo had significantly higher nevus counts than individuals without these characteristics.

Adolescent↗