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Sunlight Exposure (sunlight + exposure)

Distribution by Scientific Domains

Medical Sciences	70%
Life Sciences	20%

Distribution within Medical Sciences

Dermatology	47%
Oncology & Radiotherapy	14%

Selected Abstracts

Effect of sunlight exposure and aging on skin surface lipids and urate

EXPERIMENTAL DERMATOLOGY, Issue 2003
Nobumasa Hayashi
Abstract Free fatty acids (FFA), squalene, squalene hydroperoxide, and uric acid in the methanol extracts from human skin surface were measured. Levels of FFA and squalene were significantly lower in the older (83.7 ± 9.4 years) than in the younger (22.2 ± 3.9 years) group. FFA are mostly saturated, and linoleic acid is an exclusive polyunsaturated fatty acid. The composition of linoleic acid decreased in the older group by 40%, suggesting age-dependent loss of oxidatively vulnerable polyunsaturated fatty acid. Even monounsaturated acids such as palmitoleic and oleic acids decreased significantly in the older group. This could be interesting because 2-nonenal is the oxidation product of palmitoleic acid and has been identified as the major aged body odor component. Sunlight exposure for 1.5 h did not change levels of FFA and squalene, or FFA composition. However, squalene hydroperoxide increased by 60-fold, as reported previously, suggesting that hydroperoxide is produced by singlet oxygen. Uric acid increased by two-fold, which may be the adaptive response against photo-oxidative stress because uric acid is a good scavenger of singlet oxygen and oxygen radicals. [source]

Effects of sunlight exposure and log size on pine engraver (Coleoptera: Curculionidae) reproduction in ponderosa pine slash in Northern Arizona, U.S.A.

AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2009
Christopher J. Hayes
Abstract 1,Abiotic conditions within logs can affect pine engraver Ips pini (Say) reproductive success, and slash management techniques have been developed that exploit these relationships to reduce brood production. In the present study, we investigated the affect of sunlight exposure on phloem temperature and moisture in logs of two diameters and the subsequent effects on pine engraver reproduction. 2,Logs, 30 cm in length, with diameters of 10 and 15 cm, were cut, left in the field for natural colonization by I pini, and then placed in an open meadow and under shade cloth, providing 27% and 66% shade, until offspring beetles had left the logs. Phloem temperature and moisture were recorded over the duration of the experiment and, at the end of the field experiment, logs were dissected and galleries were measured to gauge beetle reproductive success. 3,As sunlight exposure increased, phloem temperatures increased and potentially lethal temperatures were often reached in the high-sunlight exposure but seldom in the low-sunlight. Smaller diameter logs had drier phloem than larger diameter logs. All logs dried with time but sunlight level did not affect desiccation rates. Ips pini preferred attacking larger logs and the bottom side of logs. Sunlight exposure had a significant effect on net reproductive success in smaller diameter logs, with very little net reproductive success in high-sunlight exposed logs, and the highest reproductive success was found in small diameter logs in the low-sunlight treatments. 4,Management implications of these results are discussed. [source]

Serum levels of vitamin D, sunlight exposure, and knee cartilage loss in older adults: The Tasmanian older adult cohort study

ARTHRITIS & RHEUMATISM, Issue 5 2009
Changhai Ding
Objective To determine the associations between serum levels of vitamin D, sunlight exposure, and knee cartilage loss cross-sectionally and longitudinally in older adults. Methods A total of 880 randomly selected subjects (mean age 61 years [range 51,79 years], 50% women) were studied at baseline, and 353 of these subjects were studied 2.9 years later. Serum levels of 25-hydroxyvitamin D (25[OH]D) were assessed by radioimmunoassay, and sunlight exposure was assessed by questionnaire. T1-weighted fat-suppressed magnetic resonance imaging (MRI) of the right knee was performed to determine knee cartilage volume and defects. Knee radiographic osteoarthritis (OA) and knee pain were also assessed. Results The mean 25(OH)D serum level was 52.8 nmoles/liter at baseline (range 13,119 nmoles/liter). Winter sunlight exposure and serum 25(OH)D level were both positively associated with medial and lateral tibial cartilage volume, and a serum 25(OH)D level <50 nmoles/liter was associated with increased medial tibiofemoral joint space narrowing (all P < 0.05). Longitudinally, baseline serum 25(OH)D level predicted change in both medial and lateral tibial cartilage volume (, = +0.04% per annum per nmole/liter for both; P < 0.05), and change in serum 25(OH)D level was positively associated with change in medial tibial cartilage volume. These associations were consistent in subjects with radiographic OA and knee pain and/or in women, but not in men or in subjects without radiographic OA or knee pain. Conclusion Sunlight exposure and serum 25(OH)D levels are both associated with decreased knee cartilage loss (assessed by radiograph or MRI). This is best observed using the whole range of 25(OH)D levels rather than predefined cut points and implies that achieving vitamin D sufficiency may prevent and/or retard cartilage loss in knee OA. [source]

Effect of sunlight exposure and aging on skin surface lipids and urate

Carbaryl exposure and incident cancer in the Agricultural Health Study

INTERNATIONAL JOURNAL OF CANCER, Issue 8 2007
Rajeev Mahajan
Abstract Carbaryl is a carbamate insecticide with a broad spectrum of uses in agricultural, commercial and household settings. It has previously been linked with non-Hodgkin lymphoma (NHL) but studies of cancer risk in humans are limited. We examined occupational carbaryl use and risk of all cancers in the Agricultural Health Study, a prospective study of a cohort of pesticide applicators in North Carolina and Iowa. This analysis included 21,416 subjects (1,291 cases) enrolled from 1993,1997 and followed for cancer incidence through 2003. Pesticide exposure and other data were collected using self-administered questionnaires. Poisson regression was used to calculate rate ratios (RRs) and 95% confidence intervals (CIs) while controlling for potential confounders. Carbaryl was not associated with cancer risk overall. Relative to subjects who never used carbaryl, melanoma risk was elevated with >175 lifetime exposure-days (RR = 4.11; 95%CI, 1.33,12.75; p -trend = 0.07), >10 years of use (RR = 3.19; 95%CI, 1.28,7.92; p -trend = 0.04), or ,10 days of use per year (RR = 5.50; 95%CI, 2.19,13.84; p -trend < 0.001). Risk remained after adjusting for sunlight exposure. Although not significant, there appeared to be a trend of decreasing prostate cancer risk with increasing level of exposure. A small increase in NHL risk was observed using some, but not all, exposure measures. No associations were observed with other examined cancer sites. Because the observed results were not hypothesized a priori and because of limited study of their biological plausibility, they should be interpreted with caution. © 2007 Wiley-Liss, Inc. [source]

Cancer risk perceptions in an urban Mediterranean population

INTERNATIONAL JOURNAL OF CANCER, Issue 1 2005
Montse García
Abstract The objective of our study was to analyze the perceived (belief) or adopted (behavior) measures to reduce cancer risk in a Spanish population. We used cross-sectional data from the Cornella Health Interview Survey Follow-up Study (CHIS.FU). We analyzed 1,438 subjects who in 2002 answered questions about risk perceptions on cancer and related behavior (668 males and 770 females). The benefits of avoiding cigarette smoking (95.8%), sunlight exposure (94.9%) and alcohol (81.0%) were widely recognized. On the other hand, electromagnetic fields (92.1%), food coloring and other food additives (78.4%) or pesticides (69.4%), whose role in cancer occurrence, if any, remain unproven, were clearly considered as cancer risk factors in this population. Compared to men, women more frequently reported healthy behaviors, and the role of exogenous factors (i.e., environmental risk factors) were widely popular. There was a socioeconomic gradient on cancer risk perception with respect to several lifestyle or dietary factors. Individuals with higher educational level scored lower in several risk factors than those with primary or less than primary school education. Smokers reported adopting fewer healthy behaviors than former or never smokers. How people perceive health issues and risk or make choices about their own behavior does not always follow a predictable or rational pattern. © 2005 Wiley-Liss, Inc. [source]

Characteristics of skin aging in Korean men and women

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2005
J. H. Chung
Introduction Korea is located between Japan and Mainland China. The people of these three countries have similar appearances and it is difficult to differentiate between them. Although the population of Asia is more than half of the total population of the Earth, the inherent characteristics of Asian skin have not been well investigated. Commercial markets for cosmetics and drugs for photoaged skin are rapidly expanding in many Asian countries. Therefore, many investigators in the field of dermatology and cosmetology have become interested in brown Asian skin. Clinical characteristics of skin aging and photoaging in Asians Skin aging can be divided into two basic processes: intrinsic aging and photoaging [1]. Intrinsic aging is characterized by smooth, dry, pale, and finely wrinkled skin, whereas photoaging, which indicates premature skin aging in chronically photodamaged skin, is characterized by severe wrinkling and irregular pigmentation. The pattern of wrinkling in Asians seems to differ from that in Caucasians. Asians have coarser, thicker and deep wrinkles, particularly in the forehead, perioral and Crow's foot areas. In contrast, Caucasians usually have relatively fine cheek and Crow's foot wrinkles. The reasons for these differences are not known and need further investigation. There are racial, ethnic and genetic differences, and differences of skin structure and function, between the brown skin of Asians and the white skin of Caucasians. As Asian skin is more pigmented, acute and chronic cutaneous responses to UV irradiation differ from those in white skin. Many people believe, based on clinical impressions, that the main process of photoaging in Asians involves pigmentary changes, rather than wrinkling. However, no study has been performed to confirm this belief. Risk factors for skin wrinkles and their relative risks in Korean skin [2] Various factors such as age, sun-exposure, and smoking are known to be important risk factors for wrinkles. However, the relative risks of each factor on wrinkles in the brown skin of Asians have not been investigated, and they could differ from those in Caucasians. An evaluation system for skin wrinkling is necessary for Asian skin [3]. Thus, we developed an eight-point photographic scale for assessing wrinkles in both Korean genders [2]. This scale can probably be applied to the populations of other Asian countries, at least to the Japanese and Chinese. The pattern of wrinkles in both genders appears to be similar. Age Age is an important risk factor for wrinkling in Asians, as in Caucasians. Korean subjects in their 60s showed a 12-fold increased risk of wrinkling, while subjects in their 70s have a 56-fold increased risk compared with young age group. UV light It is well known that the UV component in sunlight can cause and accelerate photoaging. The pigmented skin of Asian may better protect skin from acute and chronic UV damage. However, we found a strong association between sun-exposure and the development of wrinkling in Koreans. It was found that sun exposure of more than 5 h per day was associated with a 4.8-fold increased risk in wrinkling versus less than 2 h of sun-exposure in Koreans. Estrogen deficiency Korean females have more wrinkles than men, after controlling for age, sun exposure, and smoking, it was found that they have a 3.6-fold increased risk of developing wrinkles than their male counterparts [2]. It has also been reported, that the relative risk for wrinkling in women is higher than in men as for in white Caucasians [4]. The reason why women show more wrinkles remains to be determined. It is possible that a reduction in skin collagen because of estrogen deficiency in postmenopausal woman may aggravate wrinkling severity. Korean women with more than 10 years since menopause showed a 3.9-fold higher risk of wrinkling than the women 5 years of beyond menopause [5]. We demonstrated that women with a history of HRT have a significantly lower risk, more specifically, one fifth of the risk of facial wrinkling relative to those who had no history of HRT. Interestingly, we found that wrinkle severity significantly increased with an increasing number of full term pregnancies. The relative risk for severe wrinkling is increased by approximately 1.8-fold per full term pregnancy. Smoking It is known that smoking causes skin wrinkling in Caucasians, and that it plays no role in Blacks [6, 7]. Koreans with have a smoking history of more than 30 pack years showed a more than 2.8-fold increased risk of wrinkles [2]. The relative risks of wrinkles associated with a 30,50 pack-years history of smoking were 2.8- and 5.5-fold, respectively. Dyspigmentation in Asian skin To follow pigmentary changes, six photographic standards for both genders were developed for Korean skin, to produce a 6-point scale [2, 8]. Hyperpigmented spots, mostly lentigines, were prominent among women, while seborrheic keratosis tended to be more prominent in men. Seborrheic keratosis in Korean men Seborrheic keratoses (SKs) are benign cutaneous tumors. They have diverse clinical and histopathological appearances and are very common in the elderly (over 50 years old). The etiology of SKs is not well understood, although patients with a great number of lesionsshow a familial trait with an autosomal dominant pattern, and human papilloma virus has been suggested as possible cause because of verrucous appearance of the lesions. Exposure to sunlight has been suggested to be a risk factor for SKs. However, there is still some debate in terms of the role of sunlight. Recently, we have investigated the clinical characteristics of SKs and relationship between SKs and sunlight exposure in Korean males [9]. The prevalence of SKs in Koreans increases with age; it rose from 78.9% at 40 years, to 93.9% at 50 years and 98.7% in those over 60 years. Exposed areas, i.e. the face, neck and dorsum of the hands, demonstrate a significant increase in the prevalence of SKs by decade, whereas partly exposed areas, although SKs tended to increase in prevalence with age, this trend was not significant. When the estimated body surface area (BSA) is taken into account, the number of SKs on both the face and dorsum of the hands (0.51 ± 0.08 per 1% BSA) was over-represented compared with the trunk. SKs were also concentrated on the neck (0.38 ± 0.07 per 1% BSA) and in the V-area (0.47 ± 0.09 per 1% BSA). Outer forearms also showed 3-fold more SKs per unit area than neighboring arms and inner forearms, which are classified as partly exposed area (0.09 ± 0.02, 0.03 ± 0.01, respectively). The total area covered by SKs on exposed area also became significantly larger with aging than on intermittently exposed areas. These results indicate that exposure to sunlight might be related to SK growth. Our results indicated that excessive sun exposure is an independent risk factor of SKs. After controlling for age, smoking, and skin type, subjects with a sun exposure history of more than 6 hours per day showed a 2.28-fold increased risk of having severe SKs (n , 6) compared with those exposed for less that 3 h per day. These findings indicated that sun-exposure may play an important role in SK development. In summary, SKs are very common in Korean males and represent one of the major pigmentary problems. SKs concentrate on exposed skin, especially on the face and dorsum of the hands. Both age and lifetime cumulative sunlight exposure are important contributing factors and may work in a synergistic manner. Conclusion Many people tend to believe that wrinkles are not a prominent feature of Asian photoaged skin, and that dyspigmentation is a major manifestation in Asian skin. Contrary to this impression, wrinkling is also a major problem in the photoaged skin of Asians, and Korean people showing severe pigmentary changes usually tend to have severe wrinkles. In conclusion, the wrinkling patterns and pigmentary changes of photoaged skin in East Asians differ from those of Caucasians, and the relative risks of aggravating factors may be different from those of Caucasian skin. References 1.,Gilchrest, B.A. Skin aging and photoaging: an overview. J. Am. Acad. Dermatol. 21, 610,613 (1989). 2.,Chung, J.H. et al. Cutaneous photodamage in Koreans: influence of sex, sun exposure, smoking, and skin color. Arch. Dermatol. 137, 1043,1051 (2001). 3.,Griffiths, C.E. et al. A photonumeric scale for the assessment of cutaneous photodamage. Arch. Dermatol. 128, 347,351 (1992). 4.,Ernster, V.L. et al. Facial wrinkling in men and women, by smoking status. Am. J. Public Health. 85, 78,82 (1995). 5.,Youn, C.S. et al. Effect of pregnancy and menopause on facial wrinkling in women. Acta Derm. Venereol. 83, 419,424 (2003). 6.,Kadunce, D.P. et al. Cigarette smoking: risk factor for premature facial wrinkling. Ann. Intern. Med. 114, 840,844 (1991). 7.,Allen, H.B., Johnson, B.L. and Diamond, S.M. Smoker's wrinkles? JAMA. 225, 1067,1069 (1973). 8.,Chung, J.H. Photoaging in Asians. Photodermatol. Photoimmunol. Photomed. 19, 109,121 (2003). 9.,Kwon, O.S. et al. Seborrheic keratosis in the Korean males: causative role of sunlight. Photodermatol. Photoimmunol. Photomed. 19, 73,80 (2003). [source]

Photoinduced acute exanthematous pustulosis caused by ciprofloxacin and sunlight exposure

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 10 2009
Keith Allen Knoell MD
No abstract is available for this article. [source]

Photoallergic contact dermatitis caused by ultraviolet filters in different sunscreens

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 2008
Esther J. H. Collaris MD
Over the last decade, a change in the public awareness regarding the possible danger of excessive sunlight exposure has resulted in an increased consumption of sunscreens. These products contain a broad spectrum of putative sensitizers that can cause contact dermatitis and, upon exposure to ultraviolet (UV) irradiation, photocontact dermatitis. Among these sensitizing compounds, UV filters are the most frequent cause of photoallergic reactions. Although rarely observed, we here describe the occurrence of a photoallergic contact dermatitis in a 55-year-old man after the use of two different sunscreens. Photopatch testing showed hypersensitivity reactions of the delayed type against three different chemical UV filters, 4-tert-butyl-4- methoxy-dibenzoylmethane (Parsol 1789), 2-ethylhexyl-p-methoxycinnamate (Parsol MCX), and isoamyl-p-methoxycinnamate (Neoheliopan). [source]

Celecoxib-induced photoallergic drug eruption

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 6 2004
Ayca Cordan Yazici MD
Photoallergic dermatitis is caused by a photosensitizing substance plus sunlight exposure in a sensitized person. If the photosensitizer is delivered internally, it is called a photoallergic drug reaction. Celecoxib is a new generation non-steroidal anti-inflammatory drug and sulfonamide derivative. We report a photoallergic drug eruption associated with the introduction of celecoxib. To our knowledge, this is the first report of photoallergic drug reaction associated with celecoxib. [source]

Photochemical cleavage of a tattoo pigment by UVB radiation or natural sunlight

JOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT, Issue 7 2007
Eva Engel
Summary Background: Millions of people have at least one tattoo. Complex and light absorbing molecules are implanted in the skin. When tattooed skin receives UV radiation or natural sunlight, photochemical cleavage of the pigments may occur. As a first step, we dissolved pigments in a suitable solvent and analyzed them after light irradiation. Methods: The widespread Pigment Red 22 was dissolved in different solvents. The solutions were irradiated with either UVB radiation (up to 8 h) or with natural sunlight (110 days). After irradiation, the solutions were analyzed by means of liquid chromatography and mass spectrometry. Results: A clear cleavage of the pigment was detected in all solvents and the primary decomposition products were identified. In tetrahydrofuran and dioxane, the pigment concentration decreased significantly during UVB irradiation, whereas the pigment was completely destroyed during sunlight exposure. In chloroform and dichloromethane, the pigment concentration decreased slightly during UVB irradiation, whereas the pigment was almost completely destroyed during sunlight exposure. Conclusion: Since chloroform and dichloromethane do not affect the cleavage process, these solvents are optimal for such in vitro experiments. We have shown the cleavage of the tattoo pigment Red 22 when exposed to UVB radiation or natural sunlight. The decomposition products are hazardous showing a potential risk of being toxic or even carcinogenic. At present, a risk assessment is not feasible since the concentration of pigments and their decomposition products in skin are unknown. [source]

Vitamin D and multiple sclerosis

JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2008
Anita Raghuwanshi
Abstract Vitamin D is a principal regulator of calcium homeostasis. However, recent evidence has indicated that vitamin D can have numerous other physiological functions including inhibition of proliferation of a number of malignant cells including breast and prostate cancer cells and protection against certain immune mediated disorders including multiple sclerosis (MS). The geographic incidence of MS indicates an increase in MS with a decrease in sunlight exposure. Since vitamin D is produced in the skin by solar or UV irradiation and high serum levels of 25-hydroxyvitamin D (25(OH)D) have been reported to correlate with a reduced risk of MS, a protective role of vitamin D is suggested. Mechanisms whereby the active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) may act to mediate this protective effect are reviewed. Due to its immunosuppressive actions, it has been suggested that 1,25(OH)2D3 may prevent the induction of MS. J. Cell. Biochem. 105: 338,343, 2008. © 2008 Wiley-Liss, Inc. [source]

Effects of sunlight exposure and log size on pine engraver (Coleoptera: Curculionidae) reproduction in ponderosa pine slash in Northern Arizona, U.S.A.

Bone mass in young adults with Down syndrome

JOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 3 2008
M. Guijarro
Abstract Background Down syndrome (DS) is a frequent cause of intellectual disability. With the increasing life expectancy of these patients, concerns have been raised about the risk of osteoporosis. In fact, several investigators have reported a reduced bone mass in DS. However, the results may be confounded by comorbid diseases, and differences in lifestyle habits and body size. Therefore, we planned to determine anthropometric and lifestyle factors influencing bone mineral density (BMD) in young adults with DS. Methods Thirty-nine patients with DS (mean age 26 years) and 78 controls were studied. Areal BMD was measured by dual x-ray decsitometry (DXA); volumetric BMD at the lumbar spine and femoral neck was estimated with published formulae. Results DS patients had lower areal BMD than controls at all regions (spine, hip and total body). Height and projected bone area were also lower. There were no differences between both groups regarding estimated volumetric BMD at the femoral neck. However, spine volumetric BMD was also lower in DS than controls. In multivariate analysis, DS, male sex, little physical activity and low sunlight exposure were associated with lower spine volumetric BMD; on the other hand, fat mass and sunlight exposure were associated with femoral neck volumetric BMD. Conclusion This study shows that patients with DS had a reduced areal BMD, but it is in part a consequence of the reduced body size, particularly at the femoral neck. Physical activity and sunlight exposure are associated to volumetric BMD and should be stimulated in order to maintain an adequate bone mass in these patients. [source]

Optimization of treatment parameters for Foscan®-PDT of basal cell carcinomas

LASERS IN SURGERY AND MEDICINE, Issue 5 2008
Christian S. Betz MD
Abstract Background and Objective Basal cell carcinomas (BCCs) are the most common form of skin cancers with high and increasing incidence rates. Photodynamic therapy (PDT) with mTHPC (Foscan®) has shown to be a promising treatment alternative with good cosmetic results. The current study was aimed to determine optimal treatment parameters for this indication. Study Design/Materials and Methods mTHPC-PDT was performed in 117 patients with a total of 460 BCCs with diagnosis confirmed by scratch cytology. Treatment parameters were altered as follows: Foscan® dose 0.03,0.15 mg/kg, drug-light interval (DLI) 1,96 hours, total energy density 20,120 J/cm2. Outcomes were assessed 8 weeks post-PDT following WHO guidelines. Results The overall rate of complete remissions (CR) was 96.7% and the cosmetic outcome was very good. In the largest subgroup (n,=,80) where low-dose Foscan® was applied (0.05 mg/kg mTHPC; 48 hours DLI; 50 J/cm2 total energy density), a CR rate of 100% with a high and narrow 95% Confidence Interval of 0.955,1.000 was achieved. Smaller variations of the treatment parameters (i.e., reducing the photosensitizer dose to 0.04 mg/kg or shortening the DLI to 24 hours) yielded similarly good results. Side effects were encountered in 52 out of 133 PDT sessions. They were more common in patients who had received high drug doses (0.06,0.15 mg/kg) and comprised mostly pain and phototoxic reactions. Three patients developed severe sunburns with subsequent scarring at the injection site following bright sunlight exposure 15,19 days after photosensitizer administration. Conclusions The presented data suggest that mTHPC-PDT with the treatment parameters mentioned above seems to be an effective treatment option for BCCs. If sensibly applied, it is well tolerated and provides mostly excellent cosmetic results. Long-term results are yet to be evaluated. Lesers Surg. Med. 40:300,311, 2008. © 2008 Wiley-Liss, Inc. [source]

Enhanced Bactericidal Activity of Modified Titania in Sunlight against Pseudomonas aeruginosa, a Water-Borne Pathogen

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2010
S. Swetha
Photocatalyst-mediated inactivations generate reactive oxygen species and OH radicals, which induce oxidative destruction of membrane integrity, causing damage to membrane phospholipids of gram negative bacteria like Pseudomonas aeruginosa. Nanosized TiO2 was synthesized by gel to crystalline conversion and Zr-doped TiO2 was synthesized by pulverization using appropriate precursor. The doped nanocrystals retained the anatase phase with a marginal increase in crystallite size, averaging at 25 nm. SEM,EDX analysis of the doped sample depicts the substantial growth of grain size with 1.33 atomic weight % of zirconium. The created electron states in the doped sample act as charge carrier traps suppressing recombination which later detraps the same to the surface of the catalyst causing enhanced interfacial charge transfer. Zr-doped TiO2 at the molecular scale exhibits better photocatalytic activity with lower bandgap energy that can respond to visible light. The redshift caused by the dopants in absorption spectra of TiO2 facilitated the nonintrinsic sample to exhibit nearly 2-fold enhancement of photoinactivation in sunlight. Extent of photoinactivation of P. aeruginosa was observed to be complete (100%) within 150 min of sunlight exposure in the presence of modified TiO2. [source]

Mitigating Photosensitivity of Erythropoietic Protoporphyria Patients by an Agonistic Analog of ,-Melanocyte Stimulating Hormone,

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2009
Juergen H. Harms
Erythropoietic protoporphyria (EPP) is a rare hereditary disorder characterized by dermal accumulation of the photosensitizer protoporphyrin IX. Following sunlight exposure, the resulting photosensitivity is manifested first as pain, later as erythema, edema and dermal lesions. Afamelanotide (Nle4 -d-Phe7 -,-MSH), a synthetic analog of ,-melanocyte stimulating hormone and agonist of the melanocortin-1-receptor, promotes melanin synthesis, increasing skin pigmentation. This study examines the efficacy of afamelanotide in preventing symptoms in patients with EPP. A sustained-release subcutaneous implant of 20 mg afamelanotide was administered twice, with a 60-day interval to five EPP patients. Therapeutic efficacy was assessed by a photoprovocation test using standardized white light irradiation, melanin density (MD) determination and daily recording of sunlight exposure and symptoms. From Day 30 to Day 120 tolerance to photoprovocation significantly increased compared with baseline (P = 0.007) and skin MD was significantly higher than that recorded at baseline (P = 0.004). Except for two low-grade pain episodes, patients recorded no phototoxic events past Day 4 of treatment. Tolerance to natural sunlight was up to 24 times longer than prior to therapy. The findings demonstrate beneficial effects of afamelanotide in patients with EPP. Due to the limited number of patients enrolled and the design being an open-label study, confirmation by a large-scale trial is required. [source]

Latitude and Incidence of Ocular Melanoma

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2006
Guo-Pei Yu
We investigated the associations between latitude and the incidence of two different types of ocular melanoma, external ocular melanoma (exposed to sunlight) and internal melanoma (not exposed to sunlight), separately. Using 1992,2002 data from the Surveillance, Epidemiology, and End Results (SEER) Program of National Cancer Institute, we identified 2142 ocular melanoma cases in non-Hispanic whites, and then regressed the incidences of various types of ocular melanomas with latitude. Our analysis indicated that the higher the latitude (away from the equator, the less sun exposure), the lower the risk of external ocular melanoma (eyelid and conjunctival melanomas) among non-Hispanic whites (P for trend = 0.018). The incidence increased 2.48 fold from 47,48° to 20,22°. This trend is very similar to that of skin melanoma. The incidence of internal ocular melanoma (uveal melanoma) increased significantly with increasing latitudes (the less sun exposure, P for trend < 0.0001), it increased 4.91 fold from 20,22° to 47,48°. The latitudinal patterns of ocular melanomas may reflect the dual effects of sunlight exposure, i.e. a mutagenic effect of direct solar radiation on external ocular melanomas and a protective effect for internal uveal melanoma, which is similar to the sun radiation protective effects for various internal malignant tumors that are not exposed to the sunlight. [source]

Radiation Sources Providing Increased UVNUVB Ratios Induce Photoprotection Dependent on the UVA Dose in Hairless Mice

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2006
Vivienne E. Reeve
ABSTRACT In studies involving mice in which doses of UVA (320,400 nm) and UVB (290,320 nm) radiation were administered alone or combined sequentially, we observed a protective effect of UVA against UVB-induced erythemdedema and systemic suppression of contact hypersensitivity. The UVA immunoprotection was mediated by the induction of the stress enzyme heme oxygenase-1 (HO-1) in the skin, protection of the cutaneous Th1 cytokines interferon-gM (IFN-,) and IL-12 and inhibition of the UVB-induced expression of the Th2 cytokine IL-10. In this study, we seek evidence for an immunological waveband interaction when UVA and UVB are administered concurrently to hairless mice as occurs during sunlight exposure in humans. A series of spectra providing varying ratios of UVA/UVB were developed, with the UVA ratio increased to approximately 3.5 times the UVA component in solar simulated UV (SSUV). We report that progressively increasing the UVA component of the radiation while maintaining a constant UVB dose resulted in a reduction of both the erythemdedema reaction and the degree of systemic immunosuppression, as measured as contact hypersensitivity. The UVA-enhanced immunoprotection was abrogated in mice treated with a specific HO enzyme inhibitor. UVA-enhanced radiation also upregulated the expression of cutaneous IFN-, and IL-12 and inhibited expression of both IL-6 and IL-10, compared with the activity of SSUV. The results were consistent with the previously characterized mechanisms of photoprotection by the UVA waveband alone and suggest that the UVA component of solar UV may have beneficial properties for humans. [source]

Molecular Responses to Stress Induced in Normal Human Caucasian Melanocytes in Culture by Exposure to Simulated Solar UV,

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005
Laurent Marrot
ABSTRACT Melanocytes play a central role in the response of skin to sunlight exposure. They are directly involved in UV-induced pigmentation as a defense mechanism. However, their alteration can lead to melanoma, a process where the role of sun overexposure is highly probable. The transformation process whereby UV damage may result in melanoma initiation is poorly understood, especially in terms of UV-induced genotoxicity in pigmented cells, where melanin can act either as a sunscreen or as a photosensitizer. The aim of this study was to analyze the behavior of melanocytes from fair skin under irradiation mimicking environmental sunlight in terms of spectral power distribution. To do this, normal human Caucasian melanocytes in culture were exposed to simulated solar UV (SSUV, 300,400 nm). Even at relatively high doses (until 20 min exposure, corresponding to 12 kJ/m2 UV-B and 110 kJ/m2 UV-A), cell death was limited, as shown by cell viability and low occurrence of apoptosis (caspase-3 activation). Moreover, p53 accumulation was three times lower in melanocytes than in unpigmented cells such as fibroblasts after SSUV exposure. However, an important fraction of melanocyte population was arrested in G2-M phase, and this correlated well with a high induction level of the gene GADD45, 4 h after exposure. Among the genes involved in DNA repair, gene XPC was the most inducible because its expression increased more than two-fold 15 h after a 20 min exposure, whereas expression of P48 was only slightly increased. In addition, an early induction of Heme Oxygenase 1 (HO1) gene, a typical response to oxidative stress, was also observed for the first time in melanocytes. Interestingly, this induction remained significant when melanocytes were exposed to UV-A radiation only (320,400 nm), and stimulation of melanogenesis before irradiation further increased HO1 induction. These results were obtained with normal human cells after exposure to SSUV radiation, which mimicked natural sunlight. They provide new data related to gene expression and suggest that melanin in light skin could contribute to sunlight-induced genotoxicity and maybe to melanocyte transformation. [source]

Leukocytoclastic vasculitis in urticaria induced by sun exposure

PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 1 2007
Giuseppe Stinco
Background: Solar urticaria manifests itself immediately after solar or artificial light exposure and disappears a little later. Histopathologic findings of solar urticaria are essentially identical to those of classic urticaria. Case report: We report a 41-year-old man who developed urticarial lesions some hours after sunlight exposure, which resolved after approximately 1 week. Histologic examination of the lesions evidenced a leukocytoclastic vasculitis. Conclusion: In a literature review we found one case of solar urticaria with histologic aspects of leukocytoclastic vasculitis. [source]

Serum levels of vitamin D, sunlight exposure, and knee cartilage loss in older adults: The Tasmanian older adult cohort study

Doxycycline-induced staining of permanent adult dentition

AUSTRALIAN DENTAL JOURNAL, Issue 4 2005
E. Ayaslioglu
Abstract Background: Doxycycline is the most effective antibiotic for managing brucellosis. Although it is relatively free from side effects, complications involving the skin, nails and teeth may rarely be encountered. Methods: Four patients with brucellosis developed yellow-brown discolouration of teeth following a 30,45 day course of doxycycline therapy during summer at a dose of 200mg/day. Results: All four patients were diagnosed as having doxycycline-induced staining of the permanent dentition. In all cases, the staining completely resolved and the teeth recovered their original colour following abrasive dental cleaning. Conclusions: These observations indicate that the incidence of staining of the permanent dentition, as a complication of doxycycline, may be much higher than the literature indicates, especially if treatment is administered during summer months. Fortunately, this complication is reversible and does not require termination of doxycycline therapy. Complete resolution following abrasive cleaning may suggest that an extrinsic mechanism within the dental milieu may be involved in its pathogenesis. Strict avoidance of sunlight exposure during high-dose, long-term doxycycline therapy might prevent the development of this complication. [source]

Occupational sunlight exposure and risk of renal cell carcinoma,,

CANCER, Issue 8 2010
Sara Karami PhD
Abstract BACKGROUND: Recent findings indicate that vitamin D obtained from ultraviolet (UV) exposure may reduce the risk of several different cancers. Vitamin D is metabolized to its active form within the kidney, which is the major organ for vitamin D metabolism and activity. Because both the incidence of renal cell carcinoma (RCC) and the prevalence of vitamin D deficiency have increased over the past few decades, in the current study, the authors explored whether occupational UV exposure was associated with RCC risk. METHODS: A hospital-based, case-control study of 1097 patients with RCC (cases) and 1476 controls was conducted in 4 Central and Eastern European countries. Demographic and occupational information was collected to examine the association between occupational UV exposure and RCC risk. RESULTS: A significant reduction (24%-38%) in the risk of RCC was observed with increasing occupational UV exposure among men who participated in the study. No association between UV exposure and RCC risk was observed among women who participated. When the analyses were stratified by latitude as another estimate of sunlight intensity, a stronger reduction (71%-73%) in the risk of RCC was observed between UV exposure and cancer risk among men who resided at the highest latitudes. CONCLUSIONS: The current results suggested that, among men, there is an inverse association between occupational UV exposure and the risk of RCC. Replication studies are warranted to confirm these results. Cancer 2010. Published 2010 by the American Cancer Society. [source]

Keratosis lichenoides chronica in childhood

CLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 4 2002
P. Redondo
Summary Keratosis lichenoides chronica (KLC) is a rare chronic disorder of keratinization characterized by lichenoid hyperkeratotic papules arranged in a linear pattern, erythematosquamous plaques and seborrhea-like dermatitis on the face. We report a 2-year-old girl diagnosed with KLC whose lesions, arranged in symmetrical linear fashion, improved after sunlight exposure during the summer. [source]