Induction Of Erythema Research Articles

Thermal measurement of erythema across skin tones: Implications for clinical identification of early pressure injury

AimTo assess the effectiveness of thermography, colorimetry, and oximetry at detecting temperature changes after erythema induction across diverse skin tones in healthy adults. Materials and methodsErythema was induced at the forearm and ulnar head (UH) using a cupping device. Temperature via thermal image, erythema value via colorimeter, and oxygen saturation via oximeter were collected immediately and 5–10 min (delayed) after cupping at both sites. ResultsAt the forearm, the delayed timepoint was significantly warmer than baseline. At the UH, the immediate timepoint was significantly colder than baseline. Erythema increased at both timepoints and both locations. The correlation between temperature change and erythema change was weak. Change in temperature did not differ between skin tone groups. The Intermediate Low Eumelanin skin tone group had more change in erythema compared to the Intermediate Mid (i.e., darkest) skin tone group immediately after cupping at the UH and at the delayed timepoint at the forearm. ConclusionsThis study observed differences in the change of erythema across skin tones but did not observe differences in temperature across skin tones. Given high variability in results, it is premature to conclude thermal imaging works equally well across all skin tones. Further research is necessary to validate the effectiveness of thermal imaging in diverse populations. Results suggest visual erythema may be a problematic indicator as less erythema was consistently noted in participants with dark skin tones. The potential of technology to increase our ability to detect erythema warrants further investigation.

Projected changes in ultraviolet index and UV doses over the twenty-first century: impacts of ozone and aerosols from CMIP6.

This study evaluated the health-related weighted ultraviolet radiation (UVR) due to the total ozone content (TOC) and the aerosol optical depth (AOD) changes. Clear-sky Ultraviolet Index (UVI), daily doses, and exposure times for erythema induction (Dery and Tery) and vitamin D synthesis (DvitD and TvitD) were computed by a radiative transfer estimator. TOC and AOD data were provided by six Earth System Models (ESMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6). For projections, we consider four Shared Socioeconomic Pathways scenarios-SSPs (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5)-and two time-slices (near: 2041-2060 and far future: 2081-2100). UVR projections showed pronounced changes for the summer hemispheres in the far future. TOC increases in mid- and high latitudes of the Southern Hemisphere caused decreases in UVR at the summer solstice. However, projections did not indicate sun-safe exposure conditions in South America, Australia, and Southern Africa. On the contrary, exposure around solar noon from 10 to 20min will still be sufficient to induce erythema in skin type III individuals throughout this century. In southern Argentina and Chile, the UVR insufficiency for vitamin D synthesis at solar noon in skin type III remains the same during this century at the winter solstice. In the Northern Hemisphere, UVI and Dery at the summer solstice should remain high (UVI ≥ 8; Dery ~ 7.0kJm-2) in highly populated locations. Above 45 °N, UVR levels cannot be enough to synthesize vitamin D in skin type III during the boreal winter. Our results show that climate change will affect human health through excess or lack of solar UVR availability.

Using Technology to Detect Erythema Across Skin Tones.

To examine the effectiveness of the ColorMeter DSM III (ColorMeter; Cortex Technology) at grouping individuals by skin tone and measuring erythema/skin discoloration after erythema induction across skin tones. This pre/post experimental study induced erythema on a convenience sample of 61 healthy adults. Skin tone at baseline was measured using the ColorMeter, Munsell Soil Color Chart 5YR (Munsell), and Pantone SkinTone Guide (Pantone) and compared with the Eumelanin Human Skin Colour Scale (Eumelanin Scale) groupings. Erythema and melanin values on the arm immediately and after recovery time were compared with baseline values. Melanin was measured at five body regions on the face and arm. Participants were predominantly women (64% [n = 39] women, 36% [n = 22] men) and young (mean, 28.8 ± 14.3 years); 5% (n = 3) were Hispanic, 26% (n = 16) Asian, 29% (n = 18) Black, 38% (n = 23) White, and 7% (n = 4) identified with more than one race. ColorMeter lightness (L*) and melanin measures were strongly correlated with both Munsell and Pantone values. Munsell skin tone groups were not aligned with Eumelanin Scale groupings. Most participants were in the Eumelanin intermediate-low group, and this changed depending on which body location melanin value was used. The change in erythema from baseline did not differ significantly across skin tone groups at the ulnar head, but on the forearm at the delayed time point, significant differences existed between light and both medium and dark skin tone groups (P = .001; 95% CI, 0.04-0.37). The ColorMeter provides an effective objective measure of skin tone and erythema/discoloration across various skin tones and may improve on current standards for detection. The proposed Eumelanin Scale-Modified provides additional sensitivity for persons with medium skin tones.

The role and safety of UVA and UVB in UV-induced skin erythema.

Different wavelengths of ultraviolet (UV) light cause skin damage through different mechanisms. Minimal erythema dose (MED) is usually used to clinically evaluate skin sensitivity to ultraviolet radiation by inducing skin erythema using ultraviolet B (UVB) or ultraviolet A (UVA) + UVB. In this study, we detected changes in the blood flow at the MED erythema caused by UVB and UVA + UVB radiation through optical coherence tomography (OCT) to explain the role of different bands of ultraviolet rays in erythema induction. Two MED irradiation areas on the subjects' back were irradiated with UVB alone or UVA + UVB (UVA: UVB = 8:1). The absolute energy of UVB remained the same in UVB and UVA+UVB. At 24 h after the irradiation, the changes in the blood flow in the MED area were detected using OCT. Compared with the blank control, the maximum blood flow depth, blood flow peak, and total blood flow of UVB-MED and UVA+UVB-MED were significantly increased. Notably, the maximum blood flow depth and blood flow peak of UVB-MED were higher than UVA+UVB-MED. There was no significant difference in total blood perfusion between UVA+UVB-MED and UVB-MED. Under the same UVB energy, the skin erythema caused by UVA + UVB was weaker than UVB alone. The analysis of local blood flow by OCT showed that the peak and maximum depth of local blood flow caused by UVB alone were significantly higher than UVA + UVB.

Hybrid Nanogels‐Based Printable Tattoos Inspired by Lady Costume from Tang Dynasty for Monitoring Solar UV Radiation

AbstractInspired by the lady costume from Tang Dynasty, printable tattoos are prepared from hybrid nanogels to monitor ultraviolet (UV) radiation from sunshine. The hybrid poly(di(ethyleneglycol) methylether methacrylate‐co‐poly(ethylene glycol) methylethermethacrylate) nanogels containing graphitic carbon nitride (g‐C3N4) nanosheets, abbreviated as hybrid P(MA‐co‐MA300)/g‐C3N4 nanogels, are prepared by precipitation polymerization. Due to the excellent photocatalysis of the g‐C3N4 nanosheets, the dyed hybrid nanogels can be rapidly photodegraded under sunshine. Based on the linear correlation between the discoloration of dyed hybrid nanogels and the dose of solar radiation, the UV radiation from sunshine can be simply monitored by checking the color in real‐time. By applying different types of dyes, the hybrid nanogels even can be used to trace the dose for the synthesis of vitamin D, induction of erythema and risk of skin cancer simultaneously. Favored by the stickiness of acrylate‐based polymers, the hybrid nanogels can be printed to the body as tattoos to realize decoration and UV detection. By simply switching the template for printing, the tattoo patterns can be easily changed according to personal interests and applied position on the human body. Therefore, the present hybrid nanogels can be a promising candidate to monitor the solar radiation dose and decorate the human body.

Erythemal and vitamin D weighted solar UV dose-rates and doses estimated from measurements in mainland France and on Réunion Island.

Solar UV radiation causes beneficial and detrimental changes in human health. International and national Health agencies recommend avoiding sun exposure when the solar rays are strongest (typically 2h before and after solar noon). In this study we detail and refine such recommendations. We estimated biologically-effective radiation (inductive of erythema and pre-vitamin D) using spectral solar UV radiation measurements on a horizontal plane at three French sites equipped with spectroradiometers: Villeneuve d'Ascq (VDA) (North of France); Observatoire de Haute-Provence (OHP) (French Southern Alps); and Saint-Denis de La Réunion (SDR) on Réunion Island, in the Indian Ocean. These sites are very different: VDA is a semi-urban site in a flat region, OHP a rural mountainous site and SDR a coastal urban site on a small mountainous island. Biologically active radiation was analyzed by studying erythema induction and measuring pre-vitamin D synthesis. Dose-rates, doses and times for sunburn induction and vitamin D production were derived. Regarding the level of vitamin D dose considered here (1000IU), we found that at mainland sites time required for vitamin D synthesis was relatively long, even around solar noon, in winter months this could be 2-3h for phototype II individuals exposing their face and hands. In the tropics vitamin D could always be synthesized in a reasonable time (e.g. 20min in winter). By contrast, in summer, the required duration times (exposing face, hands, arms and legs) are very short, approximately 2-4min on the mainland and 1min in the tropics for phototype II individuals. In all skin phototypes the duration of sun exposure required to induce erythema was generally longer than that to produce vitamin D. These quantitative results, obtained using an instrument measuring on a horizontal plane and with an unobstructed view, do not represent realistic values for human exposure. To account for realistic human body exposure, received doses and times of exposure were adjusted. Our study shows that, mostly in summer, the time periods where limited solar exposure is recommended should be extended, especially at low latitude locations.

Solar ultraviolet doses and vitamin D in a northern mid-latitude

Solar ultraviolet (UV) radiation is one of the most important factors in the development of skin cancer in human, solar erythema and skin aging. Nevertheless, numerous studies have shown the benefits of UV solar radiation in moderate doses, such as the reduction of blood pressure and mental health, treatment of various diseases, and the synthesis of vitamin D in the skin.This paper analyses data from solar ultraviolet erythemal (UVER) irradiance in W/m2 measured in a northern mid-latitude as Valencia (Spain) for the period 2003–2010. To estimate effective solar UV radiation in the production of vitamin D (UVD) we used the relationship proposed by McKenzie et al. (2009). It was obtained for one month for each season the minimum exposure time needed around solar noon and at 9 UTC and 15 UTC (Coordinated Universal Time) to obtain the recommended daily dose of 1000IU. Also, it has been calculated time for erythema induction around solar noon for the same months.The median UVER daily dose during the summer months was 4000J/m2day, and 700J/m2day in winter. With regard to UVD, the median UVD daily dose in summer season was 7700J/m2day, and in winter it was 1000J/m2day.Around noon in January it takes more than two hours of solar exposure to obtain the recommended daily dose of vitamin D, whereas the rest of the year range between 7min on July and 31min on October. For the same months around noon, exposure times to produce erythema were obtained, these being of higher value to the previous.The results show that it is difficult to obtain the recommended vitamin D doses in winter in a northern mid-latitude, as the human body is almost entirely covered in this season.

A new hair follicle-derived human epidermal model for the evaluation of sunscreen genoprotection

Induction of skin cancer is the most deleterious effect of excessive exposure to sunlight. Accurate evaluation of sunscreens to protect the genome is thus of major importance. In particular, the ability of suncare products to prevent the formation of DNA damage should be evaluated more directly since the Sun Protection Factor is only related to erythema induction. For this purpose, we developed an in vitro approach using a recently characterized reconstituted human epidermis (RHE) model engineered from hair follicle. The relevance of this skin substitute in terms of UV-induced genotoxicity was compared to ex vivo explants exposed to solar-simulated radiation (SSR). The yield of bipyrimidine photoproducts, their rate of repair, and the induction of apoptosis were very similar in both types of skin samples. In order to evaluate the protection afforded by sunscreen against DNA damage, bipyrimidine photoproducts were quantified in tissue models following SSR exposure in the presence or absence of a SPF50+ formula. A rather high DNA protection factor of approximately 20 was found in RHE, very similar to that determined for explants. Thus, RHE is a good surrogate to human skin, and also a convenient and useful tool for investigation of the genoprotection of sunscreens.

Inhibitory Effects of Dietary Spirulina platensis on UVB-Induced Skin Inflammatory Responses and Carcinogenesis

Reactive oxygen species produced in response to UVR are important in skin tumor development. We have previously reported that deficiency of the Ogg1 gene, encoding the repair enzyme for 8-oxo-7,8-dihydroguanine (8-oxoG), increases skin tumor incidence in mice upon repetitive UVB exposure and modulation of UVB-induced inflammatory response. Spirulina platensis is used as a human food supplement because it contains abundant nutritional and antioxidant components. Therefore, we investigated the inhibitory effects of S. platensis on UVB-induced skin tumor development in Ogg1 knockout-(KO) mice and the wild-type (WT) counterpart. Dietary S. platensis suppressed tumor induction and development in both genotypes compared with our previous data without S. platensis. Induction of erythema and ear swelling, one of the hallmarks of UVB-induced inflammatory responses, was suppressed in the skin of Ogg1-KO mice and albino hairless mice fed with dietary S. platensis. Compared with untreated mice, S. platensis-administered mice showed significantly reduced 8-oxoG formation in the skin after UVB exposure. Moreover, we found that S. platensis effectively downregulated the signal proteins p38 mitogen-activated protein kinase, stress-activated protein kinase/c-Jun N-terminal kinase, and extracellular signal-regulated kinase after UVB exposure especially in Ogg1-KO mice. Our results suggest that S. platensis exerts antitumor effects against UVB irradiation in the skin through its anti-inflammatory and antioxidant effects.

A new formula for a mild body cleanser: sodium laureth sulphate supplemented with sodium laureth carboxylate and lauryl glucoside

Sodium laureth sulphate (SLES) is an anionic detergent, which has been used globally for personal care products because of its mildness and good foaming ability. However, SLES is somewhat invasive and stimulatory to the skin, and many consumers with sensitive skin desire milder detergents for daily use skin cleansers. We enhanced the mildness of SLES by formulating it with sodium laureth carboxylate (AEC) and lauryl glucoside (LG). In skin soak tests, 5% detergent solutions were applied to the forearms of 10 Japanese healthy volunteers for 30min followed by washing with tap water once a day for 4days. Twenty-four hours after the last treatment, cutaneous capacitance measurements and visual analyses were performed. In a controlled usage study, 16 Japanese healthy volunteers used the test body cleanser for 4weeks. Assessment of efficacy and mildness was conducted prior to the start of the study and at the end of week 4 by cutaneous conductance, dermoscopic evaluation of the stratum corneum and visual assessment by a dermatologist. In soak tests, cutaneous capacitance was significantly decreased on the soap-treated region and on the SLES-treated region. No significant decrease was identified on the SLES/AEC/LG-treated region with less induction of erythema or dryness. In the controlled usage study, no significant changes in cutaneous conductance or texture or damage of corneocytes on the forearm and lower thigh were found. However, visual assessment revealed a significant decrease in scaling and erythema on the lower thigh after 4weeks of usage with an improvement of the discomfort of the consumer. The favourability rating of this formulated detergent in several questionnaire items was very good. The newly formulated skin cleanser with the combination of anionic surfactants SLES and AEC and the non-ionic surfactant LG provides a mild surfactant with a satisfactory cleansing activity for body washing.

Investigation on the capability of polysulphone for measuring biologically effective solar UV exposures

Polysulphone (PS) dosimetry is a well-known technique broadly used to assess the erythemally effective solar UV dose received by anatomical sites (personal exposure). We investigate the capability of PS dosimetry to convert doses absorbed by PS badges into biologically effective solar UV exposures taking as examples two relevant effects for human skin: erythema induction and pre-vitamin D3 production. PS calibration curves for erythemal and pre-vitamin D3 were distinctly determined by using an empirical relationship between the biologically effective UV exposures and the PS absorbance change. This relationship is parameterized by a coefficient, distinct for each of the two considered biological effects, multiplying the same cubic polynomial function. It is shown how the multiplying coefficient is related to the ratio between the biologically effective and the PS weighted irradiances which is the prevailing factor affecting the accuracy of the calibration and, consequently, the capability of PS films for measuring biologically effective solar UV exposures. The points addressed in this paper can be extended to other biological effects of interest whose action spectra have some similarity with the PS film response.

The effect of head size/shape, miscentering, and bowtie filter on peak patient tissue doses from modern brain perfusion 256‐slice CT: How can we minimize the risk for deterministic effects?

To determine patient-specific absorbed peak doses to skin, eye lens, brain parenchyma, and cranial red bone marrow (RBM) of adult individuals subjected to low-dose brain perfusion CT studies on a 256-slice CT scanner, and investigate the effect of patient head size∕shape, head position during the examination and bowtie filter used on peak tissue doses. The peak doses to eye lens, skin, brain, and RBM were measured in 106 individual-specific adult head phantoms subjected to the standard low-dose brain perfusion CT on a 256-slice CT scanner using a novel Monte Carlo simulation software dedicated for patient CT dosimetry. Peak tissue doses were compared to corresponding thresholds for induction of cataract, erythema, cerebrovascular disease, and depression of hematopoiesis, respectively. The effects of patient head size∕shape, head position during acquisition and bowtie filter used on resulting peak patient tissue doses were investigated. The effect of eye-lens position in the scanned head region was also investigated. The effect of miscentering and use of narrow bowtie filter on image quality was assessed. The mean peak doses to eye lens, skin, brain, and RBM were found to be 124, 120, 95, and 163 mGy, respectively. The effect of patient head size and shape on peak tissue doses was found to be minimal since maximum differences were less than 7%. Patient head miscentering and bowtie filter selection were found to have a considerable effect on peak tissue doses. The peak eye-lens dose saving achieved by elevating head by 4 cm with respect to isocenter and using a narrow wedge filter was found to approach 50%. When the eye lies outside of the primarily irradiated head region, the dose to eye lens was found to drop to less than 20% of the corresponding dose measured when the eye lens was located in the middle of the x-ray beam. Positioning head phantom off-isocenter by 4 cm and employing a narrow wedge filter results in a moderate reduction of signal-to-noise ratio mainly to the peripheral region of the phantom. Despite typical peak doses to skin, eye lens, brain, and RBM from the standard low-dose brain perfusion 256-slice CT protocol are well below the corresponding thresholds for the induction of erythema, cataract, cerebrovascular disease, and depression of hematopoiesis, respectively, every effort should be made toward optimization of the procedure and minimization of dose received by these tissues. The current study provides evidence that the use of the narrower bowtie filter available may considerably reduce peak absorbed dose to all above radiosensitive tissues with minimal deterioration in image quality. Considerable reduction in peak eye-lens dose may also be achieved by positioning patient head center a few centimeters above isocenter during the exposure.

Effects of p-coumaric acid on erythema and pigmentation of human skin exposed to ultraviolet radiation

It has been recently recognized that p-coumaric acid (PCA) is a strong inhibitor of cellular melanogenesis. To evaluate the erythema-suppressive and skin-lightening effects of PCA after topical application to human skin. The control and PCA cream products were applied twice daily to the skin of the forearm of 21 subjects before and after ultraviolet (UV) irradiation to determine whether they could prevent erythema formation and pigmentation. The cream products were also applied to different areas only after the induction of erythema or pigmentation to determine whether they could have a depigmenting effect. A 7-day application of control and PCA cream products before UV irradiation decreased UV-induced erythema formation by 31% and 77%, respectively, compared with untreated skin. When the PCA cream was applied after UV irradiation, its effects on skin colour or pigmentation were less remarkable. However, the melanin index was significantly decreased at the sites treated with PCA cream for 70 days compared with control sites, and the Individual Typology Angle (ITA°) value was increased significantly. Of the 21 subjects, 2 had mild adverse skin reactions to both the PCA and control creams. These results suggest that PCA cream can reduce UV-induced erythema formation and subsequent pigmentation in human skin.

Assessment of the Photoprotection Properties of Sunscreens by Chromatographic Measurement of DNA Damage in Skin Explants

Evaluation of the photoprotection provided by sunscreens is performed either through the induction of erythema and expressed as the sun protection factor (SPF), or by the UVA-mediated persistent pigment darkening (PPD). None of these two endpoints has a link with skin cancer, the most deleterious consequence of excess exposure to solar UV radiation. We thus set up a complementary approach to evaluate the protection provided by sunscreens to the genome of human skin. This is based on the quantification of the thymine cyclobutane dimer (TT-CPD), the main DNA lesion induced by both UVB and UVA radiations. Irradiations were performed ex vivo on human skin explants and the level of TT-CPD in DNA was determined by HPLC associated with tandem mass spectrometry. The technique was first optimized and validated with three standard sunscreens. The study was then extended to the evaluation of a commercial high SPF sunscreen exhibiting efficient UVA photoprotection. The DNA protecting factor was found to reflect the ratio between UVB and UVA photoprotection, although the absolute values of the genomic protection were, as a general trend, lower than either SPF or PPD. These data show the usefulness of the proposed approach for the evaluation of the genoprotection afforded by sunscreens.

132 LOW-LEVEL LASER IRRADIATION IN THE COMPLEX THERAPY OF PATIENTS WITH COMPLICATED FORMS OF CHOLELITHIASIS

1,4,8-Trimethylfuro[2,3-h]quinolin-2(1H)-one (compound 5a) is the most interesting derivative among some new furoquinolinones prepared with the aim of moderating the strong toxic effects of 1,4,6,8-tetramethyl derivative (FQ), a powerful potential drug for photomedicine. Compound 5a showed a photobiological activity lower than FQ, but considerable higher than 8-MOP, the furocoumarin used in clinical photomedicine; contrary to classic furocoumarins, 5a induced a strong inhibition of protein synthesis in mammalian cells. Genotoxicity and skin erythema induction, the main side effects of both FQ and 8-MOP photosensitization, are virtually absent with 5a. This behavior seems to be connected to its particular reaction mechanism: differently from furocoumarin derivatives, 5a induced low levels of DNA-protein and no inter-strands cross-links, but formed covalent RNA-protein linkages, lesions not observed with known furocoumarins. Moreover, compound 5a generated reactive oxygen species to a considerable extent. For these features, compound 5a appears to be a new photosensitizing agent whose special activity deserves to be deeply investigated.

Efficacy of oleuropein against UVB irradiation: preliminary evaluation

Oleuropein, a phenolic compound derived from olive leaves and oil, is known to possess several biological properties, many of which may be attributed to its antioxidant and free radical-scavenging activities. Nevertheless, up to now, the cosmetic activity of this molecule has not been extensively investigated. The aim of this work was to evaluate the cosmetic properties of oleuropein against UVB-induced erythema. To this end, an emulsion and an emulgel containing oleuropein were prepared, applied and evaluated on healthy volunteers who had undergone UVB irradiation to investigate its protective and/or lenitive activity. Protective effect was assayed by application of topical preparations before irradiation and lenitive effect was evaluated after erythema induction. Vitamin E was used as the reference compound. Our study was carried out by using noninvasive techniques to assess specific skin parameters: barrier function, skin colour and microcirculation. Results clearly showed that oleuropein formulations highlighted lenitive efficacy by reducing erythema, transepidermal water loss and blood flow of about 22%, 35% and 30% respectively. The study allowed us to point out the lenitive property of oleuropein, opening the way to further trials to deepen our specific knowledge about this natural molecule, which could be used in association with other active ingredients in cosmetics to repair UV damages.

Evaluation of the Antioxidant Capacity and Preventive Effects of a Topical Emulsion and Its Vehicle Control on the Skin Response to UV Exposure

Supplying topical exogenous antioxidants to the skin may prevent or minimize free radical-induced damaging. This study determines antioxidative capacity of a topical skin care emulsion (an oil-in-water vitamin E-containing formulation) versus its vehicle on human skin that was exposed to ultraviolet radiation (UVR) by utilizing a photochemiluminescence device and biophysical methods. Ten healthy Caucasians (3 male and 7 female; mean age 47 ± 10 years) were enrolled. In a randomized and double-blind manner, a pH-balanced vitamin E emulsion or its vehicle control was applied onto predesignated forearm prior to UVR exposure. Thirty minutes after application, these test sites were exposed to a UV light to induce the minimal erythema dose. One untreated site served as a blank control. Visual scoring and instrumental measurements were recorded at baseline and at 24 h and 48 h thereafter. At day 3, after completing instrumental measurements, each test site was stripped three times in a consecutive manner with a proprietary adhesive tape disc. These tapes were quantified for antioxidant capacity using a photochemiluminescence device.Vitamin E emulsion and vehicle control significantly (p < 0.05) suppressed visual scores when compared with blank control at day 2 and day 3 after UV exposure. However, vitamin E emulsion showed significantly (p < 0.05) lower visual scores when compared with vehicle control at day 2 and day 3 after UV exposure.Also,vitamin E emulsion and its vehicle control significantly (p < 0.05) diminished skin color measurement (a*) values when compared with blank control at day 2 and day 3 after UV exposure. At day 2 after UV exposure, only vitamin E emulsion significantly (p < 0.05) reduced skin blood flow volume when compared with blank control. Vitamin E emulsion and its vehicle control showed significant (p < 0.05) reduction of blood flow volume when compared with blank control at day 3 after UV exposure. Vitamin E emulsion and its vehicle control proved effective in preventing induction of erythema and reducing inflammatory damage caused by UV exposure. The effect of vitamin E emulsion exceeded that of an ‘active control’.

Comparisons of biologically effective doses of solar UV-radiation determined with spore dosimetry and spectral photometry in 2000–2003 at Southern Space Observatory, Brazil

In order to assess the impact of solar-UV radiation on biosphere and human health, spore dosimetry and spectral photometry have been performed in parallel at the Southern Space Observatory, São Martinho da Serra in the State of Rio Grande do Sul (southern region of Brazil, latitude 29.44°S, longitude 53.8°W). Daily and monthly cumulative doses obtained from spore dosimeters were compared with the doses derived from the integration of the daily effectiveness spectra obtained by multiplications of the spectral irradiance from Brewer spectrophotometers with the action spectra for spore inactivation and erythema induction. For daily exposures performed on 24 days in 2002–2003, the values of the observed spore inactivation doses (SID) and the calculated ones were closely correlated with a mean ratio (observed SID/calculated SID) of 0.7 ± 0.3, while the values of the observed SID were regressed to the erythemal doses (MED) by a power function with a correlation coefficient r 2 ∼ 0.9. For cumulative monthly doses, the values of calculated SID and MED were regressed to the observed values of SID by power functions for each year with r 2 = 0.5–0.9 and r 2 = 0.5–0.9, respectively. The applicability of the spore dosimetry for continuous long-term monitoring of biologically effective doses of solar-UV radiation has been verified in this work.

1,4,8‐Trimethylfuro[2,3‐H]quinolin‐2(1H)‐one, a New Furocoumarin Bioisoster.

AbstractFor Abstract see ChemInform Abstract in Full Text.

1,4,8-Trimethylfuro[2,3- H]quinolin-2(1 H)-one, a new furocoumarin bioisoster

1,4,8-Trimethylfuro[2,3-h]quinolin-2(1H)-one (compound 5a) is the most interesting derivative among some new furoquinolinones prepared with the aim of moderating the strong toxic effects of 1,4,6,8-tetramethyl derivative (FQ), a powerful potential drug for photomedicine. Compound 5a showed a photobiological activity lower than FQ, but considerable higher than 8-MOP, the furocoumarin used in clinical photomedicine; contrary to classic furocoumarins, 5a induced a strong inhibition of protein synthesis in mammalian cells. Genotoxicity and skin erythema induction, the main side effects of both FQ and 8-MOP photosensitization, are virtually absent with 5a. This behavior seems to be connected to its particular reaction mechanism: differently from furocoumarin derivatives, 5a induced low levels of DNA-protein and no inter-strands cross-links, but formed covalent RNA-protein linkages, lesions not observed with known furocoumarins. Moreover, compound 5a generated reactive oxygen species to a considerable extent. For these features, compound 5a appears to be a new photosensitizing agent whose special activity deserves to be deeply investigated.