In silico affinity between analgesic/anti-inflammatory drugs and the transient receptor potential A1 to predict potential pharmacological managing approaches for bleaching sensitivity.

Reducing in-office tooth bleaching sensitivity represents a challenge for professionals. Researchers have associated the block of the pain receptor TRPA1 with reducing bleaching sensitivity. However, the chemical affinity of analgesic/anti-inflammatory drugs to the TRPA1 needs to be verified. To perform a virtual screening of multiple drugs (analgesic and anti-inflammatory drugs) to verify chemical affinity for the TRPA1 receptor. The crystal structure of the TRPA1 receptor proteins was retrieved from the Protein Data Bank. The SMILES codes of the ligands were extracted from PubChem. The binding energy of the complex was obtained in ∆G - kcal/mol by AutoDock Vina© and replicated in the webservers SwissDock©, Dockthor©, and CbDock©. LigPlus© confirmed the binding sites. Codeine and dexamethasone showed regularity among all servers, even showing binding energy values of -7.9 kcal/mol for codeine and -8.1 kcal/mol for dexamethasone. Codeine and dexamethasone may be potential drugs to manage tooth bleaching sensitivity if they reach the dental pulp TRPA1 receptor.

Two phytocompounds from Schinopsis brasiliensis show promising antiviral activity with multiples targets in Influenza A virus.

Influenza A virus, the main flu agent, affects billions of people worldwide. Conventional treatments still present limitations related to drug-resistance and severe side effects. As a result, natural product-derived molecules have been increasingly investigated as prospect drug candidates. Therefore, the aim of this study was to investigate the possible anti-flu activity and to evaluate the toxicity and pharmacokinetic parameters, by in silico approaches, of the Schinopsis brasiliensis Engl. phytochemical compounds. Nine phytocompounds and six antiviral drugs (Amantadine, Umifenovir, Favipiravir, Nitazoxanide, Oseltamivir, Zanamivir) were selected for the analyses against four Influenza A proteins: neuraminidase, polymerase basic protein 2, hemagglutinin and M2 ion channel protein. The molecular docking, the predicted antiviral activity, the predicted toxicity and the pharmacokinetics investigations were conducted. The obtained results demonstrated that Syringaresinol and Cycloartenone display promising in silico antiviral activity (binding energy < 5.0 and ≥ 9.0 kcal/mol) and safety (low toxicity than commercial anti-flu drugs). Overall, this study corroborated the hypothesis that S. brasiliensis barks extract has a biological activity against Influenza A virus. Additionally, Syringaresinol and Cycloartenone have multiple targets in Influenza A virus and showed themselves as the most promising phytocompounds to be isolated and considered for the therapeutic arsenal against the flu.

Effect of vitamin D supplementation and ultraviolet B exposure on serum 25-hydroxyvitamin D concentrations in healthy volunteers: a randomized, crossover clinical trial.

BACKGROUND: Solar ultraviolet (UV) radiation during the summer and vitamin D supplementation are two major sources of vitamin D for humans at northern latitudes. However, little is known about the relative efficiency of these two vitamin D sources. OBJECTIVES: The main goal was to compare the efficiency of high-dose oral vitamin D3 supplementation (2000 IU per day for 30 days) with a simulated summer UV exposure [10 sunbed sessions to a total dose of 23·8 standard erythema doses (SED)] to improve vitamin D status. METHODS: Healthy volunteers were randomized into two groups: group 1 received vitamin D supplementation followed by 10 whole-body sunbed exposures; group 2 started with 10 sunbed exposures followed by vitamin D supplementation. RESULTS: The oral supplementation with vitamin D3 resulted in a mean (SEM) serum 25-hydroxyvitamin D [25(OH)D] increase of 25·3 (5·4) nmol L(-1) . A similar increase, 19·8 (5·4) nmol L(-1) , was observed after simulated summer UV exposure. At the end of the study, serum 25(OH)D concentrations were similar in both groups. CONCLUSIONS: Twice-weekly whole-body sunbed exposure to a dose of 4·8 SED is equal to 2000 IU daily of oral vitamin D supplementation for 30 days and enough to achieve and maintain serum 25(OH)D concentrations > 75 nmol L(-1) in ~55% of cases. Based on our calculations, this dose corresponds to a cumulative weekly whole-body exposure of 3·4 SED (~ 40 min around midday during the summer at the latitude of Oslo).

Malignant melanomas on head/neck and foot: differences in time and latitudinal trends in Norway.

BACKGROUND: Cutaneous malignant melanoma (CMM) incidence continues to increase in many parts of the world. Solar ultraviolet (UV) radiation is the main environmental risk factor for CMM. Different body locations are subjected to different doses and exposure patterns of solar UV. Time and latitudinal trends of CMMs on shielded and exposed skin give valuable information about the aetiology of these cancers. In this study, we have compared the time and latitudinal trends of CMM incidence on skin areas which are chronically (head and neck) and rarely (foot) exposed to UV radiation, to gain more information about the relationship between sun doses, exposure patterns and melanomagenesis. METHODS: We have analysed epidemiological data from the Cancer Registry of Norway, for foot and head and neck CMM for two time periods: 1966-1986 and 1987-2007. RESULTS: Cutaneous malignant melanoma incidence rate on head and neck has increased with time, while incidence rates of foot CMM have remained almost constant with time in Norway. There is a large north-south gradient in incidence rates of CMM on head and neck in Norway, while there is almost no north-south gradient for CMM incidence on foot. CONCLUSIONS: Comparisons of time trends and latitudinal trends of the incidence rates of CMM on head/neck and on foot indicate that solar radiation plays a role in the induction of the former CMM but probably not for the latter.

Comparison of the time and latitude trends of melanoma incidence in anorectal region and perianal skin with those of cutaneous malignant melanoma in Norway.

BACKGROUND: Melanoma incidence is increasing in many parts of the world. The main environmental risk factor is exposure to solar radiation. However, melanomas may arise also on non-sun-exposed areas (uveal and mucosal melanomas) and little is known about a possible relationship between sun exposure and melanoma on such locations. OBJECTIVES: We have compared the time and latitude trends of melanoma incidence in the anorectal region and perianal skin (non-sun-exposed sites) with those of cutaneous malignant melanoma (CMM) (sun-exposed skin) to gain more information about the relationship between sun exposure and melanoma on such sites. METHODS: We analysed epidemiological data from the Cancer Registry of Norway for melanomas of the anorectal mucosa, perianal skin and overall CMM for the time period 1966-2007. RESULTS: We found that melanoma incidence on these shielded sites tends to decrease or remain constant over a period during which the CMM rates increase. This is true both in the North and in the South regions of Norway. Comparison of latitudinal trends of the incidence rates of CMM and melanoma on these shielded sites shows that there is no latitude gradient for melanoma of the anorectal mucosa and perianal skin, whereas there is a strong one for CMM. CONCLUSIONS: The time and latitudinal trends are likely to support the assumption that melanomas on these shielded sites are not generated by ultraviolet radiation. Possible causes and significances of these trends are discussed.

Topical aminolaevulinic acid- and aminolaevulinic acid methyl ester-based photodynamic therapy with red and violet light: influence of wavelength on pain and erythema.

BACKGROUND: Photodynamic therapy (PDT) is based on the combination of an exogenously administered precursor of photosensitizer [protoporphyrin IX (PpIX)] synthesis and exposure to light. Choosing the optimal wavelength is important. Red light penetrates deeper into tissue, while violet light is more efficient in activating PpIX but does not penetrate so deeply. OBJECTIVES: We studied PpIX formation and the PDT effect after application to human skin of creams containing aminolaevulinic acid (ALA) and aminolaevulinic acid methyl ester (MAL). The aim of the study was to investigate whether the wavelength of the light used has an influence on pain sensations during topical PDT with the different prodrugs. METHODS: ALA cream (10%) and MAL cream (10%) were topically applied on the skin of 10 healthy volunteers. After 24 h the application site was exposed to 8 mW cm(-2) violet laser or to 100 mW cm(-2) red laser light. The erythema index was monitored up to 24 h after light exposure. For the first time the pain during topical ALA- and MAL-PDT was assessed by measuring the time taken for pain to occur. Also, for the first time, the intensities of the light sources were calibrated so as to have the same relative quantum efficiency. Results The pain sensation during ALA-PDT with red light came 22 s sooner than during ALA-PDT with violet light, which is statistically significant (P < 0.05). Moreover, ALA-PDT with red light gave stronger and more persistent erythema than ALA-PDT with violet light. ALA induced about three times more PpIX than MAL. No statistically significant differences were found for erythema, or for the time for pain to occur, in the case of MAL-PDT with red vs. violet light. CONCLUSIONS: Topical ALA-PDT with violet light allows longer exposure times before pain is induced and gives less erythema as compared with topical ALA-PDT with red light.

Calcitriol treatment improves methyl aminolaevulinate-based photodynamic therapy in human squamous cell carcinoma A431 cells.

BACKGROUND: Photodynamic therapy (PDT) using methyl aminolaevulinate (MAL) provides a new, approved method for treatment of skin cancer and its precursors. However, MAL-based PDT is not very efficient for poorly differentiated skin carcinoma. Thus, novel strategies to enhance the PDT effect are needed. OBJECTIVES: In order to improve the efficacy of MAL-based PDT, we investigated the effect of adding calcitriol, a prodifferentiation hormone, to human squamous cell carcinoma A431 cells in vitro. METHODS: A short course (24 h) of calcitriol pretreatment was applied in A431 cells, and, subsequently, MAL-induced protoporphyrin IX (PpIX) was measured. RESULTS: Calcitriol pretreatment of the cells elevated their PpIX levels. Furthermore, the cell damage after exposure to blue light was significantly higher in calcitriol-treated cells. Increased photoinactivation correlated with higher levels of PpIX in the calcitriol-pretreated cells. CONCLUSIONS: Calcitriol enhances MAL-based PDT in A431 cells.

Retrieval of the physiological state of human skin from UV-Vis reflectance spectra - a feasibility study.

We test the feasibility of using an accurate radiative transfer model for the coupled air-tissue system in conjunction with a classic inversion scheme based on Bayesian optimal estimation theory for retrieval of parameters describing the physiological state of human skin. To that end, we analyse ultraviolet and visible reflectance spectra from human skin measured before, immediately after, and on each day for two weeks after photodynamic treatment with the hexyl ester of ALA and exposure to red light (632 nm). For the first time, we show that it is possible to perform a simultaneous retrieval of the melanosome concentration in both the basal and the upper layers of the epidermis.

Active photosensitizers in butter detected by fluorescence spectroscopy and multivariate curve resolution.

In this study, fluorescence excitation and emission matrices and multivariate curve resolution (PARAFAC) were used to detect and characterize active photosensitizers spectrally in butter. Butter samples were packed under high (air) and low oxygen (<0.05%) atmospheres and exposed to violet, green, or red light. Six photosensitizers were found: riboflavin, protoporphyrin, hematoporphyrin, a chlorophyll a-like molecule, and two unidentified tetrapyrrols. By estimation of relative concentrations, we could follow how each sensitizer was photodegraded as function of wavelength, oxygen level, and time. The degradation rate of protoporphyrin, hematoporphyrin, chlorophyll a, and one of the tetrapyrrols correlated well (0.83-0.91) with the formation of sensory measured oxidation. The results suggest that mainly type I photoreactions were responsible for the degradation of photosensitizers in both high and low oxygen atmosphere. Type II photoreactions (generation of singlet oxygen) were involved in the oxidation of butter stored in air. The study shows that PARAFAC modeling of fluorescence landscapes is an excellent tool for studying photooxidation in complex systems.

Photodynamic therapy.

Photodynamic therapy involves administration of a tumor-localizing photosensitizing agent, which may require metabolic synthesis (i.e., a prodrug), followed by activation of the agent by light of a specific wavelength. This therapy results in a sequence of photochemical and photobiologic processes that cause irreversible photodamage to tumor tissues. Results from preclinical and clinical studies conducted worldwide over a 25-year period have established photodynamic therapy as a useful treatment approach for some cancers. Since 1993, regulatory approval for photodynamic therapy involving use of a partially purified, commercially available hematoporphyrin derivative compound (Photofrin) in patients with early and advanced stage cancer of the lung, digestive tract, and genitourinary tract has been obtained in Canada, The Netherlands, France, Germany, Japan, and the United States. We have attempted to conduct and present a comprehensive review of this rapidly expanding field. Mechanisms of subcellular and tumor localization of photosensitizing agents, as well as of molecular, cellular, and tumor responses associated with photodynamic therapy, are discussed. Technical issues regarding light dosimetry are also considered.

Measurement of lipid oxidation and porphyrins in high oxygen modified atmosphere and vacuum-packed minced turkey and pork meat by fluorescence spectra and images.

This paper illustrates that fluorescence spectroscopy and imaging can be used to measure the extent and distribution of lipid oxidation in meat. Minced turkey thighs and pork semimembranosus muscles were stored for 7 and 12 days at 4°C in high oxygen (O(2)) modified atmosphere packages and vacuum. Turkey meat packed in high O(2) atmosphere was oxidised already after 7 days of storage. The sensory rancid odour score was 4.7 (on a scale from 1 to 9) and the TBARS value was 1.86mg MDA/kg. There was also an increase in fluorescence emission intensity in the 410-550nm region, which arises from lipid oxidation products. The combination of unsaturated fatty acids and access to O(2) resulted in lipid oxidation gradients in the turkey meat samples, and these gradients were clearly visualised by fluorescence images. In comparison, pork meat was more stable against lipid oxidation, with TBARS values <0.2mg MDA/kg and no development of fluorescent lipid oxidation products was detected. The fluorescence spectra measured in the present experiment suggest that turkey thighs and pork semimembranosus muscle in addition to protoporphyrin also have a natural content of Zn protoporphyrin. The porphyrin content was higher in pork meat than in turkey meat. It increased during storage time when the meat was packed in vacuum, and it decreased with O(2) availability. The distribution of porphyrins in the meat was visualised by fluorescence imaging.

Photodynamic inactivation of synchronized human cells in vitro in the presence of hematoporphyrin.

Dose-response curves for inactivation of synchronized cells from the human cell line NHK 3025 in the presence of hematoporphyrin and light are shown. Sensitivity toward photodynamic inactivation is increasing as the cells move in the cell cycle from G1 to mid-S. The increase is mostly due to a change in the extent of the shoulder of the dose-response curve at low doses. The quasithreshold dose (Dq) is high in early G1 and much lower in mid-S. No great variations were found in the slope (1/Do) of the dose-response curves at high doses. The shape of the dose-response curves indicates a higher capacity for repair of sublethal damage in the early part of the cell cycle than in the later stages.

Oxygen dependence of the photosensitizing effect of hematoporphyrin derivative in NHIK 3025 cells.

Cells of the established line NHIK 3025 were incubated with hematoporphyrin derivative and exposed to light at different concentrations of oxygen. The efficiency of photoinactivation of the sensitized cells decreased with decreasing oxygen concentration. No photoinactivation was observed when the atmosphere above the medium overlying the cells was pure N2 gas. With 1% O2 in the atmosphere, the quantum yield of photoinactivation was reduced by 50% compared to the yield in air-saturated medium. It is hardly possible to inactivate cells in anoxic regions of a tumor by means of porphyrin sensitized photochemotherapy. In spite of this, the therapy seems to be efficient in several cases. Thus, it seems that anoxic tumor cells are inactivated in secondary reactions, probably due to breakdown of the circulatory system in the tumor.

DNA single-strand breaks and sister chromatid exchanges induced by treatment with hematoporphyrin and light or by x-rays in human NHIK 3025 cells.

Alkali-labile sites resulting in single-stranded breaks in DNA and sister chromatid exchanges are produced when human cells (NHIK 3025) in vitro are exposed to sublethal doses of light in the presence of hematoporphyrin. The irradiation doses required to reduce the survival from 1 to 0.1 for 220-kV X-rays and treatment with 10(-4) M hematoporphyrin in phosphate-buffered saline and 380 nm light were 6.2 grays and 230 J/sqm, respectively. X-rays induce about 5 times more sister chromatid exchanges and about 80% more DNA single-strand breaks than exposure to hematoporphyrin plus light when the two modalities of treatment are compared on the same level of survival. In both cases, the single-strand breaks are practically completely repaired within 15 min.

Changes in antigen expression on human FME melanoma cells after exposure to photoactivated hematoporphyrin derivative.

Exponentially growing melanoma cells of the line FME were incubated with hematoporphyrin derivative (HpD) for 1 and 18 h and subsequently exposed to light in the presence of HpD. Quantitative changes in the expression of the melanoma-associated surface antigen p250 recognized by the monoclonal antibody 9.2.27 were studied by flow cytometry. Treatment with HpD and light resulted in no immediate changes in the antigen expression. However, a few hours after light exposure a significant reduction in antigen expression was observed. For cells incubated with HpD for 1 h, the minimum expression of the antigen was observed 6 h after the irradiation, and the duration of the reduced expression was almost dose independent. On the other hand, the duration of the reduced antigen expression increased strongly with light dose for cells incubated with HpD for 18 h. In both cases antigen expression decreased exponentially with the product of drug concentration and light dose, indicating that there is no rapid mechanism by which the cells can repair the damage which leads to reduced antigen expression. Days were needed before the cells expressed a normal level of the antigen. A slight overshoot of the level of antigen expression above that for untreated cells was observed 2-5 days after light exposure depending on the incubation conditions with HpD and the light dose. At a given cell survival level (greater than 0.1), the decrease in antigen expression was more pronounced on cells incubated with HpD for 1 h than on cells incubated with the drug for 18 h.

Tumor-localizing and photosensitizing properties of the main components of hematoporphyrin derivative.

Both 3H-labeled and unlabeled hematoporphyrin derivative (HPD) were analyzed by high-pressure liquid chromatography (HPLC) and gel permeation chromatography. Four main components were isolated by HPLC, and two were isolated by gel permeation chromatography. The tumor-localizing ability of each component was tested and compared to that of 67Ga and 3H2O by injection in mice bearing Lewis lung carcinoma. The photosensitizing abilities of the HPLC-separated components in vitro were also tested. Finally, porphyrin extracts of tumors from mice given HPD were analyzed by HPLC. The tumor-localizing ability of the components increased with decreasing polarity. While crude HPD localized in tumor tissue only to the same extent as did 3H2O, Component 7 was almost as effective as was 67Ga in localizing in the tumor. The cellular uptake of HPD components increased with decreasing polarity. In accordance with this, the low-polarity components were the most effective photosensitizers.

Biological amplification factor for sunlight-induced nonmelanoma skin cancer at high latitudes.

Data for the incidence of basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) of the skin, registered for six regions of Norway during 10 years (1976-1985), were used to evaluate the biological amplification factor Ab for induction of these cancers by sunlight. Ab is the ratio of the increment in skin cancer production to the increment in causative sunlight exposure. Two different approximations were used for the action spectrum for carcinogenesis: an erythema action spectrum; and an action spectrum for mutagenesis of cells in the basal layer of the skin. These two fundamentally different approaches yielded Ab values that were similar to within about 10%: 2.1-2.3 for BCCs; and 1.6-1.8 for SCCs. Using a radiation amplification factor for ozone depletion of 0.8-1.1, we find that the total amplification factor for BCCs is within the range 1.6-2.1 and that that for SCCs is within the range 1.3-1.7 at northern latitudes of 60-70 degrees. Thus, an ozone depletion of 1% will result in an increase in the incidence of BCCs by 1.6-2.1% and of SCCs by 1.3-1.7%. There were no significant differences between the values for men and women. Neither was there any significant difference between Ab values found for skin commonly exposed to sunlight (face) and for skin sites normally covered by clothes and therefore receiving much lower exposures, in spite of the fact that the tumor density per unit skin area was a factor of 20 or more larger at the former sites. This observation, as well as the curves relating cancer incidence with annual exposure to carcinogenic sunlight, supports a power law relationship between cancer incidence and annual sun exposure. Sunlight appears to be the main cause of BCCs and SCCs even at the high latitudes of Northern Norway. All over, BCCs were found to be about 6 times more frequent than SCCs. The ratio of the incidence of BCCs to that of SCCs seemed to be independent of the latitude. Finally, BCCs were found to be equally frequent among men and women, while SCCs were found to be about twice as frequent among men as among women.

Uptake, localization, and photodynamic effect of meso-tetra(hydroxyphenyl)porphine and its corresponding chlorin in normal and tumor tissues of mice bearing mammary carcinoma.

By using a chemical extraction assay and confocal laser scanning fluorescence microscopy, the kinetic patterns of uptake, elimination, and localization of meso-tetra(hydroxyphenyl)porphine (m-THPP) and its corresponding chlorin (m-THPC) in tumors and various normal tissues of female C3D2/F1 mice bearing CaD2 mammary carcinoma were studied after an i.p. injection of either 5 mg/kg body weight of m-THPP or 1 mg/kg body weight of m-THPC. Moreover, the histological and ultrastructural alterations of the tumors were evaluated after photodynamic therapy (PDT) with m-THPP or m-THPC. The PDT efficacy with m-THPP and m-THPC was also compared. Both m-THPP and m-THPC had a similar kinetic pattern of distribution in the tumors and most normal tissues examined. The concentrations of the dyes in the tissues peaked at 24-48 h after injection. The peak values of the uptake of m-THPP by the tissues were found to decrease in the following order: spleen > urinary tract > kidney > liver > lung > tumor > heart > skin > muscle > brain. However, higher concentrations of m-THPC were taken up by the tumors than by most of the normal tissues studied except for the liver, urinary tract, and skin. m-THPP was mainly localized in the stroma of the tumors, whereas m-THPC was distributed in both vascular interstitium and neoplastic cells of the tumors. Morphological studies showed that PDT with m-THPP resulted in destructive changes in the microvasculature of the tumors, whereas m-THPC-based PDT destroyed both vascular walls and tumor cells of the tumors. The m-THPP-PDT of the tumors was much less efficient than m-THPC-PDT of the tumors, although the dose of m-THPP used was five times higher than that of m-THPC. m-THPP and m-THPC have different efficiency of sensitizing tumors to photodestruction, although they are similar with respect to hydrophobicity. This is likely due to the differences in their intratumoral localization patterns and in their absorption spectra.

Ozone depletion and its consequences for the fluence of carcinogenic sunlight.

A slight reduction of the ozone level over the northern hemisphere in the period 1969-1986 has been reported [D. Lindley, Nature (Lond.), 323: 293, 1988]. Ozone measurements performed in Oslo are in agreement with this. However, the ozone level for 1987 and 1988 was above normal, and no negative or positive trend is apparent for the last 10 years. The consequences of an ozone reduction for the fluence rate of carcinogenically effective sunlight was evaluated on the basis of recent action spectra for mutagenesis in cells, carcinogenesis in mice, and erythema induction in humans. Depending on the choice of action spectrum we find amplification factors (defined as percentage increase in yearly fluence of carcinogenically efficient sunlight per percentage reduction of the ozone level) between 1.1 and 1.3 at latitudes between 0 and 20 degrees and between 0.9 and 1.1 for Northern Europe. These estimates are significantly lower than 2.0, which is the value found when the calculations are based on the DNA absorption spectrum (R. B. Setlow, Proc. Natl. Acad. Sci. USA, 71:3363-3366, 1974).

Use of 5-aminolevulinic acid esters to improve photodynamic therapy on cells in culture.

Human tumor cells of the lines WiDr (adenocarcinoma of the rectosigmoid colon), NHIK 3025 (carcinoma of the cervix), and V79 Chinese hamster fibroblasts were treated with 5-aminolevulinic acid (ALA) and ALA esterified to C1-C3 and C6-C8 chained aliphatic alcohols (ALA-esters). In the human cell lines, esterification of ALA with the long-chain (C6-C8) alcohols was found to reduce 30-150-fold the amount of ALA needed to reach the same level of protoporphyrin IX (PpIX) accumulation as with non-esterified ALA. The long-chained ALA-esters were less efficient in stimulating PpIX formation in V79 cells, i.e., the same amount of PpIX was formed by a 1-2.6-fold lower concentration of long-chained ALA-esters than with ALA. Short-chained ALA-esters (C1-C3) induced 5 to 10 times lower PpIX accumulation than ALA in all of the cell lines. High-performance liquid chromatography and fluorescence microscopic studies indicated that esterification of ALA has neither impact on the fluorescing porphyrin species formed nor impact on their intracellular localization. The PpIX formed from ALA-esters and ALA was found to be equally efficient in sensitizing cells to photoinactivation. The present results indicate that esterified ALAs are new and promising drugs for use in photochemotherapy of cancer.