Photosensitivity

Abstract— The radical copolymerization of (p-2-ethoxycarbonyl)cyclopropyl styrene with glycidyl methacrylate has been investigated. The new cyclopropane- and epoxy-containing photosensitive copolymers have been prepared. The constant values of relative activity of the monomers have been determined and the parameters Q-e on Alfrey and Price have been calculated. The copolymerization constants of this compound (r1) with glycidyl methacrylate (r2) calculated on Feynman-Ross method are: r1 = 1.15, r2 = 0.42, respectively; values of parameters Q and e: Q1 = 1.85, e1 = -0.75, respectively. The composition and structure have been established and the photochemical investigations of the synthesized copolymer have been carried out. It has been established that structuring proceeds due to opening of cyclopropane ring, epoxide and carbonyl groups.

"Background: Patients with migraine are averse to certain visual stimuli, such as flicker and striped patterns that evoke paroxysmal EEG activity in patients with photosensitive epilepsy. Migraineurs demonstrate a hyper-responsiveness to such stimuli, and there is debate as to whether the aversion and hyper-responsiveness are due to a hyperexcitability of the cortex similar to that in patients with photosensitive epilepsy. In these patients grating patterns with certain spatial characteristics can be epileptogenic, depending critically on their movement. If the contours of the grating drift continually, the grating is not epileptogenic, but if the contours are static or if their direction is repeatedly and rapidly reversed so as to vibrate, the grating then becomes highly epileptogenic.
Methods: We compared aversion to vibrating, drifting and static gratings in migraineurs and controls. The contrast of each grating was gradually increased, but only until the participant felt discomfort, so as to obtain a contrast threshold for aversion with minimal exposure.
Results: Migraineurs had lower thresholds than the Control Group, indicating greater aversion. For both groups the threshold was higher (aversion was lower) for static than for both types of moving gratings. The drifting gratings were more aversive than the vibrating gratings when both groups were combined.
Conclusion: The findings suggest that the aversion shown by migraineurs is not attributable to a cortical hyperexcitability similar to that in photosensitive epilepsy."

To define the spectrum of the epileptic syndromes and epilepsies (other than the idiopathic epilepsies of childhood with occipital paroxysms) that can be associated with fixation-off sensitivity (FOS), delineate the electrographic types of FOS abnormalities and identify the patterns that can be associated with clinical seizures, and examine whether there may be a pure form of fixation-off sensitive epilepsy. We reviewed the clinical and video EEG data of all our patients with FOS over the last 12 years. Children with idiopathic focal epilepsies and occipital EEG paroxysms were excluded. From January 1995 to December 2006, 19 of about 8,500 patients had had one or more video-EEGs with FOS, yielding an approximate incidence of 0.2%. From the 14 patients with full clinical and EEG data available, 12 had various epilepsies that included IGE phenotypes (7), symptomatic or probably symptomatic focal (3), cryptogenic generalised (1), and adult onset idiopathic photosensitive occipital (1),...

In some, but not all countries, porphyria cutanea tarda (PCT) has been associated with chronic infection with the hepatitis C virus (HCV). Recently, PCT has also been associated with mutations in the HFE gene that are associated with HLA-linked hereditary hemochromatosis. Until now, few studies of these associations have been reported from North America. The aims of this study were: 1) to assess the prevalence of HCV infection and HFE mutations in North American patients with PCT; 2) to compare demographic and laboratory features between those who are HCV-positive and HCV-negative; and 3) to study urinary porphyrin excretions in American HCV-positive patients without clinically manifest PCT. Clinical and laboratory data, including tests for HCV and urinary porphyrins, were collected from 70 unselected patients with typical PCT. Urinary porphyrins were also measured in 110 non-PCT patients with chronic hepatitis C. Mutational analyses of the HFE gene were performed in 26 PCT patients. Thirty-nine of 70 (56%) of the PCT patients had evidence of HCV infection. Thirty-two of 39 PCT patients with HCV were men, all of whom used alcohol. In contrast, 22 of 31 PCT patients without HCV infection were women, 12 of whom had taken estrogens. The HCV-positive group was more likely to have used illicit intravenous drugs (45% vs. 0%; P = 0.01), to have had several (>4) sex partners (48% vs. 13%; P = 0.005), and less likely to have no known risk factors for HCV infection (33% vs. 78%; P = 0.004). Total urinary porphyrin excretion was the same in the two groups, but those with HCV infection had a significantly lower percentage of uroporphyrin and higher percentages of hepta-and hexa-carboxy porphyrins in urine. Sixteen of 110 (15%) HCV-positive subjects without PCT had increased urinary porphyrins, but, unlike PCT, these were mainly coproporphyrin. Forty-two percent of PCT patients carried the C282Y mutation of HFE (15% homozygous), and another 31% carried the H63D mutation (8% homozygous). Thus, 73% of PCT patients had one of these mutations. The prevalence of HCV infection (56%) and mutations in the HFE gene (73%) are high among North American patients with PCT. Alcohol and estrogen use are important additional risk factors. All PCT patients should be tested for HCV infection and for HFE gene mutations. Although HCV infection is a trigger for PCT, preclinical PCT is rare in chronic HCV hepatitis C in the United States.

Background: Patients with chronic actinic dermatitis (CAD) frequently have positive patch or photopatch tests. In our previous study (period 1987–1992), the most prominent contact allergen was the sesquiterpene lactone mix (36% of patients with CAD).Objective: To assess whether contact allergy profiles in CAD patients between 2000 and 2005 have changed in respect to our previous data (1987–1992).Patients and Methods: Fifty CAD patient records from 2000 to 2005 for patch and photopatch testing were retrospectively analysed and data were compared with that from 86 patients seen between 1987 and 1992.Results: Thirty-two (64%) and 64 (74%) patients had positive patch or photopatch tests in 2000–2005 and 1987–1992, respectively. The allergen profile has altered. A decline in sesquiterpene lactone mix positive reactions was noted: 29 (36%) patients were positive in 1987–1992 and 10 (20%) patients in 2000–2005, but this was not significant (P = 0.08). Reactions to non-fragrance consumer allergens (i.e. p-phenylenediamine and preservatives) had risen from 7 reactions (1987–1992) to 21 reactions in 13 individuals (2000–2005) (P < 0.001). Of these allergens, p-phenylenediamine was the most common (12%; P = 0.004).Conclusions: A significant rise in positive patch tests to non-fragrance consumer allergens, particularly p-phenylenediamine, was seen in CAD patients in 2000–2005. We speculate this alteration of allergen profile may be partly due to changes in exposure patterns.

Objectives: Various treatment options are available for the management of photosensitivity. The objective of this review is to evaluate the use of botanicals rich in antioxidants for photosensitivity reduction.
Design: Embase and Ovid/MEDLINE databases were searched for clinical studies evaluating antioxidants from botanical sources in the management of photosensitivity.
Results: Of 339 citations, 10 met the inclusion criteria. Four studies evaluated Polypodium leucotomos, two evaluated Camelia sinensis, while Hamamelis, Pistacia vera L., Citrus sinensis varieties Moro, Tarocco and Sanguinello, and Capparis spinosa were investigated in one study each. Five studies evaluated oral supplementation, four evaluated topical formulations, and one study evaluated both oral and topical antioxidants. Main results were summarized.
Conclusions: There is some evidence that antioxidants derived from botanical sources may be beneficial in reducing skin erythema and photosensitivity. However, the studies included in this review have methodological limitations and large scale randomized, placebo controlled trials are needed to further evaluate the efficacy and safety of botanical antioxidants in photosensitivity reduction.