Ultraviolet light

About: Ultraviolet light is a research topic. Over the lifetime, 49494 publications have been published within this topic receiving 843151 citations.

Mycotoxins in botanicals and dried fruits: a review.

Abstract: Botanicals are used in many countries for medicinal and general health-promoting purposes. Numerous natural occurrences of mycotoxins in botanicals and dried fruits have been reported. Aflatoxins or ochratoxin A (OTA) have been found in botanicals such as ginseng, ginger, liquorice, turmeric, and kava-kava in the USA, Spain, Argentina, India, and some other countries, while fumonisins have been found in medicinal wild plants in South Africa and in herbal tea and medicinal plants in Turkey. Zearalenone was identified in ginseng root. Dried fruits can be contaminated with aflatoxins, OTA, kojic acid, and, occasionally, with patulin or zearalenone. One main area of concern is aflatoxins in dried figs; bright greenish yellow fluorescence under ultraviolet light is associated with aflatoxin contamination. OTA in dried vine fruits (raisins, sultanas, and currants) is another concern. There are also reports of aflatoxins in raisins and OTA in dried figs, apricots, dried plums (prunes), dates, and quince. Maximum permitted levels in the European Union include 4 microg kg(-1) for total aflatoxins in dried fruit intended for direct consumption and 10 microg kg(-1) for OTA in dried vine fruit. This review discusses the occurrence of mycotoxins in botanicals and dried fruits and analytical issues such as sampling, sample preparation, and methods for analysis. Fungal contamination of these products, the influence of sorting, storage, and processing, and prevention are also considered.

Coordinated induction and subsequent activity changes of two groups of metabolically interrelated enzymes. Light-induced synthesis of flavonoid glycosides in cell suspension cultures of Petroselinum hortense.

Abstract: The enzymes of the flavonoid glycoside pathway were specifically induced upon irradiation of a 10-day-old, dark-grown cell suspension culture of Petroselinum hortense Hoffm, with ultraviolet light. The curves for the activity changes of a first sequence of three enzymes (group I) revealed only small, but significant, differences. Sharp peaks in these enzyme activities were observed at about 17. 22, and 23 h after the onset of the irradiation. The apparent half-lives during the subsequent periods of decline ranged, in the same order, from about 10 to 15 and 17 h. No significant differences were found for the lag periods preceding the increases in the three enzyme activities. The possibility is discussed that the slight differences in the patterns of the light-induced activity changes are mainly due to different rates of degradation of the enzymes, suggesting an otherwise largely interpendent regulation. The patterns of the activity changes of four enzymes of the second sequence (group II) differed greatly from those observed for group I, but were again similar to one another. Thus, the two groups of enzymes appear to be regulated differently, despite their concomitant induction. A sigmoidal curve for the accumulation of the flavonoid glycosides was obtained upon the induction of the enzymes. This curve corresponded closely to that derived by integration of the curve for the activity changes of the first enzyme of group I. phenylalanine ammonia-lyase. It is concluded that this enzyme might be rate-limiting for the entire pathway.

Human immunodeficiency virus-associated eosinophilic folliculitis. A unique dermatosis associated with advanced human immunodeficiency virus infection.

Abstract: We studied 13 patients with human immunodeficiency virus (HIV) infection and a chronic pruritic folliculitis that was unresponsive to systemic treatment with bactericidal anti-staphylococcal antibiotics. The skin eruption was characterized by multiple urticarial follicular papules scattered on the trunk (100%), the head and neck (85%), and the proximal aspect of the extremities (62%). Absolute peripheral eosinophil counts were increased in six of 13 patients; a relative peripheral eosinophilia was present in 10 of 13 patients. Serum IgE levels were elevated in all seven patients tested (range, 88 to 9050 IU). Histopathologic features included a folliculitis with eosinophils. Pathogenic bacteria were not consistently found by routine bacterial skin cultures, cultures of skin biopsy specimens, or histopathologic evaluation. CD4 counts were decreased in all of the 12 patients tested (less than 300 cells per cubic millimeter) and were below 250 cells per cubic millimeter in 10 patients. A clinical response was noted to astemizole, to ultraviolet light in the B range, and to topical clobetasol propionate. These observations demonstrate that HIV-associated eosinophilic folliculitis is a unique HIV-related cutaneous disorder that is characterized by a culture-negative, chronic, pruritic folliculitis and a characteristic histopathologic picture. Of special importance, because it is associated with CD4 counts of less than 250 to 300 cells per cubic millimeter, eosinophilic folliculitis appears to be an important clinical marker of HIV infection and, particularly, of patients at increased risk of developing opportunistic infections. We suggest that the term eosinophilic pustular folliculitis (Ofuji's disease), previously used to describe this dermatosis in HIV-infected patients, should be discarded.