Ultraviolet light

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

Monoclonality in B cell lymphoma detected in paraffin wax embedded sections using the polymerase chain reaction.

Abstract: The polymerase chain reaction (PCR) was used to develop a simple technique for detecting monoclonality at the DNA level in B lymphocyte populations in formalin fixed, paraffin wax embedded material. Sections were dewaxed and dehydrated, and the DNA was extracted by boiling in water for 45 minutes. A semi-nested PCR was performed to amplify the V-D-J region of the immunoglobulin heavy chain gene. The product was electrophoresed and viewed under ultraviolet light after ethidium bromide staining. Specimens from 26 B cell lymphomas produced a monoclonal band in 24 cases and no amplification in two cases; monoclonality was specific for this disorder. Specimens from seven T cell lymphomas produced no amplification; specimens from nine reactive nodes produced a broad smear of polyclonal material; and specimens from 12 cases of carcinoma produced either no amplification or polyclonal material. As detection of monoclonality is strongly suggestive of neoplastic disease, this technique is likely to be of value in routine diagnosis, because of its speed, simplicity, and applicability to fixed, embedded material.

Immunotoxicology and immunopharmacology

Abstract: The second edition of this text has been revised and refocused to reflect the transformation of immunotoxicology from a subdiscipline of toxicology to an independent area of research that can best be described as "environmental immunology" New chapters discuss the role of immune mediators in liver, lung, and skin toxicity, in regulating chemical- metabolizing enzymes, and in the immunosuppression produced by ultraviolet light More emphasis is placed on the clinical consequences of immunotoxicity, as well as the interpretation of experimental data for predicting, human health risk; The second edition is divided into three major sections: immunosuppression, autoimmunity, and hypersensitivity This new organization of the text allows for a more thorough treatment of these phenomena, with greater attention to test methods, theoretical considerations, and clinical implications The book includes many chapters on specific environmental agents, therapeutic drugs, biological agents, and drugs of abuse, as well as on immune-mediated toxicity in specific organ systems

Potential involvement of free radical reactions in ultraviolet light‐mediated cutaneous damage*

Abstract: Free radicals are chemical species characterized by an odd number of orbital electrons or by pairs of electrons of similar directional spin isolated singly in separate orbitals. Consequently most of these agents are highly reactive and usually exhibit an extremely short half-life, although due to steric and resonance effects some exceptions occur. Some radicals and their precursors, such as the diradical O2 which exists in the triplet state, represent a critical and essential element of normal metabolism of aerobic organisms where, under normal circumstances, controlled reduction of reactive oxygen species occurs via the cytochrome oxidase or cytochrome P-450 mixed function monooxygenase systems. In addition to reactive oxygen species, organisms may be subjected to a wide-range of other free radicals or their precursors, including those of both exogenous and endogenous origin. Elaborate defense mechanisms have evolved to avoid cellular damage from these highly reactive species. Enzymes, such as the superoxide dismutase, the glutathione peroxidase/reductase system, and catalase; interactions with conjugated diene systems such as those found in melanins, carotenoids, and tocopherols; and direct reduction by sulphydryl compounds, phenols, and purines represent but a few of these natural defense systems. Despite a strong rationale for considering free radicals as pathologic agents, progress in implicating these agents, or their reactions, in pathologic processes has been arduous. The fore-most hurdle to providing definitive evidence for free radical involvement rests with the highly transient nature of these species, hardly reaching measurable levels in vivo and thereby making rigorous testing of the hypothesis extremely difficult. Indeed, free radical damage has been studied, for the most part, by indirect means–usually by measurement of known free radical reaction intermediates and products from which free radical involvement is implied. Nevertheless, free radical formation has been shown to occur in UV-irradiated skin and a considerable body of circumstantial evidence has been amassed that strongly infers that these agents, or reactions initiated by them, are responsible for at least some of the deleterious effects of UV upon skin.

The relative cytotoxicity of (6-4) photoproducts and cyclobutane dimers in mammalian cells.

Abstract: — The significance of the pyrimidine(6-4)pyrimidone photoproduct in mammalian cell killing is considered. Photochemical data indicate that the(6–4) photoproduct is induced at a substantial frequency compared to the cyclobutane dimer and that the action spectra for the induction of both lesions are equivalent. The repair of(6–4) photoproducts in various normal and UV-hypcrsensitive mammalian cell lines, including several recently derived somatic cell hybrids and transformants, is presented. The sensitivity of these cells to ultraviolet irradiation correlates better with the capacity to repair(6–4) photoproducts than cyclobutane dimers. These data are used to support that idea that the(6–4) photoproduct is one of the major cytotoxic lesions induced in DNA by ultraviolet light.

Attraction of kestrels to vole scent marks visible in ultraviolet light

Abstract: IN northern Europe, broad four-year oscillations in small rodent and raptor populations are synchronous over hundreds of square kilometers1–6. Crashes in vole populations can induce wide emigration (> 1,000 km) of their predators7 –9, but almost nothing is known about how predators rapidly detect areas of vole abundance. Here we report on laboratory and field experiments on voles (Microtus agrestis) and kestrels (Falco tinnunculus). Voles mark their runaways with urine and faeces, which are visible in ultraviolet light. Wild kestrels brought into captivity were able to detect vole scent marks in ultraviolet light but not in visible light. In the field, kestrels hunted preferentially near experimental nest-boxes where artificial trails were treated with vole urine and faeces. We suggest that kestrels flying over an area can see and use vole scent marks to assess vole numbers. This ability would enable kestrels to 'screen' large areas in a relatively short time. Our results provide a novel explanation for how raptors detect patches of high vole densities without prior knowledge of local food resources.