What causes photosensitization?
What causes photosensitization?
Photosensitization is a condition caused by the accumulation of a photodynamic agent in the skin that sensitizes it to ultraviolet radiation (Fowler 1993). Exposure of nonpigmented skin to UV radiation (e.g., the sun) results in dermatonecrosis.
What happens in photosensitization?
In photosensitization, unstable, high-energy molecules are formed when photons react with a photodynamic agent. These high-energy molecules initiate reactions with substrate molecules of the skin, causing the release of free radicals that in turn result in increased permeability of outer cell and lysosomal membranes.
How is Photosensitisation treated?
Secondary photosensitisation occurs as a result of liver damage. Prompt treatment by removing stock from the source of the toxin, keeping them out of direct sunlight and providing nursing care will normally result in recovery.
What are the types of photosensitization?
Three types of photosensitization occur: primary, secondary or hepatogenous, and aberrant. Primary photosensitization is related to plant pigments or drugs such as phenothiazine, sulfonamides, or tetracyclines.
What is Photosensitization give example?
In a typical photosensitized reaction, as in the photodecomposition of ethylene to acetylene and hydrogen, a mixture of mercury vapour and ethylene is irradiated with a mercury lamp. In colliding with ethylene molecules, the mercury atoms transfer the energy and are in turn deactivated to their initial energy state.
How is cattle Photosensitization treated?
How do you treat photosensitisation? In the acute stages affected animals should have access to shade during the whole of daylight hours e.g. under trees or with access to farm buildings. Anti-inflammatory and anti-histamine injections may relieve irritation and reduce self-trauma from rubbing/kicking affected area.
What causes photosensitivity in sheep?
Over the past 10 years, isolated cases of photosensitisation have occurred in sheep grazing both Casbah and Mauro biserrula throughout the wheatbelt. Photosensitivity is a state of heightened sensitivity to sunlight caused by the presence of photodynamic chemicals in the skin, cornea and mucous membranes.
What causes photosensitization in cattle?
“Three factors contribute to the development of photosensitization: presence of a photo-activating substance in the skin circulation, exposure to light and lack of skin pigment [allowing absorption of UV light],” he says.
What is equine Photosensitization?
Photosensitization is a condition in which skin becomes overly sensitive to ultraviolet light (sunlight). This condition is not sunburn, although the difference can be difficult to distinguish.
What causes Photosensitisation in sheep?
Photosensitivity is a state of heightened sensitivity to sunlight caused by the presence of photodynamic chemicals in the skin, cornea and mucous membranes. Photosensitivity may result in photosensitisation, which is the dermatitis and conjunctivitis produced in a sensitised animal after exposure to sunlight.
What is Photosensitization in food?
Photosensitization, also known as photodynamic treatment, has recently gained interest in food research with reported promising results in food systems including significant inactivation of planktonic cells and biofilm of Vibrio parahaemolyticus (Chen et al., 2020), and effective decontamination of pieces of beef, pork …
What is the purpose of photosensitizer?
Photosensitizers are molecules that can be activated by light in order to generate ROS that can damage cell structures from microorganisms or from diseased mammalian cells leading to cell death.
What causes photosensitisation in sheep in the UK?
Cases of photosensitisation occur either as a primary condition or secondary to liver damage. Most cases of photosensitisation seen in the UK follow the movement of sheep from poor to lush green pasture such as silage aftermaths, and are associated with failure to adapt to increased amounts of chlorophyll.
What are the signs of photosensitisation in cattle?
• In cattle, skin damage also occurs along the back and on the sides of the udder that are exposed to the sun, with damage limited to the white areas and sparing of the coloured areas being characteristic. Signs of photosensitisation • The skin becomes red, weepy and swollen.
What kind of animals are affected by photosensitization?
Photosensitization occurs worldwide and can affect any species but is most commonly seen in cattle, sheep, goats, and horses. Primary photosensitization occurs when the photodynamic agent is either ingested, injected, or absorbed through the skin.
Why did my Ewe get photosensitisation after grazing wheat?
This ewe is suffering from photosensitisation after grazing wheat. Pre-existing liver damage from ingestion of Paterson’s curse may have been the underlying cause in this case. Notice the damaged and dying skin around the eye, down the face, on the nose, lips and ear. The ear is swollen and droopy.
