|
Visudyne
Verteporfin (trade name Visudyne), a benzoporphyrin derivative, is a medication used as a photosensitizer for photodynamic therapy to eliminate the abnormal blood vessels in the eye associated with conditions such as the wet form of macular degeneration. Verteporfin accumulates in these abnormal blood vessels and, when stimulated by nonthermal red light with a wavelength of 689 nm in the presence of oxygen, produces highly reactive short-lived singlet oxygen and other reactive oxygen radicals, resulting in local damage to the endothelium and blockage of the vessels.Verteporfin Verteporfin is also used off-label for the treatment of central serous retinopathy. Administration Verteporfin is usually injected intravenously into the largest arm vein. It is injected at a dose of 6 mg/m2 and light-activated. It is usually given 15 minutes before laser treatment. This dose can be repeated 4 times per year. Contraindications Porphyria : Patients with porphyria should not rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photodynamic Therapy
Photodynamic therapy (PDT) is a form of phototherapy involving light and a photosensitizing chemical substance used in conjunction with molecular oxygen to elicit cell death ( phototoxicity). PDT is used in treating acne, wet age-related macular degeneration, psoriasis, and herpes. It is used to treat malignant cancers, including head and neck, lung, bladder and skin. Advantages lessen the need for delicate surgery and lengthy recuperation and minimal formation of scar tissue and disfigurement. A side effect is the associated photosensitisation of skin tissue. Basics PDT applications involve three components: a photosensitizer, a light source and tissue oxygen. The wavelength of the light source needs to be appropriate for exciting the photosensitizer to produce radicals and/or reactive oxygen species. These are free radicals (Type I) generated through electron abstraction or transfer from a substrate molecule and highly reactive state of oxygen known as singlet oxygen ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intravenous Therapy
Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrients for those who cannot, or will not—due to reduced mental states or otherwise—consume food or water per os, by mouth. It may also be used to administer pharmaceutical drug, medications or other medical therapy such as blood transfusion, blood products or electrolytes to correct electrolyte imbalances. Attempts at providing intravenous therapy have been recorded as early as the 1400s, but the practice did not become widespread until the 1900s after the development of techniques for safe, effective use. The intravenous route is the fastest way to deliver medications and fluid replacement throughout the body as they are introduced directly into the circulatory system and thus quickly distributed. For this reason, the intravenous route ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Serous Retinopathy
Central serous chorioretinopathy (CSC or CSCR), also known as central serous retinopathy (CSR), is an eye disease that causes visual impairment, often temporary, usually in one eye. When the disorder is active it is characterized by leakage of fluid under the retina that has a propensity to accumulate under the central macula. This results in blurred or distorted vision ( metamorphopsia). A blurred or gray spot in the central visual field is common when the retina is detached. Reduced visual acuity may persist after the fluid has disappeared. The disease is considered of unknown cause. It mostly affects white males in the age group 20 to 50 (male:female ratio 6:1) and occasionally other groups. The condition is believed to be exacerbated by stress or corticosteroid use. Pathophysiology Recently, central serous chorioretinopathy has been understood to be part of the pachychoroid spectrum. In pachychoroid spectrum disorders, of which CSR represents stage II, the choroid, the h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosensitizing Agents
Photosensitizers are light absorbers that alter the course of a photochemical reaction. They usually are catalysts. They can function by many mechanisms; sometimes they abstract an electron from the substrate, and sometimes they abstract a hydrogen atom from the substrate. At the end of this process, the photosensitizer returns to its ground state, where it remains chemically intact, poised to absorb more light. One branch of chemistry which frequently utilizes photosensitizers is polymer chemistry, using photosensitizers in reactions such as photopolymerization, photocrosslinking, and photodegradation. Photosensitizers are also used to generate prolonged excited electronic states in organic molecules with uses in photocatalysis, photon upconversion and photodynamic therapy. Generally, photosensitizers absorb electromagnetic radiation consisting of infrared radiation, visible light radiation, and ultraviolet radiation and transfer absorbed energy into neighboring molecules. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome P450
Cytochromes P450 (P450s or CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that mostly, but not exclusively, function as monooxygenases. However, they are not omnipresent; for example, they have not been found in ''Escherichia coli''. In mammals, these enzymes oxidize steroids, fatty acids, xenobiotics, and participate in many biosyntheses. By hydroxylation, CYP450 enzymes convert xenobiotics into hydrophilic derivatives, which are more readily excreted. P450s are, in general, the terminal oxidase enzymes in electron transfer chains, broadly categorized as P450-containing systems. The term "P450" is derived from the spectrophotometry, spectrophotometric peak at the wavelength of the absorption spectroscopy, absorption maximum of the enzyme (450 nanometre, nm) when it is in the redox, reduced state and complexed with carbon monoxide. Most P450s require a protein partner to deliver one or more electrons to reduc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanacetum Parthenium
''Tanacetum parthenium'', known as feverfew, is a flowering plant in the daisy family, Asteraceae. It may be grown as an ornament, and may be identified by its synonyms, ''Chrysanthemum parthenium'' and ''Pyrethrum parthenium''. Having its origin in the Balkans region, it is now distributed worldwide. Although long used in traditional medicine, there is no clinical evidence that it has any therapeutic effects. Description The plant is a herbaceous perennial that grows into a small bush, up to high, with pungently-scented leaves. The leaves are light yellowish green, variously pinnatifid. The conspicuous daisy-like flowers are up to across, borne in lax corymbs. The outer, ray florets have white ligules and the inner, disc florets are yellow and tubular. It spreads rapidly by seed, and will cover a wide area after a few years. The plant produces achene fruit, and grows in stony slopes and river beds. Location and cultivation Feverfew is native to Eurasia, specifical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytotoxicity
Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are toxic metals, toxic chemicals, microbe neurotoxins, radiation particles and even specific neurotransmitters when the system is out of balance. Also some types of drugs, e.g alcohol, and some venom, e.g. from the puff adder (''Bitis arietans'') or brown recluse spider (''Loxosceles reclusa'') are toxic to cells. Cell physiology Treating cells with the cytotoxic compound can result in a variety of prognoses. The cells may undergo necrosis, in which they lose membrane integrity and die rapidly as a result of cell lysis. The cells can stop actively growing and dividing (a decrease in cell viability), or the cells can activate a genetic program of controlled cell death (apoptosis). Cells undergoing necrosis typically exhibit rapid swelling, lose membrane integrity, shut down metabolism, and release their contents into the environment. Cells that undergo rapid necrosis in vitro do not have sufficient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosensitivity
Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicity. The photosensitive ganglion cells in the mammalian eye are a separate class of light-detecting cells from the photoreceptor cells that function in vision. Skin reactions Human medicine Sensitivity of the skin to a light source can take various forms. People with particular skin types are more sensitive to sunburn. Particular medications make the skin more sensitive to sunlight; these include most of the tetracycline antibiotics, heart drugs amiodarone, and sulfonamides. Some dietary supplements, such as St. John's Wort, include photosensitivity as a possible side effect. Particular conditions lead to increased light sensitivity. Patients with systemic lupus erythematosus experience skin symptoms after sunlight exposure; some typ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypersensitivity
Hypersensitivity (also called hypersensitivity reaction or intolerance) is an abnormal physiological condition in which there is an undesirable and adverse immune response to an antigen. It is an abnormality in the immune system that causes Immune disorder, immune diseases including allergies and autoimmunity. It is caused by many types of particles and substances from the external environment or from within the body that are recognized by the immune cells as antigens. The immune reactions are usually referred to as an over-reaction of the immune system and they are often damaging and uncomfortable. In 1963, Philip George Houthem Gell and Robin Coombs introduced a systematic classification of the different types of hypersensitivity based on the types of antigens and immune responses involved. According to this system, known as the #Gell and Coombs classification, Gell and Coombs classification or Gell-Coombs's classification, there are four types of hypersensitivity, namely: Typ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porphyria
Porphyria ( or ) is a group of disorders in which substances called porphyrins build up in the body, adversely affecting the skin or nervous system. The types that affect the nervous system are also known as Porphyria#Acute porphyrias, acute porphyria, as symptoms are rapid in onset and short in duration. Symptoms of an attack include abdominal pain, chest pain, vomiting, confusion, constipation, fever, hypertension, high blood pressure, and tachycardia, high heart rate. The attacks usually last for days to weeks. Complications may include paralysis, hyponatraemia, low blood sodium levels, and seizures. Attacks may be triggered by Alcohol (drug), alcohol, smoking, hormonal changes, fasting, stress, or certain medications. If the skin is affected, blisters or itching may occur with sunlight exposure. Most types of porphyria are inherited from one or both of a person's parents and are due to a mutation in one of the genes that make heme. They may be inherited in an autosomal dom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intravenous Therapy
Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrients for those who cannot, or will not—due to reduced mental states or otherwise—consume food or water per os, by mouth. It may also be used to administer pharmaceutical drug, medications or other medical therapy such as blood transfusion, blood products or electrolytes to correct electrolyte imbalances. Attempts at providing intravenous therapy have been recorded as early as the 1400s, but the practice did not become widespread until the 1900s after the development of techniques for safe, effective use. The intravenous route is the fastest way to deliver medications and fluid replacement throughout the body as they are introduced directly into the circulatory system and thus quickly distributed. For this reason, the intravenous route ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endothelium
The endothelium (: endothelia) is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel wall. Endothelial cells in direct contact with blood are called vascular endothelial cells whereas those in direct contact with lymph are known as lymphatic endothelial cells. Vascular endothelial cells line the entire circulatory system, from the heart to the smallest capillaries. These cells have unique functions that include fluid filtration, such as in the glomerulus of the kidney, blood vessel tone, hemostasis, neutrophil recruitment, and hormone trafficking. Endothelium of the interior surfaces of the heart chambers is called endocardium. An impaired function can lead to serious health issues throughout the body. Structure The endothelium is a thin layer of single flat (squamous) cells that line the inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
