Seasons Last Rose
Photograph - Photo
blooming dog.rose in late septembre Canon 5D mk III
Digitalis toxicity (Digitalis intoxication) results from an overdose of digitalis and causes anorexia, nausea, vomiting and diarrhoea, as well as sometimes resulting in xanthopsia (jaundiced or yellow vision) and the appearance of blurred outlines (halos). Bradycardia also occurs. Because a frequent side effect of digitalis is reduction of appetite, some individuals have used the drug as a weight-loss aid.
Digitalis is an example of a drug derived from a plant that was formerly used by folklorists and herbalists; herbalists have largely abandoned its use because of its narrow therapeutic index and the difficulty of determining the amount of active drug in herbal preparations. Once the usefulness of digitalis in regulating the human pulse was understood, it was employed for a variety of purposes, including the treatment of epilepsy and other seizure disorders, which are now considered to be inappropriate treatments.
Digitalis purpurea drawings by Franz K�hler
Depending on the species, the digitalis plant may contain several deadly physiological and chemically related cardiac and steroidal glycosides. Thus, the digitalis plants have earned several, more sinister, names: dead man�s bells and witch's gloves.
The entire plant is toxic (including the roots and seeds). Mortality is rare, but case reports do exist. Most plant exposures occur in children younger than six years and are usually unintentional and without associated significant toxicity. More serious toxicity occurs with intentional ingestions by adolescents and adults. Early symptoms of ingestion include nausea, vomiting, diarrhoea, abdominal pain, wild hallucinations, delirium, and severe headache. Depending on the severity of the toxicosis, the victim may later suffer irregular and slow pulse, tremors, various cerebral disturbances, especially of a visual nature (unusual colour visions (see xanthopsia) with objects appearing yellowish to green, and blue halos around lights), convulsions, and deadly disturbances of the heart. For a case description, see the paper by Lacassie. Vincent van Gogh's "Yellow Period" may have been influenced by digitalis therapy which, at the time, was thought to control seizures. As noted above, other oculotoxic effects of digitalis include generalized blurry vision, as well as seeing a "halo" around each point of light.
In some instances, people have confused digitalis with the relatively harmless comfrey (Symphytum ) plant, which is often brewed into a tea, with fatal consequences. Other fatal accidents involve children drinking the water in a vase containing digitalis plants. Drying does not reduce the toxicity of the plant. The plant is toxic to animals, including all classes of livestock and poultry, as well as felines and canines.
Digitalis poisoning can cause heart block and either bradycardia (decreased heart rate) or tachycardia (increased heart rate), depending on the dose and the condition of one's heart. Notably, the electric cardioversion (to "shock" the heart) is generally not indicated in ventricular fibrillation in digitalis toxicity, as it can increase the dysrhythmia. Also, the classic drug of choice for ventricular fibrillation in emergency setting, amiodarone, can worsen the dysrhythmia caused by digitalis, therefore, the second-choice drug lidocaine is more commonly used.
The plant is high in certain antioxidants. The fruit is noted for its high vitamin C level and is used to make syrup, tea and marmalade. It has been grown or encouraged in the wild for the production of vitamin C, from its fruit (often as rose-hip syrup), especially during conditions of scarcity or during wartime. The species has also been introduced to other temperate latitudes. During World War II in the United States Rosa canina was planted in victory gardens, and can still be found growing throughout the United States, including roadsides, and in wet, sandy areas up and down coastlines. In Bulgaria, where it grows in abundance, the hips are used to make a sweet wine, as well as tea. In the traditional Austrian medicine Rosa canina fruits have been used internally as tea for treatment of viral infections and disorders of the kidneys and urinary tract.
Forms of this plant are sometimes used as stocks for the grafting or budding of cultivated varieties. The wild plant is planted as a nurse or cover crop, or stabilising plant in land reclamation and specialised landscaping schemes.
The dog roses, the Canina section of the genus Rosa (20-30 species and subspecies, which occur mostly in Northern and Central Europe), have an unusual kind of meiosis that is sometimes called "permanent odd polyploidy" although it can occur with even polyploidy (e.g. in tetraploids or hexaploids). Regardless of ploidy level, only seven bivalents are formed leaving the other chromosomes as univalents. Univalents are included in egg cells, but not in pollen. Dogroses are most commonly pentaploid, i.e. five times the base number of seven chromosomes for the genus Rosa, but may be tetraploid or hexaploid as well.
he botanical name is derived from the common names 'dog rose' or similar in several European languages, including classical Latin and ancient (Hellenistic period) Greek.
It is sometimes considered that the word 'dog' has a disparaging meaning in this context, indicating 'worthless' (by comparison with cultivated garden roses) (Vedel & Lange 1960). However it also known that it was used in the eighteenth and nineteenth centuries to treat the bite of rabid dogs, hence the name "dog rose" may result from this (though it seems just as plausible that the name gave rise to the treatment).
Other old folk names include dogberry and witches' briar.
September 27th, 2013
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