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Like other methylated xanthine derivatives, pentoxifylline is a competitive nonselective phosphodiesterase inhibitor [20] which raises intracellular cAMP, activates PKA, inhibits TNF [21] [22] and leukotriene [23] synthesis, and reduces inflammation and innate immunity. [23]
7-Methylxanthine (7-MX), also known as heteroxanthine, is an active metabolite of caffeine (1,3,7-trimethylxanthine) and theobromine (3,7-dimethylxanthine). [ 1 ] [ 2 ] It is a non-selective antagonist of the adenosine receptors .
Involuntary extension of the "normal" leg occurs when flexing the contralateral leg against resistance. To perform the test, the examiner should hold one hand under the heel of the "normal" limb and ask the patient to flex the contralateral hip against resistance (while the patient is supine), asking the patient to keep the weak leg straight while raising it.
Methylxanthines activate histone deacetylases, promoting the deacetylation of histone and subsequent DNA folding. This inhibits the synthesis of pro-inflammatory factors that induce asthma attacks and exacerbations, achieving anti-inflammatory effects. [19] For asthma maintenance therapy, methylxanthines are taken orally. [2]
The characteristic signals, distinguishing theophylline from related methylxanthines, are approximately 3.23δ and 3.41δ, corresponding to the unique methylation possessed by theophylline. The remaining proton signal, at 8.01δ, corresponds to the proton on the imidazole ring, not transferred between the nitrogen.
Methylxanthines are chemical compounds which are derivatives of xanthine with one or more methyl groups, including: One methyl group: 1-Methylxanthine;
Respiratory arrest is a serious medical condition caused by apnea or respiratory dysfunction severe enough that it will not sustain the body (such as agonal breathing). Prolonged apnea refers to a patient who has stopped breathing for a long period of time. If the heart muscle contraction is intact, the condition is known as respiratory arrest.
The syndrome is often associated with obstructive sleep apnea (OSA), which causes periods of absent or reduced breathing in sleep, resulting in many partial awakenings during the night and sleepiness during the day. [1] The disease puts strain on the heart, which may lead to heart failure and leg swelling.