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Specialized Circulations in Susceptible Tissues
Published in Wilmer W Nichols, Michael F O'Rourke, Elazer R Edelman, Charalambos Vlachopoulos, McDonald's Blood Flow in Arteries, 2022
The role of these different methods is still not clear. There is justifiable doubt about the need for adenosine and concern over its side effects. It is, of course, desirable to measure the pressure gradient and flow over that period of diastole when flow occurs (i.e. “instantaneously”) with pressure. It is helpful to have this identified automatically with in-built software as in the SphygmoCor report for other indices. There is uncertainty over the theoretic basis for iFR as being valid (Westerhof et al., 2015; Kyriacou et al., 2012; Smolich and Mynard, 2016). Certainly it makes more sense to measure coronary artery pressure gradient over that period in diastole when the coronary arteries are perfused, but the pressure during diastole does represent a wave and is so described throughout this book. Concerns are summarized in Figures 14.22, 14.23 and 14.24. Results from measuring the instantaneous gradient alone may be sufficient to provide functional information (Alfonso and Rivero, 2018). Outcome has not been better with either CFR or iFR in emergency or elective procedures as an addition to angiography alone (Escaned et al., 2018; Shah et al., 2018) (Figure 14.22). Comparisons of the two commercially available methods have been on the basis of “inferiority”. Such studies continue with strong industry support.
Medicine
Published in Seema Khan, Get Through, 2020
Adenosine is absolutely contraindicated in asthma. β Blockers are also contraindicated but, in rare instances where there is no alternative, a cardioselective β blocker may be prescribed with extreme caution under specialist supervision.
Sleep-Promoting Substance (SPS) and Nucleosides
Published in Shojiro Inoué, Biology of Sleep Substances, 2020
Adenosine (see Figure 17) is a naturally occurring purine nucleoside. Its actions as a potent neuromodulator in the central nervous system include sedative, anticonvulsant, hypnogenic, ataxic, and antinociceptive properties.60 In addition, adenosine exerts an inhibitory action on neuronal firing activity45 and interacts with other neurotransmitters, neuromodulators, and hormones. For example, its depressant activity on the firing of rat cerebral cortical neurons is potentiated by progesterone.61 Adenosine at very large doses (1 to 100 mg/kg s.c. or i.p.) causes hypothermia in rats.62 Thus, adenosine seems to play a considerably general role in regulating the degree of “alertness” in the central nervous system.60
An Evaluation of Prehospital Adenosine Use
Published in Prehospital Emergency Care, 2023
Alexander R. Nelson, David C. Cone, Ani Aydin, Kevin Burns, Mark X. Cicero, Katherine Couturier, Mark Rollins, Matthew Shapiro, Daniel Joseph
Adenosine is not indicated for atrial fibrillation with rapid ventricular response. There may be a diagnostic benefit of adenosine use to slow the heart rate and allow an interpretation of the underlying rhythm. However, some reviewed cases that identified an underlying non-SVT rhythm had continued attempts at cardioversion with adenosine. While there is an inherent selection bias as the data were obtained by searching for uses of adenosine rather than for all cases of atrial fibrillation, there were instances of paramedic documented histories of atrial fibrillation or narrative descriptions of wide or irregular rhythms, with adenosine nevertheless chosen as the first-line medication rather than rate control medication or electrical cardioversion. There may be an opportunity for continued focused education regarding the diagnosis and management of regular and irregular tachyarrhythmias by prehospital clinicians.
Modulatory effects of stonebreaker (Phyllanthus amarus) and bitter gourd (Momordica charantia) on enzymes linked with cardiac function in heart tissue of doxorubicin-stressed rats
Published in Drug and Chemical Toxicology, 2022
Jamiyu A. Saliu, Sunday Idowu Oyeleye, Tosin A. Olasehinde, Ganiyu Oboh
Disruption in purinergic signaling is linked with many cardiac problems (Burnstock 2017a, 2017b). ADA regulates the levels of adenosine and trigger its breakdown to inosine. The significant increase in ADA activity observed in rats stressed with DOX suggests depletion of adenosine and impairment in purinergic metabolism in the cardiovascular system. This result correlates with the report of Akinyemi et al. (2016), which revealed high ADA activity in L-NAME –induced hypertensive rats. Adenosine has been identified as a cardioprotective agent against heart related conditions (Greene et al.2016). It plays a major role in the regulation of inflammatory responses, which are triggered by pathological events associated with ischemia (Burnstock et al. 2017a). However, treatment with PA and MC caused a significant reduction in ADA activity in pretreated DOX rats, which in turn could reduce rapid degradation of adenosine, thereby, improving its concentration and function in cardiac tissue. These findings further suggest that the studied plant leaves could mitigate cardiovascular complications associated with impaired adenosine metabolism caused by DOX-induced oxidative stress, and these could be linked with the synergistic effects of the phenolic acids and flavonoids present in the plants.
Caffeine attenuates seizure and brain mitochondrial disruption induced by Tramadol: the role of adenosinergic pathway
Published in Drug and Chemical Toxicology, 2021
Mahedeh Samadi, Fatemeh Shaki, Behnaz Bameri, Marjan Fallah, Nematollah Ahangar, Hamidreza Mohammadi
Adenosine is present in all cells and has controlling role in every tissue and organ function. Adenosine has a crucial role in regulation of pathophysiological and modulation of normal physiological processes. Adenosine has four receptors (A1, A2a, A2b, and A3) expressed in myocardial and vascular cells and coupled to G proteins to trigger a range of responses (generally, but not always beneficial) (Boison 2015). Adenosine receptors are involved in many physiological processes such as seizure susceptibility, neuroprotection, and regulation of pain perception or sleep induction (Peart and Headrick 2007, Listos et al.2010). Endogenous adenosine has a neuromodulator and anticonvulsant activities in the mammalian brain. Furthermore, the adenosine action is mediated in the Central Nervous System (CNS) mainly through interaction with adenosine A1 and A2 receptor subtypes (Adami et al.1995, Peart and Headrick 2007). The evidences show that adenosine has inhibitory tone and reduces influx of Ca2+ and opens potassium channels in presynaptic and may act as endogenous anticonvulsant in the brain. Moreover, release of excitatory amino acids is inhibited by adenosine (A1) receptor (Boison 2015).