Medical hypotheses
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Oxidative stress underlies postoperative atrial fibrillation and electrophysiological remodelling associated with rapid atrial pacing. An increasing body of evidence indicates that the formation of reactive oxygen species (ROS) released following extracorporeal circulation are involved in the structural and functional myocardial impairment derived from the ischemia-reperfusion cycle. ROS behave as intracellular messengers mediating pathological processes, such as inflammation, apoptosis and necrosis, thereby participating in the pathophysiology of atrial fibrillation. ⋯ In turn, experimental studies have revealed that non-enzymatic antioxidants produce a significant functional amelioration in cardiomyocytes subjected to an oxidative challenge. Moreover, clinical studies with patients scheduled for primary coronary artery bypass graft surgery had a reduced incidence of postoperative atrial fibrillation. We present the hypothesis of non-hypoxic preconditioning based on the association of pretreatment with n-3 polyunsaturated fatty acids followed by ascorbate plus alpha-tocoferol supplementation diminishes the incidence of postoperative atrial fibrillation in patients subjected to cardiac surgery with extracorporeal circulation.
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Hematopoietic stem cells transplantation has been wildly used in clinical settings and has shown exciting results in treating a wide variety of diseases. However, the relative small number of hematopoietic stem cells in bone marrow, even lower in peripheral or umbilical cord blood limits its clinical utility. There are several protocols, which have been developed to expand hematopoietic stem cells to reach clinical goal. ⋯ And the recombinant fusion proteins could be used in expanding hematopoietic stem cells. Meanwhile, Cdx4 fusion proteins would be more efficient than other methods that had been developed for it can up-regulate a cocktail of hox genes, which has been proved to be capable of amplifying hematopoietic stem cells. It would provide us an alternative protocol to amplify hematopoietic stem cells if the hypothesis proved to be practical.
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Amniotic fluid embolism, a rare, sudden and often fatal illness of pregnancy may not be a true embolic event resulting from the physical obstruction of the pulmonary vasculature. The high degree of variability in symptoms, the lack of characteristic findings on radiological exam, the absence of a dose-response effect on symptoms, and the occasional occurrence of coagulopathies are not entirely consistent with a physical block to the circulation as the main mechanism of disease. Alternatively, it might be the result of complement activation initiated by fetal antigen leaking into the maternal circulation. ⋯ Direct measurement of serum complement as well as serum tryptase and urinary histamine are readily obtained tests in community hospitals as well as tertiary care hospitals. If the hypothesis proves true, this investigation may be of profound importance to understanding immune tolerance. Rather, than asking why one pregnant woman in 20,000 develops a violent immune reaction to the fetus, a better question is why do not all pregnant women reject the fetus which is a large collection of foreign antigens?
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The mechanisms responsible for symptom expression in fibromyalgia (FM) are complex. The most consistently detected objective abnormalities in FM involve pain-processing systems. Up to recently, central nervous system was a primary focus of investigations in FM. ⋯ This paper suggests that patients with FM represent a state of the dysfunction of descending, antinociceptive pathways and low hypothalamic-pituitary-adrenal function. This state is further proposed to result in many skin biopsy findings associated with the disorder, including increased N-methyl-d-aspartate receptors subtype 2D expression, neurogenic inflammation and characteristic electron microscopic findings. Future direction of research would be identification of specific laboratory markers such as skin biopsy for diagnostic and clinical evaluation purposes in FM.
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The four science Nobel prizes (physics, chemistry, medicine/physiology and economics) have performed extremely well as a method of recognizing the highest level of achievement. The prizes exist primarily to honour individuals but also have a very important function in science generally. In particular, the institutions and nations which have educated, nurtured or supported many Nobel laureates can be identified as elite in world science. ⋯ I therefore suggest that the maximum of three laureates per year should always be awarded in the categories of physics, chemistry and economics, even when these prizes are for diverse and un-related achievements; that the number of laureates in the 'biology' category of physiology or medicine should be increased to six or preferably nine per year; and that two new Prize categories should be introduced to recognize achievements in mathematics and computing science. Together, these measures could increase the science laureates from a maximum of 12 to a minimum of 24, and increase the range of scientific coverage. In future, the Nobel committee should also officially allocate proportionate credit to institutions for each laureate, and a historical task force could also award institutional credit for past prizes.