Medical hypotheses
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Reported interstitial pressures range from -8 to +6 mm Hg in different tissues and from <-20 mm Hg in burned tissue or more than +30 mm Hg in tumors. We have tried to link interstitial pressure to the here proposed cyclical changes in the fluid transport across the capillary wall. In the presented model interstitial pressure is considered as an average of pressures in numerous pericapillary spaces. ⋯ Positive interstitial pressures observed in some organs might develop if open periods are longer than the closed periods. High interstitial colloid pressure in lungs makes both perfused and unperfused capillaries absorptive, resulting in more negative values of lung interstitial pressure. The same model is used to explain interstitial pressure values in tumors, burned tissue and intestinal villi.
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Review
Chronic fatigue syndrome: neurological findings may be related to blood--brain barrier permeability.
Despite volumes of international research, the etiology of chronic fatigue syndrome (CFS) remains elusive. There is, however, considerable evidence that CFS is a disorder involving the central nervous system (CNS). It is our hypothesis that altered permeability of the blood-brain barrier (BBB) may contribute to ongoing signs and symptoms found in CFS. ⋯ The factors which can compromise the normal BBBP in CFS include viruses, cytokines, 5-hydroxytryptamine, peroxynitrite, nitric oxide, stress, glutathione depletion, essential fatty acid deficiency, and N-methyl-D-aspartate overactivity. It is possible that breakdown of normal BBBP leads to CNS cellular dysfunction and disruptions of neuronal transmission in CFS. Abnormal changes in BBBP have been linked to a number of disorders involving the CNS; based on review of the literature we conclude that the BBB integrity in CFS warrants investigation.