Brain water content

Experimentally, the BBB disruption can be assessed by the administration of dyes (e.g., Evans blue, Fluorescein) or radioactive tracers (e.g., [14C] sucrose) and visualization or measurement of their distribution in the brain parenchyma on tissue sections (Fig. 8.1). To estimate brain water content, the weight of a brain is determined with the wet-and-dry-weight method , i.e., weighing the tissue speci-... 

Neuropsychiatric symptoms are less frequent with subcutaneous aldesleukin (10). No predictive or predisposing factors have been clearly identified. Whether a direct effect of aldesleukin on neuronal tissues, an increased vascular brain permeability with a subsequent increased brain water content, or an aldesleukin-induced release of neuroendocrine hormones (beta-endorphin, ACTH, or cortisol), accounted for these effects, is unknown. A possible immune-mediated cerebral vasculitis has also been reported in one patient (SEDA-20, 334). 

Show brain water content (cerebrospinal fluid) and proton density... 

Experimental evidence indicates that COX modulates BBB permeability in neuroinflammatory conditions, ischemia, and hemorrhage. The COX inhibitor, KBT-3022, prevented brain edema induced by bilateral carotid occlusion and recirculation in gerbils (Yamamoto et al., 1996). In the collagenase model of intracerebral hemorrhage, the brain water content of rats treated with the COX-2 inhibitor, celecoxib, decreased both in lesioned and nonlesioned hemispheres in a dose-dependent manner, which was accompanied with reduced perihematomal cell death (Chu et al., 2004). Delayed damage to the BBB and vasogenic edema, which follow ischemic stroke, were significantly diminished by administration of... 

Uremia is characterized by retention in the blood of urea, phosphates, proteins, amines and a number of poorly defined low-molecular-weight compounds. Despite acidemia, the pH of brain, muscle and CSF are normal in humans with renal failure. Whereas brain water, K+ and Mg2+ content are normal, Al3+ and Ca2+ concentrations are significantly increased [14]. 

TThe catabolic production of ammonia poses a serious biochemical problem, because ammonia is very toxic. The molecular basis for this toxicity is not entirely understood. The terminal stages of ammonia intoxication in humans are characterized by onset of a comatose state accompanied by cerebral edema (an increase in the brain s water content) and increased cranial pressure, so research and speculation on ammonia toxicity have focused on this tissue. Speculation centers on a potential depletion of ATP in brain cells. 

The lipid, water, and protein contents of certain tissues vary markedly as a function of age. For example, the adipose tissues of neonates contain about 55% water and 35% lipids, whereas the corresponding figures for the adult are about 25% and 70%, respectively (Friis-Hansen, 1971). The proportion of water in skin falls as a function of age, due to an increase in collagen. The water contents of liver, brain, and kidneys decrease from birth to adulthood by 5-15%. The decrease in water contents of liver and kidneys is primarily due to an increase in protein, whereas this change in the brain is due to an increase in myelin. The overall composition of muscle in terms of lipid and water does not seem to vary with age (Dickerson Widdowson, 1960). 

According to the neuropathological investigations, one of the consequences of LA is axonal loss, which may lead to an increase in the water content of the brain WM tissue, thereby increasing ADC values and decreasing FA of the regions of LA. One may, there-... 

Symon L, Branston NM, Chikovani O (1979). Ischemic brain edema following middle cerebral artery occlusion in baboons relationship between regional cerebral water content and blood flow at 1 to 2 hours. Stroke 10 184-191... 

Cerebral edema occurs in response to a wide variety of insults, including ischemia, hypoxia, infection, and noninfectious inflammation. Shifts in brain water, which is the basis of the cellular swelling, are due to osmotic forces, and result in increases in intra- and extracellular spaces. A reasonable amount of tissue swelling can be tolerated in most parts of the body, however, the restrictions imposed by the rigid tentorium and bony skull cause life-threatening herniation with relatively small increases in the brain compartments. Two early anatomists, Monroe (1733-1817) and Kellie (1758-1829), recognized that increased intracranial pressure due to swelling in the cerebrospinal fluid (CSF), blood, or brain tissue compartments could increase intracranial pressure the concept of limited expansion capacity of the intracranial contents is called the Monroe-Kellie doctrine. 

Brain tissue water content is inversely correlated with X-ray attenuation and can thus be measured with CT (Rieth et al., 1980 Unger et al., 1988 Dzialowski et al.,... 

Hypoattenuated areas on CT represent an increase in the net water content of the involved brain parenchyma. Lowering of CT attenuation allows for quantification and localization of edema, which is the result of net change in water content of the area of interest. This increase in water content could be readily related to the vasogenic edema. Based on this physics, different CT techniques have been developed to monitor edema (1) noncontrast-enhanced CT (NECT), (2) perfusion CT (PCT), and (3) CT angiography (CTA). 

Dzialowski I, Klotz E, Goericke S, Doerfler A, Forsting M, von Kummer R (2007) Ischemic brain tissue water content CT monitoring during middle cerebral artery occlusion and reperfusion in rats. Radiology 243 720-726... 

Unger E, Littlefield J, Gado M (1988) Water content and water stracture in CT and MR signal changes possible influence in detection of early stroke. AJNR Am J Neuroradiol 9 687-691 Vakili A, Kataoka H, Plesnila N (2005) Role of arginine vasopressin V1 and V2 receptors for brain damage after transient focal cerebral ischemia. J Cereb Blood Flow Metab 25 1012-1019... 

---