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Query: UMLS:C0016382 (flushing)
 6,387 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In recent studies of bilirubin encephalopathy, in situ flushing of the cerebral vessels has been used to clear blood from the brain. The effectiveness of such procedures has not been adequately documented. Herein young, male Sprague-Dawley rats were given about 750 KBq of 51Cr-labelled rat erythrocytes 3 min prior to sacrifice. There were four experimental groups: control, displacer (sulfisoxazole), hyperosmolality, and hypercarbia. Half of the rats in each group had the brain vasculature flushed in situ, while the remaining rat brains were not flushed. The brains were dissected into seven regions, and the radioactivity in the tissues was compared to that of blood drawn from the rats immediately before death. Significant amounts of blood (22-42%) remained after in situ flushing. Retention was significantly higher in the hyperosmolar animals, and significantly lower in the hypercarbic animals as compared to controls. Interregional differences in blood volumes per gram wet weight were significant without, but not with flushing. Similar observations were made using 125I-IgM as a marker for the plasma compartment. In studies of brain uptake of substances with high plasma concentrations, substance remaining within the cerebral vessels may contribute significantly to the apparent brain uptake values.
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PMID:Cerebral blood volumes in young rats with and without in situ saline flushing of cerebral vasculature. Implications for in vivo studies of brain substance uptake. 275 81

In kernicterus bilirubin appears at higher concentrations in the basal ganglia, the cerebellum, and the medulla. The mechanism for this distribution is unknown, but might involve differences in bilirubin entry among brain regions. We infused [3H]bilirubin (30 mg/kg over 5 min) intravenously into young Sprague-Dawley rats (n = 21, weight 144 +/- 10 g, mean +/- SD). Blood was sampled from the tail, and groups of rats were killed at 15, 30, 45, 60, and 75 min by intravenous pentobarbital. After in situ flushing of the brain vasculature, the brain was dissected into seven regions, each of which was weighed, dissolved in Soluene-350, and subsequently scintillation counted. Blood samples were analyzed for bilirubin (including specific activity), albumin, and blood gases. Brain bilirubin concentrations in each of the regions were calculated by comparing the radioactivity in that region with the specific activity of bilirubin. Using a curve-fitting program (EXPOFIT), the concentrations of bilirubin in each brain region at 5 min (i.e. the end of bilirubin infusion) could be estimated, and were as follows (nmol/g +/- SD): cortex 6.4 +/- 4.4; hippocampus 6.2 +/- 3.3; striatum 6.3 +/- 4.5; midbrain 7.3 +/- 4.4; hypothalamus 6.3 +/- 4.6; cerebellum 6.7 +/- 4.1, and medulla 7.0 +/- 4.0. There were no significant differences in the bilirubin concentrations between brain regions (F6,140 0.205). The mechanism for preferential localization of bilirubin to the basal ganglia probably does not involve the acute entry of bilirubin into brain.
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PMID:Acute entry of bilirubin into rat brain regions. 764 Mar 20