Linked Life Data

2754736

Source:http://linkedlifedata.com/resource/pubmed/id/2754736

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1989-9-6
pubmed:abstractText
Spinal cord Na, K, Ca, and H2O changes were measured 6 h after graded contusion injuries in 40 Sprague-Dawley rats. A 10 g weight was dropped 1.25 cm (n = 6), 2.5 cm (n = 7), 5.0 cm (n = 6), or 7.5 cm (n = 7) onto the thoracic spinal cord of 26 rats. An additional 10 rats served as laminectomy controls and 4 rats were unoperated controls. At 6 h after surgery or injury, the spinal cords were rapidly cut into 4 mm segments, weighed to obtain tissue wet weights (W), dried for 14-16 h at 97 degrees C in a vacuum oven (30 mmHg), and reweighed for tissue dry weights (D). Water concentrations ([H2O]d) were estimated from (W-D)/D in units of ml/g D. Ionic concentrations ([Na]d, [K]d, and [Ca]d) of the tissue samples were measured by atomic absorption spectroscopy with units of mumol/g D. Ionic shifts (delta [Na]d, delta [K]d, delta [Ca]d) were calculated by subtracting laminectomy control values from those measured in injured cords. Laminectomy alone significantly increased [Na]d and [H2O]d compared to unoperated controls. Mean +/- standard deviations of [H2O]d, [Na]d, [K]d, and [Ca]d were, respectively, 1.95 +/- 0.07, 182.6 +/- 5.9, 277.2 +/- 11.8, and 12.1 +/- 1.4 in unoperated controls; 2.12 +/- 0.08, 238.6 +/- 9.2, 277.8 +/- 9.2, and 11.7 +/- 1.1 in laminectomy controls. At the impact site, [K]d fell by 14-37% and [H2O]d rose by 14-24%, [Na]d by 13-64%, and [Ca]d by 65-137% of laminectomy control values. delta [Na]d, delta [K]d, and delta [Ca]d correlated linearly with impact velocities; [Ca]d increased by 1.0% per cm/sec (r = 0.995, p less than 0.005), [Na]d increased 0.67% per cm/sec (r = 0.950, p less than 0.01), and [K]d decreased 0.34% per cm/sec (r = 0.964, p less than 0.01). Neither delta [H2O] nor delta [Na]d + delta [K]d consistently predicted impact velocity. [Na]d + [K]d correlated with [H2O]d with a slope of 177.4 mumol/ml (r = 0.697, p less than 0.005). Since Na and K constitute greater than 95% of tissue inorganic ions, the slope approximates net ionic shift per ml of water entry or the ionic osmolarity of edema fluid. These results indicate that increasing contusions produce graded ionic shifts and that edema does not predict contusion severity. These data support our hypothesis that net ionic shifts cause edema in injured spinal cords.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0897-7151
pubmed:author
pubmed:issnType
Print
pubmed:volume
6
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13-24
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Spinal cord sodium, potassium, calcium, and water concentration changes in rats after graded contusion injury.
pubmed:affiliation
Department of Neurosurgery, New York University Medical Center, New York.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.