Determination of Ion Activity Coefficients and Fixed Charge Density in Cartilage with23Na Magnetic Resonance Microscopy

1996 ◽  
Vol 41 (5) ◽  
pp. 970-976 ◽  
Author(s):  
Hongli Dai ◽  
Kimberlee Potter ◽  
Eric W. McFarland
Keyword(s):  
Magnetic Resonance ◽  
Charge Density ◽  
Activity Coefficients ◽  
Fixed Charge ◽  
Magnetic Resonance Microscopy ◽  
Fixed Charge Density ◽  
Ion Activity

scholarly journals Hyaluronidase reduced edema after experimental traumatic brain injury

2019 ◽  
Vol 40 (10) ◽  
pp. 2026-2037 ◽  
Author(s):  
Patricia M Washington ◽  
Changhee Lee ◽  
Mary Kate R Dwyer ◽  
Elisa E Konofagou ◽  
Steven G Kernie ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Magnetic Resonance ◽  
Charge Density ◽  
Fixed Charge ◽  
Resonance Imaging ◽  
Fixed Charge Density

Cerebral edema and the subsequent increased intracranial pressure are associated with mortality and poor outcome following traumatic brain injury. Previous in vitro studies have shown that the Gibbs-Donnan effect, which describes the tendency of a porous, negatively charged matrix to attract positive ions and water, applies to brain tissue and that enzymatic reduction of the fixed charge density can prevent tissue swelling. We tested whether hyaluronidase, an enzyme that degrades the large, negatively charged glycosaminoglycan hyaluronan, could reduce brain edema after traumatic brain injury. In vivo, intracerebroventricular injection of hyaluronidase after controlled cortical impact in mice reduced edema in the ipsilateral hippocampus at 24 h by both the wet-weight/dry-weight method (78.15 ± 0.65% vs. 80.4 ± 0.46%; p < 0.01) and T2-weighted magnetic resonance imaging (13.88 ± 3.09% vs. 29.23 ± 6.14%; p < 0.01). Hyaluronidase did not adversely affect blood–brain-barrier-integrity measured by dynamic contrast-enhanced magnetic resonance imaging, nor did hyaluronidase negatively affect functional recovery after controlled cortical impact measured with the rotarod or Morris water maze tasks. Reduction of fixed charge density by hyaluronidase was confirmed in cortical explants in vitro (5.46 ± 1.15 µg/mg vs. 7.76 ± 1.87 µg/mg; p < 0.05). These data demonstrate that targeting the fixed charge density with hyaluronidase reduced edema in an in vivo mouse model of traumatic brain injury.

Determination of effective fixed-charge density in membranes

1985 ◽  
Vol 22 (1) ◽  
pp. 111-116 ◽  
Author(s):  
A.K. Chakravarti ◽  
B. Christensen ◽  
P. Langer
Keyword(s):  
Charge Density ◽  
Fixed Charge ◽  
Fixed Charge Density
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