scholarly journals Fixed negative charge and the Donnan effect: a description of the driving forces associated with brain tissue swelling and oedema

2010 ◽  
Vol 368 (1912) ◽  
pp. 585-603 ◽  
Author(s):  
Benjamin S. Elkin ◽  
Mohammed A. Shaik ◽  
Barclay Morrison
Keyword(s):  
Brain Tissue ◽  
Negative Charge ◽  
Driving Forces ◽  
Membrane Integrity ◽  
Mixture Theory ◽  
Brain Swelling ◽  
Bathing Medium ◽  
Fixed Charges ◽  
Donnan Effect ◽  
Triton X

Cerebral oedema or brain tissue swelling is a significant complication following traumatic brain injury or stroke that can increase the intracranial pressure (ICP) and impair blood flow. Here, we have identified a potential driver of oedema: the negatively charged molecules fixed within cells. This fixed charge density (FCD), once exposed, could increase ICP through the Donnan effect. We have shown that metabolic processes and membrane integrity are required for concealing this FCD as slices of rat cortex swelled immediately (within 30 min) following dissection if treated with 2 deoxyglucose + cyanide (2DG+CN) or Triton X-100. Slices given ample oxygen and glucose, however, did not swell significantly. We also found that dead brain tissue swells and shrinks in response to changes in ionic strength of the bathing medium, which suggests that the Donnan effect is capable of pressurizing and swelling brain tissue. As predicted, a non-ionic osmolyte, 1,2 propanediol, elicited no volume change at 2000×10 −3  osmoles l −1 (Osm). Swelling data were well described by triphasic mixture theory with the calculated reference state FCD similar to that measured with a 1,9 dimethylmethylene blue assay. Taken together, these data suggest that intracellular fixed charges may contribute to the driving forces responsible for brain swelling.

Mechanism of bicarbonate exit across basolateral membrane of rabbit proximal straight tubule

1987 ◽  
Vol 252 (1) ◽  
pp. F11-F18 ◽  
Author(s):  
S. Sasaki ◽  
T. Shiigai ◽  
N. Yoshiyama ◽  
J. Takeuchi
Keyword(s):  
Negative Charge ◽  
Driving Forces ◽  
Basolateral Membrane ◽  
Disulfonic Acid ◽  
Exit Mechanism ◽  
Total Replacement ◽  
Straight Tubules ◽  
Proximal Straight Tubule ◽  
Basolateral Membrane Potential

To clarify the mechanism(s) of HCO3- (or related base) transport across the basolateral membrane, rabbit proximal straight tubules were perfused in vitro, and intracellular pH (pHi) and Na+ activity (aiNa) were measured by double-barreled ion-selective microelectrodes. Lowering bath HCO3- from 25 to 5 mM at constant PCO2 depolarized basolateral membrane potential (Vbl), and reduced pHi. Most of these changes were inhibited by adding 1 mM 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) to the bath. Total replacement of bath Na+ with choline also depolarized Vbl and reduced pHi, and these changes were also inhibited by SITS. Reduction in aiNa was observed when bath HCO3- was lowered. Taken together, these findings suggest that HCO3- exists the basolateral membrane with Na+ and negative charge. Calculation of the electrochemical driving forces suggests that the stoichiometry of HCO3-/Na+ must be larger than two for maintaining HCO3- efflux. Total replacement of bath Cl- with isethionate depolarized Vbl gradually and increased pHi slightly, implying the existence of a Cl(-)-related HCO3- exit mechanism. The rate of decrease in pHi induced by lowering bath HCO3- was slightly reduced (20%) by the absence of bath Cl-. Therefore, the importance of Cl(-)-related HCO3- transport is small relative to total basolateral HCO3- exit. Accordingly, these data suggest that most of HCO3- exits the basolateral membrane through the rheogenic Na+/HCO3- cotransport mechanism with a stoichiometry of HCO3-/Na+ of more than two.

Temperature dependency of force loss and Ca2+homeostasis in mouse EDL muscle after eccentric contractions

2002 ◽  
Vol 282 (4) ◽  
pp. R1122-R1132 ◽  
Author(s):  
Gordon L. Warren ◽  
Christopher P. Ingalls ◽  
R. B. Armstrong
Keyword(s):  
Isometric Force ◽  
Membrane Integrity ◽  
Significant Loss ◽  
Eccentric Contractions ◽  
Effect Of Temperature ◽  
Temperature Dependency ◽  
Bathing Medium ◽  
Cell Membrane Integrity ◽  
Temperature Loss ◽  
Ldh Release

The goals of this study were first to determine the effect of temperature on the force loss that results from eccentric contractions in mouse extensor digitorum longus (EDL) muscles and then to evaluate a potential role for altered Ca2+ homeostasis explaining the greater isometric force loss observed at the higher temperatures. Isolated muscles performed five eccentric or five isometric contractions at either 15, 20, 25, 30, 33.5, or 37°C. Isometric force loss, caffeine-induced force, lactate dehydrogenase (LDH) release, muscle accumulation of 45Ca2+ from the bathing medium, sarcoplasmic reticulum (SR) Ca2+ uptake, and resting muscle fiber free cytosolic Ca2+ concentration ([Ca2+]i) were measured. The isometric force loss after eccentric contractions increased progressively as temperature rose; at 15°C, there was no significant loss of force, but at 37°C, there was a 30–39% loss of force. After eccentric contractions, caffeine-induced force was not affected by temperature nor was it different from that of control muscles at any temperature. Loss of cell membrane integrity and subsequent influx of extracellular Ca2+ as indicated by LDH release and muscle45Ca2+ accumulation, respectively, were minimal over the 15–25°C range, but both increased as an exponential function of temperature between 30 and 37°C. SR Ca2+uptake showed no impairment as temperature increased, and the eccentric contraction-induced rise in resting fiber [Ca2+]i was unaffected by temperature over the 15–25°C range. In conclusion, the isometric force loss after eccentric contractions is temperature dependent, but the temperature dependency does not appear to be readily explainable by alterations in Ca2+ homeostasis.

Contribution of edema and cerebral blood volume to traumatic brain swelling in head-injured patients

2000 ◽  
Vol 93 (2) ◽  
pp. 183-193 ◽  
Author(s):  
Anthony Marmarou ◽  
Panos P. Fatouros ◽  
Pal Barzó ◽  
Gennarina Portella ◽  
Masaaki Yoshihara ◽  
...  
Keyword(s):  
Brain Edema ◽  
Brain Tissue ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Brain Swelling ◽  
Tissue Water ◽  
Content Type ◽  
Head Injured ◽  
Injured Patients ◽  
Fine Print

Object. The pathogenesis of traumatic brain swelling remains unclear. The generally held view is that brain swelling is caused primarily by vascular engorgement and that edema plays a relatively minor role in the swelling process. The goal of this study was to examine the roles of cerebral blood volume (CBV) and edema in traumatic brain swelling.Methods. Both brain-tissue water and CBV were measured in 76 head-injured patients, and the relative contribution of edema and blood to total brain swelling was determined. Comparable measures of brain-tissue water were obtained in 30 healthy volunteers and CBV in seven volunteers. Brain edema was measured using magnetic resonance imaging, implementing a new technique for accurate measurement of total tissue water. Measurements of CBV in a subgroup of 31 head-injured patients were based on consecutive measures of cerebral blood flow (CBF) obtained using stable xenon and calculation of mean transit time by dynamic computerized tomography scanning after a rapid bolus injection of iodinated contrast material. The mean (± standard deviation) percentage of swelling due to water was 9.37 ± 8.7%, whereas that due to blood was −0.8 ± 1.32%.Conclusions. The results of this study showed that brain edema is the major fluid component contributing to traumatic brain swelling. Moreover, CBV is reduced in proportion to CBF reduction following severe brain injury.

scholarly journals Effects of Detergents on the Redistribution of Gangliosides and GPI-anchored Proteins in Brain Tissue Sections

2007 ◽  
Vol 55 (8) ◽  
pp. 805-812 ◽  
Author(s):  
Marija Heffer-Lauc ◽  
Barbara Viljetić ◽  
Katarina Vajn ◽  
Ronald L. Schnaar ◽  
Gordan Lauc
Keyword(s):  
Cell Membrane ◽  
Brain Tissue ◽  
Room Temperature ◽  
Deoxycholic Acid ◽  
Tween 20 ◽  
Outer Side ◽  
Tissue Sections ◽  
Brij 96V ◽  
Triton X ◽  
The Ideal

Gangliosides and glycosylphosphatidylinositol (GPI)-anchored proteins contain lipid tails that tether them to the outer side of the cell membrane. This mode of association with the cell membrane enables them to take part in the organization of lipid rafts, but it also permits gangliosides and GPI-anchored proteins to be actively released from one cell and inserted into the membrane of another cell. Recently, we reported that under conditions of lipid raft isolation, Triton X-100 causes significant redistribution of both gangliosides and GPI-anchored proteins. Aiming to find a less disruptive detergent, we evaluated the effects of CHAPS, Saponin, deoxycholic acid, Trappsol, Tween 20, Triton X-100, Brij 96V, Brij 98, and SDS on brain tissue sections. At room temperature, all detergents (1% concentration) extracted significant amounts of both gangliosides and Thy-1. At 4C, the extraction was weaker, but Triton X-100, CHAPS, and deoxycholic acid caused significant redistribution of GD1a and Thy-1 from gray matter into the white matter. Both redistribution and extraction were significantly augmented when sections were incubated with detergents in the presence of primary antibodies. Of the nine tested detergents, none is the ideal choice. However, Brij 96V appears to be able to sufficiently reveal myelin epitopes while causing the least amount of artifacts. This manuscript contains online supplemental material at http://www.jhc.org . Please visit this article online to view these materials. (J Histochem Cytochem 55: 805–812, 2007)

PROTEOGLYCANS AND SULFATED PROTEINS OF PLATELETS: CHARACTERIZATION AND RESPONSE TO THROMBIN AND ADP

1987 ◽  
Author(s):  
B P Schick ◽  
C J Walsh ◽  
T Jenkins-West
Keyword(s):  
Molecular Weight ◽  
Guinea Pig ◽  
Platelet Activation ◽  
Negative Charge ◽  
Total Cell ◽  
Low Molecular Weight ◽  
Sds Page ◽  
Form Part ◽  
Triton X

The proteoglycans (PG) and sulfated proteins of guinea pig platelets were labeled in vivo by intraperitoneal injection of (35S)sulfate. At 3 days after injection, platelets contained 3 distinct populations of chondroitin-6-sulfate proteoglycans which together constitute about 65% of the cellular (35S) label. Most PG elute from a DEAE-Sephacel column with 4M Gdn HC1 (PG-1, 87%), and elute at Kav 0.12 on Sepharose CL-6B. The PG-1 can be resolved by SDS-PAGE into two fractions. The remainder (PG-2, 13%) elutes from the DEAE-Sephacel column with 4M Gdn HCl/2% Triton X-100 or 2% CHAPS, and has a Kav of 0.07 on Sepharose CL-6B. About 20-25% of the cell (35S) label elutes from DEAE-Sephacel in the wash-through or with 0.23M NaCl, and can be resolved by SDS-PAGE into at least 8 distinct bands which we have tentatively characterized as sulfated glycoproteins. The remainder of the (35S) is in low molecular weight (LMW) material which does not adhere to DEAE-Sephacel and has not been further characterized.Platelets were treated with either thrombin or ADP, and the cells were then separated from the supernatant by centrifugation. The radiolabeled molecules in the supernatant and the cells were analyzed by DEAE-Sephacel and Sepharose CL-6B column chromatography. About 65% of the total cell (35S) was released from the cells by thrombin. Most of this radiolabel adhered to the DEAE-Sephacel column, and was found to be PG-1. The remainder of the released (35S) was about half the LMW material. In contrast, only 10-15% of the (35S)labeled material retained by the cells adhered to DEAE-Sephacel and was found to be PG-2. The remainder of the (35S)-labeled material retained by the platelets was the sulfated proteins and the LMW material. ADP caused release of about 15% of the (35S), and this was found to be in part PG-1 and in part the LMW material, but not PG-2. None of the (35S)-labeled molecules appeared to be degraded during platelet activation. We suggest that the PG-1 represent the a-granule and PG-2 the membrane proteoglycans. The sulfated proteins have not been described previously. Their role is not known, but we hypothesize that they may form part of the negative charge of the glycocalix and thus be part of the reactive surface of the platelet.

scholarly journals Is the Donnan effect sufficient to explain swelling in brain tissue slices?

2014 ◽  
Vol 11 (96) ◽  
pp. 20140123 ◽  
Author(s):  
Georgina E. Lang ◽  
Peter S. Stewart ◽  
Dominic Vella ◽  
Sarah L. Waters ◽  
Alain Goriely
Keyword(s):  
Brain Tissue ◽  
Traumatic Injury ◽  
Ionic Concentration ◽  
Ion Concentration ◽  
Bathing Solution ◽  
Concentration Gradients ◽  
Tissue Slices ◽  
Donnan Effect ◽  
Water Accumulation ◽  
Underlying Processes

Brain tissue swelling is a dangerous consequence of traumatic injury and is associated with raised intracranial pressure and restricted blood flow. We consider the mechanical effects that drive swelling of brain tissue slices in an ionic solution bath, motivated by recent experimental results that showed that the volume change of tissue slices depends on the ionic concentration of the bathing solution. This result was attributed to the presence of large charged molecules that induce ion concentration gradients to ensure electroneutrality (the Donnan effect), leading to osmotic pressures and water accumulation. We use a mathematical triphasic model for soft tissue to characterize the underlying processes that could lead to the volume changes observed experimentally. We suggest that swelling is caused by an osmotic pressure increase driven by both non-permeating solutes released by necrotic cells, in addition to the Donnan effect. Both effects are necessary to explain the dependence of the tissue slice volume on the ionic bath concentration that was observed experimentally.

Tegumental disruption with Triton X-100 and its effects on longitudinal muscle function in male Schistosoma mansoni

Parasitology ◽  
1983 ◽  
Vol 87 (1) ◽  
pp. 61-73 ◽  
Author(s):  
J. W. Depenbusch ◽  
D. P. Thompson ◽  
R. A. Pax ◽  
J. L. Bennett
Keyword(s):  
Low Temperature ◽  
Schistosoma Mansoni ◽  
Muscle Membrane ◽  
Bathing Medium ◽  
High K ◽  
Voltage Dependent ◽  
Plasma Emission Spectroscopy ◽  
Almost All ◽  
Triton X ◽  
Longitudinal Muscles

SUMMARYLongitudinal muscles in adult male Schistosoma mansoni appear to remain in almost all respects functional after tegumental disruption by Triton X-100. Responses to high K+, ouabain, low temperature, praziquantel and neurotransmitters are still present. Muscle membrane potentials remain near those of control animals and lanthanum nitrate is still excluded from the muscle after the Triton treatment. Although muscle contractility remains after tegumental disruption, sodium and calcium levels, as measured by plasma emission spectroscopy, increase by 20–30% while potassium and magnesium levels decrease by 15%. 45Ca2+ accumulation is double that of control animals. Upon exposure to a bathing medium lacking Ca2+, Triton-treated animals lose responsiveness to high K+, ouabain, low temperature and praziquantel more rapidly than do control animals. D-600, which effectively blocks the high K+ response in control animals, has no measurable effect on the high K+ response in Triton-treated animals, suggesting that voltage-dependent Ca2+ channels are present in the tegument.

Predominance of cellular edema in traumatic brain swelling in patients with severe head injuries

2006 ◽  
Vol 104 (5) ◽  
pp. 720-730 ◽  
Author(s):  
Anthony Marmarou ◽  
Stefano Signoretti ◽  
Panos P. Fatouros ◽  
Gina Portella ◽  
Gunes A. Aygok ◽  
...  
Keyword(s):  
Brain Injury ◽  
Mr Imaging ◽  
Healthy Volunteers ◽  
Water Content ◽  
Brain Tissue ◽  
Brain Swelling ◽  
Adc Value ◽  
Diffuse Brain Injury ◽  
Adc Values ◽  
The Mean

Object The edema associated with brain swelling after traumatic brain injury (TBI) has been thought to be vasogenic in origin, but the results of previous laboratory studies by the authors have shown that a cellular form of edema is mainly responsible for brain swelling after TBI. In this study the authors used magnetic resonance (MR) imaging techniques to identify the type of edema that occurs in patients with TBI. Methods Diffusion-weighted MR imaging was used to evaluate the apparent diffusion coefficient (ADC) in 44 patients with TBI (Glasgow Coma Scale Score < 8) and in eight healthy volunteers. Higher ADC values have been associated with vasogenic edema, and lower ADC values with a predominantly cellular form of edema. Regional measurements of ADC in patients with focal and diffuse injury were computed. The water content of brain tissue was also assessed in absolute terms by using MR imaging to measure the percentage of water per gram of tissue. Cerebral blood flow (CBF) was measured using stable Xe–computerized tomography (CT) studies to rule out ischemia as a cause of cellular edema. The mean ADC value in the healthy volunteers was 0.82 ± 0.05 × 10−3 mm2/second. The ADC values in the patients with diffuse brain injury without swelling were close to the mean for the healthy volunteers. In contrast, the patients with brain swelling had increased brain water content and low ADC values (mean 0.74 ± 0.05 × 10−3 mm2/second). The ADC values correlated with CT classifications. In all patients with low ADC values, the CBF values were outside the range for ischemia. Conclusions The brain swelling observed in patients with TBI appears to be predominantly cellular, as signaled by low ADC values in brain tissue with high levels of water content.

scholarly journals Clinical - pathogenetical features of Cryptococcus meningoencephalitis in patients with HIV infection

2014 ◽  
Vol 19 (4) ◽  
pp. 25-29
Author(s):  
O. E Volkova ◽  
Yu. Ya Vengerov ◽  
A. P Safonova ◽  
T. S Svistunova ◽  
O. A Tishkevich
Keyword(s):  
Cerebrospinal Fluid ◽  
Hiv Infection ◽  
Brain Tissue ◽  
Clinical Picture ◽  
Brain Swelling ◽  
Cryptococcal Meningoencephalitis ◽  
Direct Microscopy ◽  
Destructive Processes ◽  
Csf Examination

The purpose of research - the study of clinical and pathogenetical features of cryptococcal meningoencephalitis (CME) in patients with HIV infection for the improvement of the efficiency of diagnosis and treatment. Materials and Methods. There are presented the results of the study of 67 cases of cryptococcal meningoencephalitis in patients with HIV infection. There was performed an assessment of the clinical picture and the cerebrospinal fluid (CSF), which was consisted of direct microscopy, cultural method and PCR. Also pathomorphological data of deceased patients have been analyzed. Results of the study. The clinical picture of CME was mildly pronounced and not constant. Dominant complaint is constant headache diffuse in character. Meningeal symptoms are uncertain or absent. CSF changes are not specific, most informative methods are PCR and mycological study of CSF. The fatality was causedfirst ofall by the development of edema-brain swelling and the dislocation of stem structures. Conclusion. The clinical picture of cryptococcal meningoencephalitis is caused first of all by destructive processes in brain tissue and progression of the development of edema-brain swelling. The clinical picture is poorly pronounced and is not constant, therefore to all patients with HIV infection in the presence of long-term headache the CSF examination is indicated even in the absence of meningeal symptoms.

scholarly journals A study of the mechanism by which some amphiphilic drugs affect human erythrocyte acetylcholinesterase activity

1989 ◽  
Vol 261 (2) ◽  
pp. 569-573 ◽  
Author(s):  
A Spinedi ◽  
L Pacini ◽  
P Luly
Keyword(s):  
Human Erythrocyte ◽  
Physical State ◽  
Membrane Integrity ◽  
Acetylcholinesterase Activity ◽  
Inhibition Kinetics ◽  
Inhibitory Potency ◽  
Mixed Inhibition ◽  
Amphiphilic Drugs ◽  
Lipid Environment ◽  
Triton X

The effects of the local anaesthetics procaine, tetracaine and lidocaine and of the antidepressant imipramine on human erythrocyte acetylcholinesterase were investigated. All four amphiphilic drugs inhibited enzymic activity, the IC50 (the concentration causing 50% inhibition) being about 0.40 mM for procaine, 0.05 mM for tetracaine, 0.70 mM for imipramine and 7.0 mM for lidocaine. Procaine and tetracaine inhibited acetylcholinesterase activity competitively at concentrations at which they did not perturb the physical state of the membrane lipid environment, as assessed by steady-state fluorescence polarization, whereas lidocaine and imipramine displayed mixed inhibition kinetics at concentrations at which they induced an enhancement of membrane fluidity. The question was addressed as to whether membrane integrity is a prerequisite for imipramine and lidocaine action. Membrane solubilization by 1% Triton X-100 and a decrease, by dilution, in the detergent concentration to 0.05% [which is above the Triton X-100 critical micelle concentration (c.m.c.)] did not substantially affect the inhibitory potency of the two amphiphilic drugs at their IC50; in the presence of increasing detergent concentrations the inhibitory potency of imipramine was gradually decreased, but not abolished, whereas the inhibitory effect of lidocaine was only slightly diminished, even at 1% Triton X-100. It is suggested that neither competitive nor mixed inhibition kinetics arise from conformational changes of the protein driven by a modification of the physical state of the lipid environment, but from a direct interaction of the amphiphilic drugs with acetylcholinesterase. In particular, the partial loss of the inhibitory potency of imipramine and lidocaine that is observed upon increasing Triton X-100 concentration well above its c.m.c. could be explained in terms of amphiphile partition in detergent micelles and, in turn, of a decreased effective concentration of the two inhibitors in the aqueous phase.

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