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PubMed1987

Effects of prostaglandin E2 on brain edema and liver histopathology in a galactosamine-induced fulminant hepatic failure rat model.

The effects of prostaglandin E2 (PGE2) on the histopathology of liver and brain edema was studied in the galactosamine-induced fulminant hepatic failure (Ga1N-FHF) rat model. The effect of PGE2 on the development of brain edema was studied in grade II coma FHF rats by electron microscopy and by measurement of brain water content and brain swelling. Electron microscopy revealed extensive pericapillary astroglial cell swelling and morphological changes of its subcellular organelles in control FHF rats. PGE2 injected FHF rats showed reduced astroglial swelling and brain edema. PGE2 administration significantly (p less than 0.02) inhibited the progression of both brain edema and brain tissue swelling when compared with saline injected control FHF animals. However, the liver damage shown in EM assessment appeared to progress after PGE2 injection. This would appear that PGE2 is acting directly on the Blood Bain Barrier (BBB) to preserve it despite progressive hepatic failure.

Animals↗
PubMed2004

Alpha-syntrophin deletion removes the perivascular but not endothelial pool of aquaporin-4 at the blood-brain barrier and delays the development of brain edema in an experimental model of acute hyponatremia.

The formation of brain edema, commonly occurring as a potentially lethal complication of acute hyponatremia, is delayed following knockout of the water channel aquaporin-4 (AQP4). Here we show by high-resolution immunogold analysis of the blood-brain-barrier that AQP4 is expressed in brain endothelial cells as well as in the perivascular membranes of astrocyte endfeet. A selective removal of perivascular AQP4 by alpha-syntrophin deletion delays the buildup of brain edema (assessed by Diffusion-weighted MRI) following water intoxication, despite the presence of a normal complement of endothelial AQP4. This indicates that the perivascular membrane domain, which is peripheral to the endothelial blood-brain barrier, may control the rate of osmotically driven water entry. This study is also the first to demonstrate that the time course of edema development differs among brain regions, probably reflecting differences in aquaporin-4 distribution. The resolution of the molecular basis and subcellular site of osmotically driven brain water uptake should help design new therapies for acute brain edema.

Animals↗
PubMed1988

Experimental drug therapy of peritumoral brain edema.

Four drugs with potential anti-peritumoral brain edema activity were studied using the VX2 rabbit brain tumor model. Meclofenamate and indomethacin were tested in an attempt to confirm recent reports of anti-edema activity in non steroidal anti-inflammatory drugs (NSAID's). The 'angiostatic' steroids 17 hydroxyprogesterone and epicortisol were tested because of their lack of glucocorticoid and mineralocorticoid effects and their structural similarity to glucocorticoids. The protein and water component of brain edema were indirectly quantitated. None of the test drugs demonstrated significant anti-edema activity. This work does not confirm reports that NSAID's have anti-edema activity and suggests that there may be no correlation between 'angiostatic' and anti-edema activity in certain steroid compounds.

17-alpha-Hydroxyprogesterone↗
PubMedDate not supplied

Incidence of space-occupying brain edema following systemic thrombolysis of acute supratentorial ischemia.

Whether 'malignant' brain edema following ischemic stroke is due to or aggravated by reperfusion and therefore more frequent after thrombolytic therapy of stroke is still under debate. From 3/96 to 1/97, we treated 51 patients with acute supratentorial stroke within 3 h after symptom onset with rt-PA following a protocol similar to the NINDS study. The results of thrombolytic therapy were evaluated by repeated clinical examination and computed tomography (CT) during the first week after ictus. The incidence of space-occupying brain edema following intravenous thrombolytic therapy of acute ischemic stroke was lower than the edema frequency after conventional treatment, but mortality from 'malignant' edema was higher in the patients with thrombolysis. Thus, space-occupying edema after acute ischemic stroke may be aggravated by thrombolytic treatment. Forced reperfusion of already irreversibly damaged tissue increases edema formation and enlarges developing infarcts with a deleterious increase of intracranial pressure.

Adult↗
PubMed1986

Focal brain edema associated with acute arterial hypertension.

Acute arterial hypertension was studied in normal cats to determine its role in the formation of brain edema. Arterial hypertension was induced for 30 minutes by inflation of a balloon catheter situated in the descending aorta. Cerebral edema was evaluated by gross and microscopic observations, tissue water content by wet/dry weights, and blood-brain barrier (BBB) permeability by extravasation of horseradish peroxidase (HRP) and Evans blue dye. For 1 hour after the hypertensive insult, tissue pressure and regional cerebral blood flow (rCBF) were measured from the arterial boundary zone and from a non-boundary region, and intracranial pressure was recorded from the lateral ventricle as ventricular fluid pressure. Focal lesions with increased BBB permeability to Evans blue dye or HRP were usually located symmetrically in the cortex, corresponding to the occipitoparietal parts of the arterial boundary zones. The increase in water content was found only in areas of increased permeability. Tissue pressure increased simultaneously with the abrupt rise in blood pressure, and an increase in rCBF paralleled the elevation of blood pressure. Tissue pressure and rCBF returned to a steady state when blood pressure returned to normal. There were no differences in tissue pressure or rCBF between the arterial boundary zone and the non-boundary zone, even during arterial hypertension. In cerebral hemispheres examined 48 hours after the hypertensive challenge, brain edema had not continued to develop. The data indicate that acute arterial hypertension may produce focal brain edema with increased permeability of the BBB in the cortex of normal brain, particularly in the arterial boundary zones. The authors postulate that increased cerebral blood volume, high intraluminal pressure, and breakthrough of autoregulation play an important role in the formation of hypertensive brain edema.

Animals↗
PubMed2003

Focal brain edema and natriuretic peptides in patients with subarachnoid hemorrhage.

Central salt wasting syndrome may be caused by pathological increases in serum natriuretic peptides after subarachnoid hemorrhage (SAH). However, it is unclear as to why the serum concentration of atrial natriuretic peptide (ANP) or brain natriuretic peptide (BNP) increases in the subacute phase of SAH. The present study was designed to assess the correlation between focal brain edema and serum concentration of ANP or BNP in patients with SAH. Focal brain edema was found in 8 SAH-patients and peaked between days 4 and 7 of SAH. The mean serum ANP and BNP levels in patients with focal brain edema were significantly higher than those in patients without focal brain edema between days 4 and 14 of SAH. These results suggest that focal brain edema might correlate with increased levels of ANP and BNP in the subacute phase of SAH.

Atrial Natriuretic Factor↗
PubMed1992

[An experimental study of arginine vasopressin on acute ischemic brain edema in gerbils (1)].

The purpose of this experiments is to study the role of arginine vasopressin (AVP) in acute ischemic brain edema of mongolian gerbils. The results showed that the contents of AVP in ischemic cortex, hypothalamus and striatum increased remarkably in 15-120 minutes after ischemia, while the contents of AVP had no change in pons-medulla which was not affected from ischemia, and there was relationship between the contents of AVP in cortex and the ischemic cortical edema. Intracerebroventricular injection (ICV) of AVP exacerbated the ischemic cortical edema and it showed dose-response correlation. While ICV of AVP antiserum significantly decreased ischemic cortical edema. These suggested that AVP was involved in the pathophysiologic process of acute ischemic brain edema. The increasing of AVP contents in ischemic brain regions could exacerbate the formation of ischemic brain edema.

Animals↗
PubMed2002

Influence of norepinephrine and dopamine on cortical perfusion, EEG activity, extracellular glutamate, and brain edema in rats after controlled cortical impact injury.

Following traumatic brain injury, catecholamines given to ameliorate cerebral perfusion may induce brain damage via cerebral arteriolar constriction and increased neuronal excitation. In the present study the acute effects of norepinephrine and dopamine on pericontusional cortical perfusion (rCBF), electroencephalographic (EEG) activity, extracellular glutamate, and brain edema were investigated in rats following controlled cortical impact injury (CCI). rCBF, cerebral perfusion pressure (CPP), EEG activity, and glutamate were determined before, during, and after infusing norepinephrine or dopamine, increasing MABP to 120 mm Hg for 90 min at 4 h after CCI. Control rats received physiological saline. At 8 h after CCI, hemispheric swelling and water content were determined gravimetrically. Following CCI, rCBF was significantly decreased. In parallel to elevating MABP and CPP, rCBF was significantly increased by norepinephrine and dopamine, being mostly pronounced with norepinephrine (+44% vs. +29%). In controls, rCBF remained diminished (-45%). EEG activity was significantly increased by norepinephrine and dopamine, while pericontusional glutamate was only elevated by norepinephrine (28 +/- 6 vs. 8 +/- 4 microM). Brain edema was not increased compared to control rats. Despite significantly increasing MABP and CPP to the same extent, norepinephrine and dopamine seem to differentially influence pericontusional cortical perfusion and glutamatergic transmission. In addition to the pressure-passive increase in CPP local cerebral effects seem to account for the sustained norepinephrine-induced increase in pericontusional cortical perfusion. The significantly elevated pericontusional glutamate concentrations in conjunction with the increased EEG activity suggest a sustained metabolically driven increase in cortical perfusion during norepinephrine infusion.

Animals↗
PubMed1989

Inhibition by H-7 of the protein kinase C prevents formation of brain edema in Sprague-Dawley CFY rats.

The effect of the protein kinase C enzyme inhibitor H-7 was examined on the brain edema formation evoked by bilateral occlusion of the common carotid arteries in Sprague-Dawley rats of CFY strain. Brain edema was assessed by measurement of water and electrolyte contents of the brain. The results showed that pretreatment with H-7 reduced the extent of brain edema formation in a dose-dependent manner. The fact that H-7 treatment prevented the accumulation of water and certain electrolytes in the brain indicates that the protein kinase C may be activated not only in the neuronal structures but also in the microvessels during ischemia, which can lead directly or via certain calcium-mediated mechanisms to the opening of tight junctions resulting in the development of brain edema.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1995

Brain edema and intracranial hypertension in rats after total hepatectomy.

BACKGROUND/AIMS: Glutamine, generated from ammonia in astrocytes, may account for brain edema in acute liver failure. Recent studies showing decreased intracranial pressure after hepatectomy in humans suggest that factors released by the necrotic liver could play a pathogenic role in brain swelling. The aim of this study was to examine whether brain edema and intracranial hypertension develop in hepatectomized rats. METHODS: Rats underwent a portacaval anastomosis or a sham operation. At 24 hours, animals underwent a second sham operation or a total hepatectomy. Intracranial pressure was continuously monitored, and cortical water and glutamine contents were measured after the rats were killed. In a second experiment, hepatectomized and devascularized (portacaval anastomosis plus hepatic artery ligation) rats were killed every 2 hours and at the time of intracranial hypertension. RESULTS: Although brain edema developed in both groups with liver failure, devascularization resulted in a higher brain water content in spite of an equivalent increase in glutamine concentration. Intracranial pressure increased to a similar degree in both groups, but all parameters increased earlier in anhepatic rats. CONCLUSIONS: Hepatectomized rats develop brain edema and intracranial hypertension. The temporal sequence in this model supports the role of glutamine as an organic osmolyte. In addition, other factors (e.g., brain volume) may contribute to intracranial hypertension in hepatectomized rats.

Analysis of Variance↗
PubMed1991

[Mechanisms of development of brain edema in neurosurgical pathology].

As many as 120 neurosurgical patients were examined after the excision of hemispheric gliomas, basal and subtentorial tumors. Based on an the computer-aided analysis biochemical and clinical data, attempts have been made to unify the mechanisms responsible for brain edema development in patients with neurosurgical pathology. In the early postoperative period, brain edema occurs in 95% of neurosurgical patients. Edema development, spreading and intensity depend on the site and nature of the primary pathological focus as well as on traumatism of surgical interventions. It is proved that edema is an original, biologically expedient brain response to its injury. This response manifests in hyperhydration of all tissues, with the maximum intensity being concentrated in the focus of injury. Specific (neurogenic neurohumoral) and nonspecific (biochemical, autoimmune, mechanical, and so forth) factors of brain edema development may be distinguished. The differences in the neurogenic and neurohumoral mechanisms by which brain edema develops may be accounted for by the topography of the focus of injury. The closer the pathological focus is to the stem and diencephalic structures, the more remarkable the action of neurogenous and neurohumoral factors and the more distinct the tendency toward edema generalization are. At the diencephalic level of injury, damaged are the structures responsible for central regulation of metabolism and trophicity of nerve cells. The neurogenously precipitated diffuse impairment of permeability of the cells entails their hyperhydration, which marks cellular (cytotoxic) edema. The subtentorial process that affects the vasomotor centre of the stem triggers the neurogenic diffuse alterations in the vascular tone, manifesting in an increase of permeability for water and plasma proteins which is characteristic of vasogenic edema.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Water↗
PubMed2001

Comparative observation with MRI and pathology of brain edema at the early stage of severe burn.

OBJECTIVE: To investigate the correlation between MRI features and pathology in brain edema at the early stage of severe burn (5 0% TBSA III degree) in dogs. METHODS: Fifty-two dogs were randomized into control, simple b urn (SB), burn plus sodium lactate (BSL), and burn plus glucose solution groups (BGS). The manifestation of the brain of control group was compared with that of burn groups at 6, 12, 18 and 24 hours postburn with MRI and pathological examination (gross appearance, electron microscopy and light microscopy). RESULTS: The earliest findings of brain edema were seen at 12 h ours after burn in BGS group, in which brain swelling was the main feature of MR I. The decrease of SIR on T(1)WI was not observed until it was exceeded 10%. Sig nal of T(2)WI increased by 8.29% at 24 hours after burn. It was difficult to distinguish the gray matter from the white matter at the boundary line, which became blurred later. Histological changes of brain edema were observed as early as 6 hours after burn, being accompanied by swelling of endothelial cells and peri-vescular astrocytes, and vacuolation took place in neurons at 12 hours after burn, with different degrees of necrosis of capillary endothelium, neurons, and axons. These changes became more marked with elapse of time. The BGS group showed the most obvious changes mentioned above at 24 hours after burn. CONCLUSIONS: The model of the brain edema after severe burn has the feature of both vasogenic edema and cytotoxic edema on the MRI and pathology. Positive MRI findings lagged behind that of the pathomorphological changes.

Animals↗
PubMed1990

Dimethylthiourea reduces ischemic brain edema without affecting cerebral blood flow.

Oxygen free radicals have been implicated as mediators of tissue damage in ischemic brain. We previously demonstrated that the hydroxyl radical scavenger 1,3-dimethyl-2-thiourea (DMTU) reduces infarct size after middle cerebral artery occlusion (MCAO) in rats. The present study was undertaken to determine whether this protection results from a preservation of the CBF. Adult male Sprague-Dawley rats were treated with DMTU (750 mg/kg i.p.) or saline vehicle 1 h before right MCAO. One-half 4, or 24 h after MCAO, animals were killed and samples were taken from the central, intermediate, and outer zones of the MCA distribution of each cortical mantle. Separate groups of animals were used to analyze these samples for water content (wet and dry weight), CBF [( 14C]butanol), or blood-brain barrier permeability [( 3H]alpha-aminoisobutyric acid). CBF was reduced in a graded fashion in the ischemic cortex: 0.169 +/- 0.020, 0.261 +/- 0.017, and 0.435 +/- 0.023 ml/g/min (mean +/- SEM, n = 8) after 4 h in the central, intermediate, and outer zones, respectively. Brain edema was present in a similar pattern, while blood-brain barrier permeability remained normal. Treatment with DMTU significantly reduced brain edema in the central and intermediate zones at both 4 and 24 h. However, CBF in the DMTU-treated animals was identical to that of the vehicle-treated animals. These results suggest that hydroxyl radicals play a role in the development of ischemic brain edema, but the mechanism does not appear to involve a direct effect on CBF.

Animals↗
PubMed1995

Synaptic degenerative changes in human traumatic brain edema. An electron microscopic study of cerebral cortical biopsies.

The cerebral cortex of 9 patients with complicated brain trauma has been examined with the transmission electron microscope to study the distinctive degenerative synaptic changes induced by brain injury and associated vasogenic, moderate or severe, brain edema. The brain injury and the hematogenous edema fluid accumulated in the dilated extracellular space of cerebral cortex neuropil induced swelling and shrinkage of pre- and postsynaptic structures, increased amount of presynaptic axoplasmic granular substance and clumping, enlargement and depletion of synaptic vesicles. In severe brain edema, swollen and shrunken presynaptic endings with discontinuous limiting plasma appeared separated from the postsynaptic structures and detached from glial ensheathment (synaptic disassembly). Post-synaptic shaft dendrites and their spines showed swelling and vacuolization. Fragmen-tation and atrophic changes of spine apparatus were found in the dendritic spines. The clear and dark types of degeneration were observed in most cases examined, in both preand/or postsynaptic structures. Filamentous hypertrophy of presynaptic endings was observed only in two cases. Osmiophylic bodies, necrotic membranes, lipid inclusions and glycogen granules were seen in the synaptic terminals. Disappearance of synaptic densities was evident in some cases. Phagocytosis of isolated presynaptic endings or of the entire synaptic contacts by astrocytes, microglial cells and by non-nervous invading cells, such as monocytes and macrophages, was found.

Adolescent↗
PubMed1993

The role of bradykinin in mediating ischemic brain edema in rats.

BACKGROUND AND PURPOSE: We investigated the hypothesis that bradykinin generation may induce ischemic brain edema in spontaneously hypertensive rats. METHODS: Cerebral ischemia lasting 3 hours was produced by bilateral common carotid artery occlusion in 67 rats. After the ischemic period, the rats were reperfused. Cerebral water content and energy metabolites (adenosine triphosphate, lactate, and pyruvate), as well as plasma and tissue bradykinin, were measured. Additionally, using the same experimental paradigm, bradykinin synthesis inhibitors (aprotinin [n = 7] and soybean trypsin inhibitor [n = 7]) were administered immediately after ischemia induction to determine the relation of bradykinin generation to the progression of ischemic brain edema. RESULTS: Cerebral water content increased during the 3-hour ischemic period, peaked at 30 minutes of reperfusion, and declined thereafter. Bradykinin levels in plasma and tissue rose markedly 30 minutes after reperfusion and fell thereafter. The progressive loss of adenosine triphosphate was mirrored by the rise in lactate. In the treated groups, aprotinin and soybean trypsin inhibitor administration significantly attenuated cerebral edema (p < 0.01 and p < 0.05, respectively). The treated groups also showed less lactate accumulation and more adenosine triphosphate preservation than did the controls. CONCLUSIONS: These results demonstrate that bradykinin levels in plasma and tissue corresponded to cerebral edema progression and that bradykinin suppression decreased edema formation. These novel findings indicate that bradykinin activation augments the progression of ischemic brain edema.

Adenosine Triphosphate↗
PubMed1997

Effect of dl-3-n-butylphthalide on brain edema in rats subjected to focal cerebral ischemia.

The present study evaluated the effect of dl-3-n-butylphthalide(NBP), a novel brain protective agent, on brain edema in rats following focal ischemia. Edema was induced by occluding the right middle cerebral artery (MCAO), producing permanent focal ischemia in the right cerebral hemisphere, which developed ipsilateral brain edema reproducibly. Edema was assessed 24 h after MCA occlusion by determining the brain water content from wet and dry weight measurements, and the sodium, potassium concentrations with ion-selective electrodes. In this model, NBP at the dose of 80, 160 and 240 mg/kg p.o. 15 min after MCAO prevented from brain edema in a dose-dependent manner. A significant reduction of sodium content and an increase in potassium level were observed in all drug-treated groups. It showed that NBP strongly attenuated brain water entry, sodium accumulation and potassium loss. Nimodipine treatment (5 mg/kg s.c.) also reduced brain edema (P < 0.05). The results suggest that a strong anti-edema activity of NBP may play an important role to contribute to the treatment of ischemic damage.

Animals↗
PubMed1988

A model for quantitation of peritumoral brain edema.

A model system is described which is suitable for quantitation of peritumoral brain edema. The temporal development of peritumoral brain edema in dexamethasone-treated rabbits and untreated controls was evaluated following the implantation of VX2 carcinoma cells into the frontal lobe of New Zealand White rabbits. A colorimetric assay of Evans blue (EB) extravasation was used to quantitate edema. Animals receiving a sham tumor injection contained an equal amount of EB compared to control animals. Dexamethasone was found to significantly reduce the extravasation of EB in rabbits with VX2 brain tumors and to delay the onset of neurologic deficits. These results are consistent with events occurring in patients with brain tumors. Studies of new drugs or physiologic aspects of peritumoral edema can be conducted with this model system.

Animals↗
PubMed1990

[Changes in epidural pulse pressure in brain edema following experimental focal ischemia].

It is well known that epidural pulse pressure (PP) increases with rising intracranial pressure (ICP). However, PP at the same ICP is not always identical in various intracranial pathologies. Many authors have investigated PP at increased states of ICP, but few studies related to brain edema have been done. This study was carried out in order to clarify the changes of PP in brain edema following focal ischemia. ICP and PP were measured in two groups of anesthetized dogs; 1) increased volume of CSF by cisternal saline injection (control, n = 5), 2) brain edema caused by focal ischemia (edema, n = 11). Ischemia was induced by electro-coagulation of the right anterior cerebral artery and by clipping the right middle cerebral artery and right internal carotid artery transorbitaly. The brain was recirculated for 6 hours after 2 hours of ischemia. The ischemic areas were identified by Evans blue, triphenyl tetrazolium chloride (TTC) or histological examination. Water content of the brain was measured by the wet-dry weight method. The canine focal ischemic model showed consistent ischemic damage in the caudate nucleus and produced brain edema successfully. PP increased linearly with rising ICP to 35 mmHg, and PP in the edema group was significantly smaller than that in the control group at the same ICP value. The slopes of the regression equation of ICP and PP were significantly different between the edema and control group (edema: 0.061 +/- 0.030, control: 0.107 +/- 0.015, mean +/- SD, p less than 0.01). These results suggest that PP is easily affected by ischemic brain edema.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗