Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0085584 (encephalopathy)
 18,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The findings on magnetic resonance imaging (MRI) or computed tomographic scan in 35 children with acute encephalopathy (AE) induced by infections were categorized into five groups: (1) normal findings (11 cases), (2) normal findings in the acute phase followed by mild brain atrophy (1 case), (3) severe brain edema which developed within 48 hours after the onset of AE (7 cases), (4) diffuse cortical necrosis which appeared around 4 days after the onset of AE (9 cases), and (5) symmetric thalamic lesions (7 cases). Their outcomes were as follows: three cases developed epilepsy in (1) and (2); six died and one had a sequel of severe brain damage (SBD) in (3); all cases survived but had SBD in (4), and four died, one had SBD, and 2 recovered in (5). Serum AST were elevated in 7.7 and 6 cases in (3), (4) and (5), respectively. In all of them, there were more than one case having liver histologies consistent with Reye syndrome.
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PMID:[Clinical studies on 35 patients with infection-related acute encephalopathy]. 961 58

Free radical-mediated injury is implicated in hypoxic-ischemic encephalopathy observed in neonates. We investigated in utero free radical production and injury following hypoxia-ischemia to premature fetal brain utilizing a rabbit model of acute placental insufficiency. Pregnant rabbits at 29 days gestation were randomized to uterine ischemia for 50 minutes (min) (hypoxia) or nonischemic controls. Fetal brains were obtained immediately after ischemia for oxidative and acute-injury markers or 24 hours (h) post-ischemia for histopathology. Nitrotyrosine formation, a marker of NO-derived species such as peroxynitrite, was observed only in hypoxic brains. Hypoxia resulted in a significant increase in nitrogen oxides, lipid peroxidation, and protein oxidation, with a concomitant decrease in total antioxidant capacity, compared with controls. Peroxynitrite addition to brain homogenate increased nitrogen oxides linearly (1:1), although protein carbonyls were unchanged. Concomitantly, in vitro cortical and hippocampal cell viability and ATP levels decreased, with an increase in brain edema in hypoxic brains. Fetuses delivered 24 h post-ischemia had increased hippocampal nuclear karyorrhexis on histology compared with controls. Antioxidant administration (ascorbic acid and Trolox) intraperitoneally ameliorated changes in cellular viability and brain edema. Acute fetal hypoxia-ischemia without reoxygenation results in increased nitrogen and oxygen free radical production that may cause brain injury. The merits of the described model are discussed.
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PMID:Sustained hypoxia-ischemia results in reactive nitrogen and oxygen species production and injury in the premature fetal rabbit brain. 963 Feb 34

Reye syndrome (RS) is an acute encephalopathy in childhood, and is very rare in adulthood. Here we report a 21-year-old woman with RS. Because of her dysmenorrhea, she took 3 tablets of diclofenac sodium (25 mg) per day in 3 divided doses for two days. Two days after the last intake of the medicine, she developed high fever, nausea, vomiting, and disturbance of consciousness with delirium, i.e., acute encephalopathy. She did not have seizure, hemiplegia, or other focal neurological manifestations. The serum GOT level was normal at onset, but in 12 hours dramatically increased up to 8,632 IU/L. The serum bilirubin level was normal. The cerebrospinal fluid revealed normal cell count, and protein. Although the liver biopsy was not performed because of thrombocytopenia, we diagnosed her as an adult case of RS according to the clinical criteria of the Center for Disease Control. In addition to treatment for the brain edema, plasma exchange was performed once treat the encephalopathy at the onset. The next day, her consciousness level and serum GOT level markedly improved. She completely recovered from acute encephalopathy in a week after her admission. In conclusion, diclofenac sodium, as well as aspirin, should be considered as a possible causal agent for RS, and early plasma exchange may be beneficial.
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PMID:[An adult case of Reye syndrome induced by diclofenac sodium, and recovered by plasma exchange]. 974 77

We report a case of reversible encephalopathy syndrome in a 16-year-old girl with acute myelogenous leukemia (AML), who is undergoing during consolidation chemotherapy composed of BH-AC (N4-behenoyl-1-beta-D-arabinofuranosyl cytosine) and idarubicin. On the 6th day of chemotherapy, she was in a drowsy state following generalized tonic clonic seizure lasting 20 minutes. MR images revealed extensive cortical and subcortical white matter brain edema. Alertness returned over the 24 hr following by the discontinuation of BH-AC and intravenous administration of diphenylhydantoin, although she complained of intermittent headaches and visual disturbance. She gradually recovered from these symptoms during subsequent 7 days. Previously noted abnormal signal intensities have nearly disappreared on follow-up MRI obtained on the 22nd day after the first seizure. She was discharged without any neurologic sequela. This case suggests that BH-AC, a derivative of cytosine arabinoside (1-beta-D-arabinofuranosylcytosine) could be a cause of reversible encephalopathy syndrome.
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PMID:Behenoyl cytarabine-associated reversible encephalopathy in a patient with acute myelogenous leukemia. 1010 31

A neonate presented in the first weeks after birth with vomiting. He was unresponsive, with hypotonia, macrocephaly, and lactic acidosis. The cranial computed tomographic scan revealed a hypodense brain, with increased brain volume and extensive cerebral edema. He died at 6 weeks of age; postmortem examination revealed necrotizing encephalopathy with marked brain edema, spongiosis, thalamic necrosis, and basal ganglia calcifications. Enzyme studies of the mitochondrial respiratory chain revealed complex I deficiency in both muscle and liver.
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PMID:Necrotizing encephalopathy and macrocephaly with mitochondrial complex I deficiency. 1032 81

1,3,5-Trinitrobenzene (TNB) is a soil and water contaminant at certain military installations. Encephalopathy in rats given 10 daily oral doses of TNB has been reported. The lesion was bilaterally symmetric vacuolation and microcavitation in the cerebellar roof nuclei, vestibular nuclei, olivary nuclei, and inferior colliculi. The contribution of the blood-brain barrier (BBB) in the genesis of these lesions remains uncertain. One of the main goals of the present work was to evaluate the functional state of the BBB. Male Fischer 344 rats (five rats/group) were euthanatized after four, five, six, seven, eight, or 10 daily doses of TNB (71 mg/kg). A different set of rats (five rats/group) was allowed to recover for 10 or 30 days after receiving 10 doses of TNB. Integrity of the BBB was assessed by immunohistochemical staining for extravasated plasma albumin on paraffin-embedded sections. Rats euthanatized after four to eight doses had no lesions, and albumin extravasation in the susceptible regions of the brain was minimal. Rats receiving 10 daily doses of TNB had bilaterally symmetric vacuolation and microcavitation in the cerebellar nuclei, vestibular nuclei, and inferior colliculi in association with multifocal, often confluent foci of extravasated albumin in susceptible nuclei. Albumin was present in vascular walls, extracellular space, and neurons. Immunoreactivity in neurons was of two types: cytoplasmic staining representing pinocytic uptake and homogeneous staining of the entire neuron (nucleus and cytoplasm) due to uncontrolled albumin leakage through the damaged cell membrane. In rats allowed to recover for 10 days, the microcavitated foci were infiltrated by glial and gitter cells. Albumin immunoreactivity was present as extracellular granular debris, and neuronal staining (for albumin) was mild. In rats allowed to recover for 30 days, immunoreactivity to albumin was not seen. This study demonstrates that TNB-mediated tissue damage is accompanied by breakdown of the BBB. The presence of vacuolation and associated extravasated serum proteins in TNB-treated rats is an indication of vasogenic brain edema, which appears to be a critical event in TNB toxicity. Additional studies are needed to determine the reason for selective regional vulnerability and brain microvascular susceptibility to TNB.
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PMID:Neurotoxicity of 1,3,5-trinitrobenzene (TNB): immunohistochemical study of cerebrovascular permeability. 1033 29

Without transplantation, approximately 50-90% of all patients with fulminant hepatic failure (FHF) die. This poor outcome is due in part to the absence of an appropriate animal model, which would allow for a greater understanding of the pathophysiology of this syndrome. Given the reports of liver injury in humans and livestock fed cycad palm nuts on the island of Guam, we hypothesized that the active ingredient azoxymethane (AOM) could cause FHF. We therefore evaluated AOM in C57BL/6J mice. Histologically, we observed microvesicular steatosis 2 h, sinusoidal dilatation 4 h, and centrilobular necrosis 20 h after AOM administration, and transmission electron microscopy showed that this agent causes mitochondrial injury. FHF was associated with all four stages of encephalopathy, as well as by a prodromal period of decreased eating and drinking lasting approximately 15 h before the development of stage I encephalopathy (i.e., loss of scatter reflex). Late encephalopathy was associated with increased arterial ammonia, decreased serum glucose, and evidence of brain edema (astrocyte swelling). We show that AOM-induced FHF is highly reproducible, without evidence of lot-to-lot variability, and is dose dependent. These findings therefore suggest that AOM is an excellent agent for the study of FHF, as well as indicate that Guamanian FHF may be due to AOM found in unwashed cycad palm nuts.
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PMID:Azoxymethane-induced fulminant hepatic failure in C57BL/6J mice: characterization of a new animal model. 1044 60

Brain edema sufficient to cause intracranial hypertension and brain herniation remains a major cause of mortality in acute liver failure (ALF). Studies in experimental animal models of ALF suggest a role for ammonia in the pathogenesis of both encephalopathy and brain edema in this condition. As part of a series of studies to evaluate the therapeutic efficacy of ammonia-lowering agents, groups of rats with ALF caused by hepatic devascularization were treated with L-ornithine-L-aspartate (OA), an agent shown previously to be effective in reducing blood ammonia concentrations in both experimental and human chronic liver failure. Treatment of rats in ALF with infusions of OA (0.33 g/kg/h, intravenously) resulted in normalization of plasma ammonia concentrations and in a significant delay in onset of severe encephalopathy. More importantly, brain water content was significantly reduced in OA-treated rats with ALF. These protective effects of OA were accompanied by increased plasma concentrations of several amino acids including glutamate, gamma-aminobutyric acid (GABA), taurine, and alanine, as well as the branched-chain amino acids, leucine, isoleucine, and valine. Increased availability of glutamate following OA treatment provides the substrate for the major ammonia-removal mechanism (glutamine synthetase). Plasma (but not cerebrospinal fluid) glutamine concentrations were increased 2-fold (P <.02) in OA-treated rats, consistent with increased muscle glutamine synthesis. Direct measurement of glutamine synthetase activities revealed a 2-fold increase following OA treatment. These findings demonstrate a significant ammonia-lowering effect of OA together with a protective effect on the development of encephalopathy and brain edema in this model of ALF.
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PMID:L-ornithine-L-aspartate lowers plasma and cerebrospinal fluid ammonia and prevents brain edema in rats with acute liver failure. 1046 68

There is increasing evidence to suggest that hepatic encephalopathy in acute liver failure is the result of altered glutamatergic function. In particular, the high affinity uptake of glutamate is decreased in brain slices and synaptosomes from rats with acute liver failure as well as by exposure of cultured astrocytes to concentrations of ammonia equivalent to those reported in brain in acute liver failure. Both protein and gene expression of the recently cloned and sequenced astrocytic glutamate transporter GLT-1 are significantly reduced in the brains of rats with acute liver failure. Decreased expression of GLT-1 in brain in acute liver failure results in increased extracellular brain glutamate concentrations which correlates with arterial ammonia concentrations and with the appearance of severe encephalopathy and brain edema in these animals. Ammonia-induced reductions in expression of GLT-1 resulting in increased extracellular glutamate concentrations could explain some of the symptoms (hyperexcitability, cerebral edema) characteristic of hepatic encephalopathy in acute liver failure.
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PMID:Evidence for an astrocytic glutamate transporter deficit in hepatic encephalopathy. 1055 80

Cerebral vascular accidents are one of the causes of morbidity and mortality in children with diabetic ketoacidosis. We investigated the possible occurrence of asymptomatic cerebrovascular infarcts and the course of subclinical brain edema in six patients. Neurologic examinations and computer analysis of magnetic resonance imaging were performed immediately after, and again at 14 days after, correction of DKA. None of the patients had clinical evidence of a neurologic deficit. Neither radiologic evaluation nor computer analysis of MRI identified changes indicating asymptomatic ischemic events. However, a computer analysis of the MRI identified a significant increase of the total ventricle area between Day one and Day 14. Our study does not establish whether this change is a return to the baseline prior to DKA or a new baseline, representing an early manifestation of diabetic encephalopathy.
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PMID:Computer analysis of magnetic resonance imaging of the brain in children and adolescents after treatment of diabetic ketoacidosis. 1061 55


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