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Query: UMLS:C0085584 (encephalopathy)
 18,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 13-year-old girl with osteosarcoma and pulmonary metastases developed life-threatening renal toxicity, encephalopathy, and bone marrow failure following high dose methotrexate therapy. After successful treatment, high dose methotrexate therapy was continued without further problems. Recommendations for the prevention and the current management of methotrexate toxicity are discussed.
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PMID:[(Management of acute toxicity after high dose methotrexate therapy)]. 39 13

Two children with osteosarcoma are presented in whom Wernicke encephalopathy with vomiting occurred during the chemotherapy. One of the children died with symptoms of toxic cardiomyopathy. Autopsy revealed Wernicke encephalopathy. The other child had similar symptoms (ocular signs, ataxia, somnolence). Parenteral thiamine had been given and after this therapy the child recovered from the encephalopathy. The authors emphasize the importance of the recognition of this neurological disorder occurring rarely in childhood: it can be cured with parenteral thiamine. Without thiamine treatment this condition is lethal.
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PMID:[Wernicke encephalopathy in childhood osteosarcoma]. 140 86

The mechanism of the transient encephalopathy induced by high dose systemic administration of methotrexate (HDMTX) is unknown. Metabolic and vascular hypothesis have been formulated but convincing evidence is lacking. We report the first case of vascular disturbances (thinness of cortical arteries on angiography, reversible fall down of cerebral flow and increase of carotid resistance) in a young Algerian patient treated for an osteogenic osteosarcoma. This observation might lead to the exploration by non invasive and easily repeatable techniques of the cerebral vascular dynamic in patients submitted to HDMTX and thus contributed to the elucidation of the mechanism and to the prevention of these neurological side effect.
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PMID:Cerebral arterial disturbances in a transient encephalopathy induced by methotrexate. 816 55

Defects of the respiratory chain carrying out oxidative phosphorylation (OXPHOS) are the biochemical hallmark of human mitochondrial disorders. Faulty OXPHOS can be due to mutations in either nuclear or mitochondrial genes, that are involved in the synthesis of individual respiratory subunits or in their post-translational control. The most common mitochondrial disorder of infancy and childhood is Leigh's syndrome, a severe encephalopathy, often associated with a defect of cytochrome c oxidase (COX). In order to demonstrate which genome is primarily involved in COX-deficient (COX(-))-Leigh's syndrome, we generated two lines of transmitochondrial cybrids. The first was obtained by fusing nuclear DNA-less cytoplasts derived from normal fibroblasts, with mitochondrial DNA-less (rho degree) transformant fibroblasts derived from a patient with COX(-))-Leigh's syndrome. The second cybrid line was obtained by fusing rho degree cells derived from 143B.TK- human osteosarcoma cells, with cytoplasts derived from the same patient. The first cybrid line showed a specific and severe COX(-) phenotype, while in the second all the respiratory chain complexes, including COX, were normal. These results indicate that the COX defect in our patient is due to a mutation of a nuclear gene. The use of cybrids obtained from 'customized', patient-derived rho degree cells can have wide applications in the identification of respiratory chain defects originated by nuclear DNA-encoded mutations, and in the study of nuclear DNA-mitochondrial DNA interactions.
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PMID:Nuclear DNA origin of cytochrome c oxidase deficiency in Leigh's syndrome: genetic evidence based on patient's-derived rho degrees transformants. 858 77

The cases of three children, 16, 12, and 12 years of age, who suffered sudden confusional state and cortical blindness lasting 12 to 30 minutes while under treatment with high-dose methotrexate, cyclophosphamide, and dactinomycin for a lower limb osteosarcoma are reported. Transient neuropsychologic deficits arose after the acute phase of treatment: left hemispatial neglect and constructive apraxia (Patient 1); constructive apraxia (Patient 2); and constructive apraxia and alexia without aphasia (Patient 3). The three patients recovered completely from all their deficits within the time frame of 3 hours to 2 weeks. Arterial hypertension and hypomagnesemia were found during the acute phase in all patients. In Patients 2 and 3, magnetic resonance imaging revealed increased parieto-occipital T(2) signal involving gray and white matter. In Patients 1 and 2, HmPAO-SPECT revealed parieto-occipital hypoperfusion that resolved a few days later. The alterations detected by neuroimaging were concurrent with the appearance and disappearance of the clinical symptoms. Such transient acute episodes have been named occipital-parietal encephalopathy. On the basis of our clinical, laboratory, and neuroimaging findings, an explanation for the origin of this syndrome, a migrainelike mechanism, triggered by chemotherapy-induced hypomagnesemia, is proposed.
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PMID:Transient posterior encephalopathy induced by chemotherapy in children. 1127 65

Chloroacetaldehyde, a metabolite of the anticancer drug ifosfamide, may be responsible for serious adverse effects like encephalopathy in ifosfamide chemotherapy. In this study, we demonstrate that chloroacetaldehyde, but not ifosfamide, induces cell death in human osteosarcoma Saos-2 cells and we investigated the mechanism by which this occurs. Chloroacetaldehyde above 30 micromol/l induced significant cell death in a time-dependent manner. Thiol compounds such as N-acetyl cysteine, glutathione and dithiothreitol protected the cells against chloroacetaldehyde-induced cell death, although other nonthiol compounds and the antioxidative enzymes superoxide dismutase and catalase did not, suggesting that reactive oxygen species might not mediate cell death. In cells exposed to chloroacetaldehyde, levels of both total thiols and glutathione were significantly reduced. Chloroacetaldehyde also collapsed the mitochondrial membrane potential of these cells, induced the release of cytochrome c from mitochondria to the cytosol and significantly reduced cellular ATP levels during the course of death. The mitochondrial potential collapse was also prevented by thiol compounds. Flow cytometric analyses by means of annexin-V and propidium iodide double staining and immunofluorescence staining of active caspase-3 revealed that cells subjected to a lethal dose of chloroacetaldehyde displayed features characteristic of necrosis and that caspase-3 was not activated in response to chloroacetaldehyde. Taken together, these findings suggest that Saos-2 cells exposed to chloroacetaldehyde die by necrosis resulting from a decrease in intracellular thiols, disruption of the mitochondrial membrane potential and the depletion of cellular ATP.
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PMID:Necrotic pathway in human osteosarcoma Saos-2 cell death induced by chloroacetaldehyde. 1741 23

Methotrexate (MTX) is a major cause of treatment-related acute neurotoxicity. We report on clinical and imaging findings of reversibly restricted diffusion in a patient with transient encephalopathy after high dose MTX therapy for osteosarcoma. During the chemotherapy, a 19-year-old man was introduced for the evaluation of consciousness disturbance. Neurological examination revealed confusion, inability of speak at the onset On next day, there were still difficulties in swallowing and phonation, and furthermore deep tendon reflexes were hyperactive in bilateral lower limbs with positive Babinski responses bilaterally. By the 6th day, findings at neurological examination were completely normal. Initial imaging on presentation was performed using MRI. Diffusion weighted MRI clearly indicated areas of restricted diffusion within both centrum semiovale. These abnormalities were confirmed by the diffusion tensor (DT) technique (ADC and FA map). The follow-up MRI examinations using same protocol showed resolution of the ADC and FA abnormalities but increasing T2-signal changes. Neither contrast enhancement nor atrophy was encountered. Early detection of MTX white matter injury by DT image has the potential to alert the oncologist and neurologist to this event and provide a technique by which treatment of neurotoxicity can be monitored.
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PMID:[Case of methotrexate encephalopathy: findings on diffusion tensor image and correlation with clinical outcome]. 1751 Dec 73

MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) is commonly associated with the A3243G mitochondrial DNA (mtDNA) mutation encoding the transfer RNA of leucine (UUR) (tRNA (Leu(UUR))). The pathogenetic mechanisms of this mutation are not completely understood. Neuronal functions are particularly vulnerable to alterations in oxidative phosphorylation, which may affect the function of the neurotransmitter glutamate, leading to excitotoxicity. In order to investigate the possible effects of A3243G upon glutamate homeostasis, we assessed glutamate uptake in osteosarcoma-derived cytoplasmic hybrids (cybrids) expressing high levels of this mutation. High-affinity Na(+)-dependent glutamate uptake was assessed as radioactive [(3)H]-glutamate influx mediated by specific excitatory amino acid transporters (EAATs). The maximal rate (V(max)) of Na(+)-dependent glutamate uptake was significantly reduced in all the mutant clones. Although the defect did not relate to either the mutant load or magnitude of oxidative phosphorylation defect, we found an inverse relationship between A3243G mutation load and mitochondrial ATP synthesis, without any evidence of increased cellular or mitochondrial free radical production in these A3243G clones. These data suggest that a defect of glutamate transport in MELAS neurons may be due to decreased energy production and might be involved in mediating the pathogenic effects of the A3243G mtDNA mutation.
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PMID:MELAS mitochondrial DNA mutation A3243G reduces glutamate transport in cybrids cell lines. 1845 61

Posterior reversible encephalopathy syndrome (PRES) is a clinico-neuroradiologic disease entity represented by characteristic magnetic resonance image (MRI) findings of subcortical/cortical hyperintensity in T2-weighted sequences, more often observed in parieto-occipital lobes, accompanied by clinical neurologic alterations. PRES is a rare central nervous system complication in childhood hematologic-oncologic patients and shows very different neurologic symptoms between patients, from numbness on extremities to generalized seizure. The etiology of PRES was not well known until these days. In this study, 8 patients with PRES were reviewed, retrospectively. There were 4 patients with acute lymphocytic leukemia, 1 with aplastic anemia, and 3 with solid tumors (1 patient each for neuroblastoma, Ewing sarcoma, and osteosarcoma). Allogeneic stem cell transplantation was performed in 2 patients. Immunosuppressive agents such as tacrolimus and cyclosporine A were used in 3 patients. One neuroblastoma patient was in immediate postoperative status. All patients experienced seizure attacks of different types and showed typical MRI findings. Follow-up MRIs revealed significant improvements. From this review, we might consider chemotherapy and surgery as additive causes for PRES other than immunosuppressive agents. Therefore, careful examination of the patients receiving chemotherapy and surgery was needed to find out this uncommon but good prognostic complication.
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PMID:Posterior reversible encephalopathy syndrome in childhood with hematologic/oncologic diseases. 1956 46

Methotrexate, administered for treatment of pediatric and adult malignancies, is a direct renal toxin, which can lead to renal dysfunction, decreased methotrexate clearance, elevated methotrexate concentrations, and systemic toxicity. Although plasma methotrexate concentrations have been shown to decline precipitously after a single dose of glucarpidase, this drug is investigational and available only through compassionate use. Therefore, alternative treatments for methotrexate removal may be required. We describe a 13-year-old girl (body surface area 1.2 m(2)) with osteosarcoma who was treated with high-dose methotrexate 12 g/m(2) infused over 4 hours. Forty-eight hours after the infusion, her plasma methotrexate concentrations were elevated at 446 micromol/L. She exhibited severe signs of methotrexate toxicity, including encephalopathy, liver failure, and acute kidney injury, and could not tolerate conventional hemodialysis. Over the next 12 days, the patient was treated with continuous venovenous hemodialysis (CVVHD), single-pass albumin dialysis (SPAD), continuous venovenous hemodiafiltration (CVVHDF), and glucarpidase to enhance methotrexate elimination. Compared with standard CVVHD, SPAD did not significantly increase methotrexate removal as measured by elimination half-life and methotrexate saturation coefficient. The highest clearance rate among extracorporeal therapies was achieved by CVVHDF, with an effluent rate of 4950 ml/hour. The patient's clinical condition steadily improved, and all extracorporeal therapies were stopped 168 hours after methotrexate administration. The patient was discharged home and continued with chemotherapy, including methotrexate, which was dosed based on iothalamate glomerular filtration rates on the day before infusion. Although extracorporeal treatments appeared to enhance methotrexate clearance, the administration of glucarpidase resulted in the most rapid percentage decline (86%) in methotrexate concentration. Until glucarpidase is readily available, intermittent hemodialysis should be used to enhance methotrexate clearance. If the patient is unable to tolerate hemodialysis, use of CVVHDF with maximum effluent rates will enhance methotrexate clearance.
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PMID:Treatment of methotrexate intoxication with various modalities of continuous extracorporeal therapy and glucarpidase. 2003 Apr 80


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