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

Following reports of a Reye-like syndrome in children resulting from Margosa oil (MO) ingestion, we administered MO to laboratory rats in an attempt to produce an animal model of Reye's syndrome. Male rats were injected intraperitoneally with either MO or corn oil and observed for clinical signs of a toxic response. After 15 h the animals were administered a second dose and the MO-treated animals developed florid neurological symptoms. The animals were then sacrificed and blood samples were analyzed for glucose, ammonia, aspartate aminotransferase, and alanine aminotransferase. Sections of liver, kidney, and brain were examined by light microscopy after Sudan black B, hematoxylin and eosin, and periodic acid-Schiff staining. Liver was additionally examined by electron microscopy. Liver samples were analyzed for hepatic enzyme levels and brain samples were analyzed for water content. There were greatly increased levels of ammonia, aspartate aminotransferase, and alanine aminotransferase and decreased glucose levels in the blood of MO-treated animals. Light microscopy of MO-treated livers revealed fatty infiltration, granularity of the cytoplasm with normal nuclei, and glycogen depletion; electron microscopy revealed mitochondrial pathology in the livers of MO-treated animals. There were no significant morphological changes in brain or kidney specimens although the kidneys did show some fatty infiltration. Hepatic mitochondrial enzyme levels were unchanged and there was no increase in brain water content in the MO-treated animals. Thus, many of the abnormalities seen in Reye's syndrome were seen in this model; however, there were no hepatic enzyme changes despite altered mitochondrial morphology and no evidence of cerebral edema despite a florid encephalopathy. Nonetheless, this model may have important implications for the understanding of the pathogenetic mechanisms of this Reye-like syndrome and, perhaps, Reye's syndrome.
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PMID:Investigation of an animal model of a Reye-like syndrome caused by Margosa oil. 408 Apr 57

Lead encephalopathy was induced in suckling rats by administering lead to the mother. The brains were studied by light and electron microscopy, and the results were compared with observations in the human disease as well as in cases of cerebral ischemia in children. In their severe forms, both human and experimental lead encephalopathies are characterized by exudative extracellular edema and perivascular PAS-positive globules. The latter consist of osmiophilic non-membrane-limited cytoplasmic inclusions located, in the rat exclusively and in the human predominantly, in perivascular astrocytes. Intervascular strands are also found in both forms of the disease. In the rat these consist of basement membrane surrounding endothelial cytoplasm. Chemically, experimental lead encephalopathy with morphologically demonstrable edema is associated with an increase in brain water, sodium and serum albumin. Relative to the serum concentration, the increase in water is disproportionately greater than the sodium or albumin. There were no demonstrable changes in chloride or potassium.
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PMID:Electron microscopic and chemical studies of the vascular changes and edema of lead encephalopathy. A comparative study of the human and experimental disease. 435 30

When normal individuals eat 0.33 g protein N/kg body weight (BW)((3/4)) per day, they excrete 10-15 mg urea N/h per kg BW((3/4)). If they now ingest (at 0 h) 0.27 (dose A), 0.40 (dose B), 0.53 (dose C), 0.94 (dose D), or 1.33 (dose E) g protein N/kg BW((3/4)) (in the form of casein, ovalbumin, or lactalbumin), the rate of urea N excretion accelerates within 4 h. At dose C a maximal rate of urinary urea N excretion (MRUE) is reached, which averages 55 mg urea N/h per kg BW((3/4)) and which persists for 16 h. Higher doses of protein do not further accelerate urea excretion, but prolong the duration of MRUE to 28 h (after dose E). Blood urea N (BUN) rises by 7-20 mg/100 ml during the first 8 h after dose C to E, and remains stable within +/-5 mg/100 ml during the ensuing 8-28 h of MRUE. Each increment of protein above dose C causes a further increment in plasma alpha-amino N. During infusion of free amino acids at a rate of 110 or 165 mg amino acid N/h per kg BW((3/4)) for 12 h, rate of urea excretion increases to the MRUE value produced by dose C-E of oral protein.These findings indicate that MRUE corresponds to a period of maximal rate of urea synthesis (MRUS). MRUS is greater than MRUE because one fraction of newly formed urea is hydrolyzed in the gastrointestinal tract, and another fraction may accumulate temporarily in body water during the MRUE period. Oral neomycin reduces the proportion of urea hydrolyzed in the gut to less than 20%; its extent is measured by recovery in the urine of a tracer dose of [(14)C]urea injected intramuscularly during determination of MRUE. Accumulation of urea in body water is estimated from increment in BUN during the period of MRUE measurement (8-24 h after dose E of casein) and from body water measured with (3)H(2)O. Then MRUS is calculated as: ([mg urea N excreted between 8 and 24 h after dose E] + [BUN at 24 h - BUN at 8 h] x [body water]) x (100/% recovery [(14)C]urea) x (1/kg BW((3/4))) x (1/16 h).MRUS in 10 normal subjects averaged 65 mg urea N/h per kg BW((3/4)) (range 55-76), and in 34 cirrhotics 27 mg urea N/h per kg BW((3/4)) (range 6-64). Among 19 cirrhotic patients fed 40, 60, 80, or 100 g protein daily for successive 10 day periods, the occurrences of hyperammonemia, hyperaminoacidemia, and encephalopathy at each level of protein intake were inversely related to MRUS value.
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PMID:Maximal rates of excretion and synthesis of urea in normal and cirrhotic subjects. 472 56

In a necropsy study of brain water, sodium, and potassium concentrations is newborn infants, abnormalities were found in 10 out of 16 cases who were severely asphyxiated at birth. It is concluded that, although frank cerebral cortical necrosis is not often recognizable in perinatal deaths, early anoxic-ischaemic cerebral damage is frequent after intrapartum asphyxia. Diffuse cerebral swelling was associated with marked electrolyte disturbances and may be regarded as a feature of anoxic-ischaemic encephalopathy in asphyxiated newborn infants.
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PMID:Water and electrolyte abnormalities in the human brain after severe intrapartum asphyxia. 483 46

Findings of the serial EEGs of 9 children involved in fresh water near-drowning were correlated with neurological signs and final outcome. Our observations revealed that in young near-drowning victims there is a distinct evolution of the EEG which differs considerably from any stereotyped classification outlined for other types of encephalopathies. In patients with a poor clinical outcome, the early phase of near-drowning encephalopathy was characterized electrically by diffuse delta waves, often with alpha or beta frequencies superimposed (alpha-delta and beta-delta pattern). Additional features included poor sleep-waking differentiation and abnormal reactivity. Repetitive focal or multifocal biphasic or triphasic wave forms occurred exclusively in the group with a fatal outcome. The intermediate phase of the encephalopathy was signaled by an attenuation of all fast frequencies (alpha and beta rhythms), enhancement of delta activity, and disappearance of sleep parameters (if present in the earlier recordings). Finally, a modified burst suppression pattern occurred as a late EEG evolution in an encephalopathy of complex and protracted nature.
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PMID:Electroencephalographic correlates of near-drowning encephalopathy in children. 617 90

To anticipate the hepatic vascular response to portacaval anastomosis, we studied portal pressure during diversion of portal blood through a temporary extracorporeal umbilical vein to saphenous vein shunt. The relationship of portal pressure to shunted flow was approximately linear. In five schistosomiasis patients (controls) portal diversion to 1,250 ml/min gave portal pressure-shunted flow curve slopes ranging from 0.13 to 0.57 cm water/100 ml per min (0.31+/-0.18, mean+/-SD). In 17 cirrhotic patients with portal hypertension a continuum of slopes was observed from within mean+/-2 SD of control (type A) to larger slopes (type B) indicating failure of portal pressure regulation. When portal flow was augmented by shunting from saphenous vein to portal vein, cirrhotic patients who had slopes less than mean+/-2 SD of controls during diversion (type A) exhibited a compliant system with small increases in portal pressure, whereas type B patients had significantly greater pressure increases. Selective investigations suggested that changes in portal pressure provoked compensatory changes in hepatic arterial blood flow that tended to maintain portal pressure at a set point. Type B patients demonstrated failure of this mechanism to varying degrees.After end-to-side portacaval shunt, seven type A cirrhotic patients maintained residual intrahepatic venous pressure unchanged from prior portal pressure, whereas six type B patients had a significant decrease. Residual intrahepatic venous pressure was measured after portacaval shunt in 40 cirrhotic patients who were followed for as long as 9 yr (median survival 4.0 yr). The 13 patients who developed chronic encephalopathy had significantly lower pressure (21.1+/-4.4 cm, mean+/-SD) and shorter survival (median 0.6 yr) than the other 27 patients (32.6+/-5.3 cm, 5.0 yr). The preoperative estimation of portal pressure-diverted portal flow curve slope anticipates the hepatic vascular response to portacaval anastomosis and identifies a group of patients in whom loss of portal blood flow results in a low residual intrahepatic venous pressure that is associated with early death and chronic encephalopathy.
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PMID:Effect of portal venous blood flow diversion on portal pressure. 625 Nov 12

Twelve patients with chronic renal failure, on maintenance hemodialysis have a stereotyped illness. The dialysate was made up from a high level aluminium tap water. After having been on haemodialysis for 10 to 12 months, they suffer from more and more acute osteodystrophic, osteomalacic symptoms. Then, distinctive EEG abnormalities appear. These first symptoms allow an early diagnosis of the progressive dialytic encephalopathy. The neurological symptoms appear some months later. Eight patients died from this encephalopathy. Four patients are still alive and are, from at least two years, on maintenance haemodialysis with a free aluminium water. In these 4 cases, the evolution of the disease is good: osteomalacic symptoms disappear in a year; the neurological symptoms are still present though transient. EEG abnormalities remain and blood aluminium level is about 100 micrograms/L. These cases show, once more, the significant role of aluminium as an aetiological factor in "progressive dialysis encephalopathy".
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PMID:[Chronological study of signs of myoclonic encephalopathy in hemodialysis patients (author's transl)]. 627 30

One of the most important complication of patients with chronic renal failure is osteodystrophy. This causes skeletal deformities, growth failure, bone pain and decreased physical activity. Osteodystrophy is more frequent among children than uraemic adults. In fact, 50-80% of children with chronic renal failure may occur in metabolic bone disease and the incidence tends to be higher in those children who have been in uraemic state for a long time before starting chronic haemodialysis. Osteodystrophy is a result of: 1) lesions of rickets; 2) lesions of osteitis fibrosa: 3) osteosclerosis. In contrast to adult, metastatic calcifications are virtually never observed in uraemic children. Hyperphosphoraemia, that is secondary to the reduction of G.F.R., may be the principal responsible of hyperparathyroidism that is the main cause of osteodystrophy. Hyperparathyroidism is also maintained and increased by deficit of 1,25(OH)2D3 which is responsible for lesions of rickets. Haemodialysis may markedly improve osteitis fibrosa and it is efficacious in reversing the mineral defect. Dialysate calcium concentration should be maintained at approximately 3,5 mEq/l. In this case we can raise serum calcium. On the contrary dialysate has to be lacking in phosphorus to correct hyperphosphoraemia. It must be noted that we have to prepare a dialysate with deionized water lacking in aluminum to avoid encephalopathy compliance.
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PMID:[Osteodystrophy in children with chronic renal insufficiency in dialysis therapy]. 628 42

In 25 (33.8%) of 74 chronically haemodialysed patients a distinct osteopathy with bone pain, spontaneous fractures, arthralgias and weakness of the muscles due to dialysis was present. In comparison to a group without complaints the duration of the dialysis was longer by 6 months, the mineral contents of the bones was decreased in 38%, in the comparative group in 22%. A progressive demineralisation was found in 46%, in the comparative group in 20%. Hypercalcaemias under vitamin D2 caused a therapy resistance. In 1 exemplary case (type IIc, PTH 0.3 micrograms/l) in the 3rd year of dialysis a fracture of the neck of the femur took place and an endoprosthesis was implanted. There was a progressive demineralisation of about 16%. The suspicion of a typical combination with an encephalopathy due to dialysis did not confirm itself. A pseudocyst in the brain was found. The differential diagnosis to the hypercalcaemia-induced psychosis in the osteopathy due to dialysis is discussed. In a prophylactic application dihydrotachysterine proved favourable for avoidance of an osteopathy due to dialysis. Parallel to the clinical progressing of the osteopathy due to dialysis a progressive demineralisation could be demonstrated at the peripheral mineral contents of the bones. Extreme losses of minerals appeared from the 4th to the 59th month of dialysis from - 16% to - 37% and from the 22nd to the 87th month from plus 11% to minus 14% of the age-and-sex-specific normal values. Successful transplantations led to the stagnation of the progressive demineralisation, unsucessful transplantations increase them. The influence of the non-refined water for the production of dialysate by possible aluminium intoxications on the development of the osteopathy due to dialysis is discussed.
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PMID:[Dialysis osteopathy with spontaneous fractures, progressive demineralization and therapy resistance]. 635 38

Between 1968 and 1980 fractures occurred in 56 of 284 patients treated by home haemodialysis in the Sheffield area for longer than one year. Patients sustained four times as many fractures while using dialysate prepared with water containing more than 1.0 mumol aluminium per 1 (2.7 micrograms/100 ml) than while using water containing a smaller concentration. When aluminium was removed from water by deionisation the incidence of fractures diminished during the next year and no patient developed dialysis encephalopathy. These findings show that 1.0 mumol/l is a safe maximum concentration of aluminium in water for use in home haemodialysis. It can be detected by the colorimetric aluminium analyses used by many water authorities. When financial resources are limited it is expedient to reserve aluminium analyses by electrothermal atomic absorption for plasma from patients receiving regular haemodialysis. Ingestion of aluminium hydroxide contributes significantly to the increased plasma aluminium concentration of these patients.
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PMID:Water purification and the incidence of fractures in patients receiving home haemodialysis supervised by a single centre: evidence for "safe" upper limit of aluminium in water. 642 63


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