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)

Sepsis is a major catabolic insult resulting in modifications in carbohydrate and fat energy metabolism, and leading to increased muscle breakdown and nitrogen loss. Insulin resistance, which develops in sepsis, decreases glucose utilization, but plasma insulin levels are sufficiently elevated to prevent lipolysis, resulting in a further energy deficit. The availability of fuels in sepsis is therefore limited, and the body resorts to muscle breakdown, gluconeogenesis, and amino acid oxidation for energy supply. Previous work has not defined, however, the exact alterations in amino acid metabolism. Therefore, the following studies were undertaken. Blood samples were drawn from fifteen patients in whom the diagnosis of sepsis was clinically established; the samples were analyzed for amino acid, beta-hydroxyphenylethanolamines, glucose, insulin and glucagon concentrations. The plasma amino acid pattern observed was characterized by an increase in total amino acid content, due mainly to high levels of the aromatic amino acids (phenylalanine and tyrosine) and the sulfur-containing amino acids (taurine, cystine and methionine). Alanine, aspartic acid, glutamic acid and proline were also elevated, but to a lesser degree. The branched chain amino acids (valine, leucine and isoleucine) were within normal limits, as were glycine, serine, threonine, lysine, histidine and tryptophan. Those patients who did not survive sepsis had higher levels of aromatic and sulfur-containing amino acids as compared to those patients surviving sepsis. On the other hand, those patients surviving sepsis had higher levels of alanine and the branched chain amino acids. In a second group of five patients with overwhelming sepsis accompanied by a state of metabolic encephalopathy, a parenteral nutrition solution consisting of 23% dextrose, and an amino acid formulation enriched with branched chain amino acids was administered. In these five patients, normalization of the plasma amino acid pattern and reversal of encephalopathy was observed. The following sequence of events may be postulated: The septic patient develops insulin resistance in the peripheral tissues, primarily muscle, while the adipose tissue is much less affected. The insulin resistance and the inability to utilize fat leads to increased muscle proteolysis. Muscle breakdown results in release into the blood of enormous amounts of various amino acids; the muscle itself is able to oxidize the branched chain amino acids, supplying the muscles' own energy requirements and alanine for gluconeogenesis. The extensive muscle proteolysis coupled with relative hepatic insufficiency occurring early in sepsis results in the appearance in the plasma of high levels of most of the amino acids present in muscle, particularly the aromatic and the sulfur-containing amino acids. The outcome of patients with sepsis might be positively affected by combined therapy with glucose, insulin and branched chain amino acids.
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PMID:Amino acid derangements in patients with sepsis: treatment with branched chain amino acid rich infusions. 9 98

Sepsis is a major catabolic insult resulting in a peripheral energy deficit which is made up in part by increased breakdown of lean body mass and oxidation of amino acids, principally the branched chain amino acids. The prognosis in any given case of sepsis is difficult to predict, but should theoretically be related to the degree of disturbance in peripheral energy deficit, which may in turn, be related to plasma amino acid pattern. In order to study whether this hypothesis was correct, plasma amino acids and some of their metabolic byproducts, the beta-hydroxyphenylethanolamines, were studied in 25 septic patients, and were used as discriminant variables in a series of computer performed discriminant analyses and multiple regressions. The two functions tested were the degree of metabolic septic encephalopathy as a determinant of the severity of sepsis and the final outcome in the septic patient. Plasma amino acid patterns exhibited elevated levels of the aromatic and sulfur containing amino acids, phenylalanine, tryosine, tryptophan, methionine, cysteine, and taurine, normal concentrations of alanine, and low normal concentrations of the branched chain amino acids, valine, leucine and isoleucine. Arginine levels, as previously noted, were very low. Patients not surviving the septic episode exhibited higher concentrations of aromatic and sulfur containing amino acids, while patients surviving sepsis had higher concentrations of the branched chain amino acids and arginine. When the degree of encephalopathy as a determinant of the severity of sepsis and step wise discriminant analysis with multiple crescent techniques were used, the best discriminant function between patients with and without encephalopathy was found to result from the interaction of cysteine, methionine, phenylalanine, isoleucine, leucine, and valine. These amino acids gave a correct classification in 82% of patients with no encephalopathy, and 80% of patients with septic encephalopathy. When the same amino acids were used for the discriminant analysis for patients dying of sepsis and patients surviving, the best discriminant function was achieved by using plasma concentrations of alanine, cysteine, methionine, isoleucine, arginine, tyrosine and phenylalanine resulting in 91% of the nonsurvivors, and 79% of the survivors correctly classified. The results suggest a close and significant relationship between the deranged energy metabolism and muscle protein breakdown in sepsis, and the outcome. This further suggests a central role for certain amino acids in perhaps predicting the severity of sepsis and its outcome.
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PMID:Plasma amino acids as predictors of the severity and outcome of sepsis. 38 83

Uptake of various amino acids was studied in slices from brain regions of rats four weeks after portocaval anastomosis. No differences of the inulin compartment were observed between control and experimental animals. After 60-minutes incubation, uptake showed an overall pattern of diminution. This was more evident for some amino acids: valine, methionine, and lysine exhibited a lowering of about 30%, which was fairly uniform in the four tested regions; others showed a regional decrease-- alanine in pons-medulla, phenylalanine in cerebellum, histidine and GABA in mesodiencephalon. This decrease did not seen to be related to transport classes. The restricted entry of amino acids into brain cells in portocaval encephalopathy is somewhat difficult to explain; a decreased rate of protein synthesis may be of some importance, but other factors, such as a "carrier" impairment, effects on release and on amino acid metabolism, may also be involved.
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PMID:Cerebral amino acid levels and uptake in rats after portocaval anastomosis: I. Regional studies in vitro. 46 64

Blood substrate and hormone concentration were determined in 16 children with Reye syndrome prior to and following administration of hypertonic glucose. Baseline concentrations of lactate, pyruvate, alanine, glutamine, glutamate, proline, hydroxyproline, lysine, and aspartate were elevated (p less than 0.01), whereas citrulline and arginine were low. All substrate concentrations were below or within the normal range following 36 hours of therapy except those of lactate, pyruvate, and aspartate. Urea nitrogen excretion was reduced (p less than 0.05) on the second day of therapy. Plasma concentrations of insulin and growth hormone increased and glucagon decreased during the first day. Cortisol remained elevated throughout the study period. We conclude that the high circulating concentrations of substrates are the result of both increased mobilization and decreased clearance and that hypertonic glucose infusion suppresses substrate mobilization. A primary abnormality of the mitochondria could explain the metabolic perturbations that occurred. A possible relationship between the encephalopathy in this disorder and an insult to both brain and brain capillary mitochondria is discussed.
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PMID:Metabolic response to hypertonic glucose administration in Reye syndrome. 66 61

In hepatic coma as well as diabetic coma severe disturbances occur in the amino acid metabolism. The defect lies in completely different levels which result two different plasma aminograms (PAG). In 24 patients with hepatic encephalopathy stage III-IV (7 patients with acute and 17 with chronic liver failure) the PAG were evaluated. The determination of the plasma amino acids (PAA) was carried out on Multichrom B (Beckmann, Munich). In hepatic coma high concentrations of Met, Tyr, Ala, Lys and Arg are found. The deviations of PAA from normal controls show between acute and chronic hepatic failure no qualitative but only quantitative differences. In diabetic coma the three branches chain AA (Val, Leu and Ile) were elevated upon 3--5 times of normal. Near normal concentrations are found for the AA Thr, Ser, Gly, Ala, Met and the aromatic AA (Phe and Tyr). The quotient between the branched chain and aromatic AA lies for hepatic coma at a mean of 1.18 and by diabetic coma at 7.18 (p less than 0.001). In hepatic coma a correlation exists between the level of the AA-quotient improvement and the decrease with a deterioriation of the metabolic encephalopathy. The high level of the AA-quotient in the patients of diabetic "coma" gives therefore a good explanation for the rare unconscious state of these patients.
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PMID:[Differences in plasma aminograms in hepatic and diabetic coma]. 74 45

The molecular lesions in two patients exhibiting classical clinical manifestations of MELAS (mitochondrial encephalopathy, lactic acidosis, and strokelike episodes) syndrome have been investigated. A recently reported disease-related A----G base substitution at nt 3243 of the mtDNA, in the DHU loop of tRNA(Leu), was detected by restriction-enzyme analysis of the relevant PCR-amplified segment of the mtDNA of one patient but was not observed, by either restriction-enzyme analysis or nucleotide sequencing, in the other. To define the molecular lesion in the patient who does not have the A----G base substitution at nt 3243, the total mitochondrial genome of the patient has been sequenced. An A----G base substitution at nt 11084, leading to a Thr-to-Ala amino acid replacement in the ND4 subunit of the respiratory complex I, is suggested to be a disease-related mutation.
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PMID:A new disease-related mutation for mitochondrial encephalopathy lactic acidosis and strokelike episodes (MELAS) syndrome affects the ND4 subunit of the respiratory complex I. 821 27

The pathogenesis of brain edema in acute liver failure is poorly understood. We have previously shown that rats with ischemic acute liver failure (portacaval anastomosis followed by hepatic artery ligation) exhibit brain edema and intracranial hypertension, with swelling of cortical astrocytes as the most prominent neuropathological abnormality. Because ammonia has been shown to induce swelling of astrocytes in vivo and in vitro, we examined the relationship between brain ammonia, amino acids generated from ammonia metabolism and brain water content in this model. Four groups of animals were studied: rats subjected to two sham operations, rats subjected to portacaval anastomosis and a sham operation, rats subjected to a sham operation and hepatic artery ligation and rats subjected to portacaval anastomosis and hepatic artery ligation. The last group of animals was studied at three progressive stages of encephalopathy. Cortical gray matter water increased from 80.26% +/- 0.22% (sham + sham) to 82.46% +/- 0.06% (last stage of devascularization). In cerebral cortex, brain ammonia increased to a maximum of 5.4 mmol/L. Glutamine, generated in glial cells from ammonia and glutamate, increased sixfold to 24 mmol/L and remained at this level throughout all stages of encephalopathy. Alanine, which may be generated from the transamination of glutamine, increased in parallel to the increase in water (r = 0.80, n = 15). In this model of fulminant liver failure and associated brain edema, brain ammonia increases to levels associated with in vitro swelling of brain slices and glial cells. The accumulation of osmogenic aminoacids such as glutamine and alanine may contribute to the selective astrocyte swelling seen in this condition.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ammonia and related amino acids in the pathogenesis of brain edema in acute ischemic liver failure in rats. 154 26

Using an indwelling cisterna magna catheter technique, serial CSF samples were analyzed for amino acid content in rats at various stages of portal-systemic encephalopathy resulting from ammonium acetate administration following portacaval anastomosis. Anastomosis alone resulted in increased CSF concentrations of glutamine, tyrosine, phenylalanine, glutamate and alanine. GABA levels, on the other hand were not significantly changed. Onset of severe neurological symptoms following ammonium acetate administration resulted in selectively increased CSF alanine. Other amino acids were not further increased at severe stages of encephalopathy. Increased CSF alanine probably results from increased glutamine transamination in the brains of portacaval shunted rats.
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PMID:Cerebrospinal fluid amino acids in relation to neurological status in experimental portal-systemic encephalopathy. 174 65

The total sequences of mitochondrial DNA were determined in two patients with juvenile-onset mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) due to Complex I deficiency. Patients 1 and 2 had three and two unique point mutations, respectively, causing replacement of phylogenically conserved amino acids. A transition from G to A was found at nucleotide position 5601 in the alanine tRNA gene of Patient 2, and a transition from A to G was found at 3243 in the leucine (UUR) tRNA gene of both patients. The latter mutation located at the phylogenically conserved 5' end of the dihydrouridine loop of the tRNA molecule, and was present in two patients with adult-onset MELAS and absent in controls. These results indicate that a mass of mtDNA mutations including the A-to-G transition in the tRNA(Leu) gene is a genetic cause of MELAS.
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PMID:Mitochondrial DNA mutations in mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). 189 74

Pyrithiamine-induced thiamine-deficiency encephalopathy in the rat shows many neuropathological and biochemical similarities to Wernicke's encephalopathy in humans. Treatment of rats with pyrithiamine resulted in moderate reductions of glutamate in thalamus and pons and in generalized severe reductions of aspartate in pons (by 89%, p less than 0.01), thalamus (by 83%, p less than 0.01), cerebellum (by 53%, p less than 0.01), and cerebral cortex (by 33%, p less than 0.05). Alanine concentrations were concomitantly increased. Activities of the thiamine-dependent enzyme alpha-ketoglutarate dehydrogenase (alpha KGDH) were decreased in parallel with the aspartate decreases; pyruvate dehydrogenase complex activities were unchanged in all brain regions. Following thiamine administration to symptomatic pyrithiamine-treated rats, neurological symptoms were reversed and concentrations of glutamate, aspartate, and alanine, as well as alpha KGDH activities, were restored to normal in cerebral cortex and pons. Aspartate levels and alpha KGDH activities remained below normal values, however, in thalamus. Thus, pyrithiamine treatment leads to reductions of cerebral alpha KGDH and (1) decreased glucose (pyruvate) oxidation resulting in accumulation of alanine and (2) decreased brain content of glutamate and aspartate. Such changes may be of key significance in the pathophysiology of the reversible and irreversible signs of Wernicke's encephalopathy in humans.
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PMID:Effect of pyrithiamine treatment and subsequent thiamine rehabilitation on regional cerebral amino acids and thiamine-dependent enzymes. 256 21


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