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

Reye's syndrome (RS) has been defined by the CDC as an acute non-inflammatory encephalopathy and hepatopathy, with no reasonable explanation for the cerebral and hepatic abnormalities. The diagnosis of RS is made by a constellation of clinical and laboratory features, none of which are pathognomonic. The demonstration of a fatty infiltration on liver biopsy is not really specific. On the other hand, the mitochondrial ultrastructural abnormalities appear to be characteristic of RS. Cerebral edema with intracranial hypertension represents the most immediate threat to life, the cause of the encephalopathy being unknown. The treatment of RS consists in perfusion of hypertonic glucose solution and management of intracranial hypertension. Grade I RS should be recognized early and treated with intravenous glucose. A number of metabolic disorders may yield a clinical picture resembling RS. These include disturbances of organic acid metabolism, urea cycle defects, and disorders of carbohydrate metabolism. The pathogenesis of RS is a mitochondrial insult induced by different viruses, drugs, exogenous toxins, and genetic factors. In the USA, pilot studies showed that a majority of RS cases may be attributable to salicylate use. In France, RS remains unfrequent although no precise epidemiological data are available. An epidemiological study appears therefore necessary for a better understanding of this mysterious syndrome. There is a need for a biological marker of the mitochondrial injury.
 ...
PMID:[Reye's syndrome. A current entity which remains enigmatic]. 305 99

Concerned by mortality due to recurrent bleeding and associated risk factors in cirrhotic patients, we attempted to compare the efficiency of perivascular sclerotherapy using quinine urea with that of intravascular polidocanol and to determine the predictive factors of clinical outcome. Of 74 patients admitted for bleeding esophageal varices, 31 were treated with perivascular sclerotherapy (group I), and 43 with intravascular sclerotherapy (group II). Three months later, only 63 p. 100 of patients in group I had not rebled, compared to 90 p. 100 of patients in group II (p less than 0.001). After 6 months, no significative difference was found between the two groups. The one year survival rate was 44 p. 100 in group I and 79 p. 100 in group II (p less than 0.002). Encephalopathy and ascites were found to be predictive factors of mortality, whereas neither clinical or biologic factors were found to be predictive for recurrent bleeding. These results suggest that in esophageal sclerotherapy, the intravascular route with polidocanol provides earlier results and a better one year survival rate, compared with the perivascular route. However, survival rates depend on encephalopathy and ascites criteria.
 ...
PMID:[Comparative efficacy of endoscopic sclerosis of esophageal varices by intravariceal injection of polidocanol and perivariceal injection of quinine-urea]. 306 43

A seventy-two-year-old man with hypertensive cerebral hemorrhage acutely developed severe headache, nausea, vomiting, agitation, and disorientation with abrupt rise in blood pressure on the sixth day after the onset. At that time, there were no remarkable changes in focal neurologic deficits, and repeated brain CT scans revealed a small hematoma located in the right basal ganglia without further enlargement or herniation. Blood chemistry and arterial gas analysis were within the normal ranges except for a slight rise in blood urea nitrogen. Similar episodes occurred three times within two days, and each time the cerebral symptoms disappeared in accordance with lowering of blood pressure by antihypertensive therapy. Complication of hypertensive encephalopathy was strongly suggested. The authors discuss the pathophysiology of this encephalopathy in relation to cerebral hemorrhage.
 ...
PMID:Transient encephalopathy related to rapidly and markedly elevated blood pressure in acute stage of hypertensive cerebral hemorrhage--relationship to hypertensive encephalopathy--a case report. 317 64

Ultrastructural findings in the brains and livers of four calves affected with citrullinaemia due to a hereditary deficiency of the urea cycle enzyme arginosuccinate synthetase are described. The calves were affected in the 1st week of life with severe neurological disease characterised by depression, head pressing, stupor, convulsions and coma, accompanied by marked elevation of plasma citrulline and increasing plasma ammonia levels. Lesions included mild to moderate diffuse astroglial oedema in the cerebrocortical grey matter, and mild to severe hepatocellular hydropic change. The onset of the severe neurological signs was correlated with increasing levels of plasma ammonia, and the cerebral lesions were considered consistent with a bovine hyperammonaemic encephalopathy.
 ...
PMID:Ultrastructural findings in citrullinaemia in Holstein-Friesian calves. 321 35

In view of the putative involvement of calcium in uremic encephalopathy and the critical importance of this element in juvenile development, we examined the effect of temporary restriction of dietary calcium intake on serum chemistry and the quantitative electroencephalogram (Q.EEG) in unilaterally 3/4 nephrectomized juvenile male Sprague-Dawley rats. Animals were renally infarcted at 22-26 days of age (50-74 g) and placed on one of two isocaloric dietary regimens: powdered normal rat diet (ND, n = 25) or low calcium diet (LCD, n = 8) for 30 days. At this time, ND animals showed normal serum chemistries, whereas LCD rats were hypocalcemic and azotemic with significantly elevated blood urea nitrogen (BUN) and serum creatinine concentrations and reduced renal creatinine clearance values. All animals thereafter received ND for 25-34 further days, during which time chronic Q.EEG electrodes were implanted. At the end of the common ND feeding period, serum chemistry values were equal and normal in both groups. The average theta/alpha ratio (TAR) of the overnight Q.EEG was assessed for 3 days. We found that the TAR of previously LCD animals was significantly elevated compared with ND rats. This indicates an encephalopathic slowing of the background rhythm of these animals. We conclude that, following restoration of a transient uremic and hypocalcemic episode induced by LCD feeding, the Q.EEG background frequency of juvenile renally impaired rats was abnormally slow after 30 days of ND feeding.
 ...
PMID:Juvenile hypocalcemia provokes persistent electroencephalographic change in renally compromised rats. 323 Feb 33

There is substantial clinical and experimental evidence to suggest that ammonia toxicity is a major factor in the pathogenesis of hepatic encephalopathy associated with subacute and chronic liver disease. Ammonia levels in patients with severe liver disease are frequently found to be elevated both in blood and cerebrospinal fluid (csf). Hepatic encephalopathy results in neuropathological damage of a similar nature (Alzheimer type II astrocytosis) to that found in patients with congenital hyperammonemia resulting from inherited defects of urea cycle enzymes. Following portocaval anastomosis in the rat, blood ammonia concentration is increased 2-fold, and brain ammonia is found to be increased 2-3-fold. Administration of ammonia salts or resins to rats with a portocaval anastomosis results in coma and in Alzheimer type II astrocytosis. Since the CNS is devoid of effective urea cycle activity, ammonia removal by brain relies on glutamine formation. Cerebrospinal fluid and brain glutamine are found to be significantly elevated in cirrhotic patients with encephalopathy and in rats following portocaval anastomosis. In both cases, glutamine is found to be elevated in a region-dependent manner. Several mechanisms have been proposed to explain the neurotoxic action of ammonia. Such mechanisms include: Modification of blood-brain barrier transport; alterations of cerebral energy metabolism; direct actions on the neuronal membrane; and decreased synthesis of releasable glutamate, resulting in impaired glutamatergic neurotransmission.
 ...
PMID:Ammonia: key factor in the pathogenesis of hepatic encephalopathy. 330 79

In patients with portal hypertension and tense ascites, large-volume paracentesis improves patient comfort and may improve systemic hemodynamics. However, it has been avoided in nonedematous patients because of concern for complications, including intravascular volume depletion. In this study, 12 nonedematous patients with chronic liver disease, portal hypertension and tense ascites underwent 14 large-volume (5-liter) paracenteses for the relief of discomfort and/or respiratory distress. Plasma volume was measured directly by a dilution method with 125I-labeled human serum albumin prior to and at 24 or 48 hr after 13 of the paracenteses. All patients felt better postparacentesis. No dizziness, hypotension, tachycardia, encephalopathy or change in mean serum sodium, creatinine or blood urea nitrogen occurred. Two patients experienced a decrease in hematocrit, which was not explained by blood loss or increase in plasma volume. Mean plasma volume was 3,713 +/- 129 ml (55.1 +/- 1.5 ml per kg ideal body weight) preparacentesis and 3,684 +/- 136 ml postparacentesis, the difference being -0.78% (p = 0.48, NS). Our results suggest that 5-liter paracentesis in nonedematous patients with tense portal hypertension-related ascites improves patient comfort and is not associated with a decrease in measured plasma volume.
 ...
PMID:Large-volume paracentesis in nonedematous patients with tense ascites: its effect on intravascular volume. 335

It has recently been shown that repeated large-volume paracentesis associated with intravenous albumin infusion is a rapid, effective, and safe therapy of ascites in cirrhosis. To investigate whether intravenous albumin infusion is necessary in the treatment of cirrhotics with large-volume paracentesis, 105 patients with tense ascites were randomly allocated into two groups. Fifty-two patients (group 1) were treated with paracentesis (4-6 L/day until disappearance of ascites) plus intravenous albumin infusion (40 g after each tap), and 53 (group 2) with paracentesis without albumin infusion. After disappearance of ascites, patients were discharged from the hospital with diuretics. Patients developing tense ascites during follow-up were treated according to their initial schedule. Paracentesis was effective in eliminating the ascites in 50 patients from group 1 and in 48 from group 2, with the duration of the hospital stay being approximately 11 days in both groups. Paracentesis plus intravenous albumin did not induce significant changes in standard renal function tests, plasma renin activity, and plasma aldosterone. In contrast, paracentesis without albumin was associated with a significant increase in blood urea nitrogen, a marked elevation in plasma renin activity and plasma aldosterone concentration, and a significant reduction in serum sodium concentration. One patient from group 1 and 11 from group 2 developed renal impairment or severe hyponatremia after treatment, or both (chi 2 = 9.19; p less than 0.01). The development of these complications could not be predicted by clinical and laboratory data before treatment. Although the probability of survival after entry into the study was similar in patients from both groups, a multivariate analysis identified the development of hyponatremia or renal impairment, or both, following the first paracentesis treatment and the occurrence of other complications during the first hospitalization (encephalopathy, gastrointestinal bleeding, and severe infection) as being the only independent predictors of mortality. These results indicate that intravenous albumin infusion is important in avoiding renal and electrolyte complications and activation of endogenous vasoactive systems in cirrhotics with ascites who are treated with repeated large-volume paracentesis. The development of such complications may impair survival in these patients.
 ...
PMID:Randomized comparative study of therapeutic paracentesis with and without intravenous albumin in cirrhosis. 336 Feb 70

Portocaval anastomosis (PCA) in the rat leads, within 4 weeks, to severe liver atrophy, sustained hyperammonemia, and increased brain ammonia. Because brain is not equipped with an effective urea cycle, removal of ammonia involves glutamine synthesis and PCA results in significantly increased brain glutamine. Glutamine synthetase activities, however, are decreased by 15% in cerebral cortex and are unchanged in brainstem of shunted rats. Administration of ammonium acetate to rats following PCA results in severe encephalopathy (loss of righting reflex and, ultimately, coma). Glutamine concentrations in brainstem of comatose rats are increased a further two-fold, whereas those of cerebral cortex are unchanged. Consequently, ammonia levels in cerebral cortex reach disproportionately high levels (of the order of 5 mM). These findings suggest a limitation in the capacity of cerebral cortex to remove additional blood-borne ammonia by glutamine formation following PCA. Such mechanisms may explain the hypersensitivity of rats with PCA and of patients with portal-systemic shunting to small increases of blood ammonia. Disproportionately high levels of brain ammonia in certain regions, such as cerebral cortex, may then result in alterations of inhibitory neurotransmission and, ultimately, loss of cellular (astrocytic) integrity.
 ...
PMID:Regional differences in the capacity for ammonia removal by brain following portocaval anastomosis. 339 40

Sparse-fur mice which are deficient in ornithine transcarbamylase, the second-step enzyme in the urea cycle, were examined for hyperammonemia and its relationship with encephalopathy. We compared amino acid concentrations in the serum and brain of spf mice with those of control mice. Unlike hepatic encephalopathy we could not find marked amino acid changes in the serum of spf mice besides low levels of citrulline and arginine. But in the brain of spf mice, glutamine was increased strikingly during hyperammonemia, and a concomitant accumulation of large neutral amino acids such as tyrosine, phenylalanine, methionine, and histidine was observed. The accumulation of these large neutral amino acids in the brain was not influenced by 24-hr fasting which caused increases in branched chain amino acids in the serum. From these results, we conclude that the accumulation of the large neutral amino acid in the brain of hyperammonemic state is caused by uptake of ammonia in the brain and the subsequent accumulation of glutamine, but is not influenced by a decreased ratio of branched chain amino acids to aromatic amino acids in the serum.
 ...
PMID:Accumulation of large neutral amino acids in the brain of sparse-fur mice at hyperammonemic state. 343 85


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>