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PubMed1989

Effects of ammonium chloride, salicylate, and carnitine on palmitic acid oxidation in rat liver slices.

To explore the possible association of hyperlipidemia with hyperammonemia and aspirin ingestion, the effects of NH4+, salicylate, and carnitine on the oxidation of [1-14C]palmitic acid to acid-soluble products (ASP) and to CO2 were investigated in rat liver slices. DL-carnitine (5 mM) increased total oxidation (ASP + CO2) more than oxidation to CO2. KCN (1.5 mM) inhibited more than 90% of the oxidation. NH4Cl inhibited the oxidation that reached a maximum at about 40 mM, but the inhibition of oxidation to CO2 (63%) was larger than that of total oxidation (30%). Carnitine did not influence NH4+ inhibition, which is consistent with the results reported for isolated mitochondria. Salicylate effects depended on salicylate concentration as well as on the presence of carnitine. In the absence of carnitine, inhibition of total oxidation reached 90% at 3 mM salicylate but that of oxidation to CO2 reached 50%. Velocity calculated at saturating palmitic acid concentration for total oxidation was slightly increased by 0.75 mM salicylate, but the increase for oxidation to CO2 was larger. At 3 mM salicylate, velocity at saturating palmitic acid concentration for the oxidation was decreased, but the decrease for oxidation to CO2 was smaller than for total oxidation. Carnitine partially relieved the inhibition of total oxidation and further increased the formation of CO2. The combination of 20 mM NH4Cl and 0.75 mM salicylate inhibited total oxidation, which was more than additive of the individual effects, and carnitine partially relieved the inhibition. It is concluded that NH4+ exerted a stronger inhibition of oxidation to CO2 than of oxidation to ASP, whereas salicylate strongly inhibited the oxidation to ASP but increased the oxidation to CO2 by uncoupling mitochondrial oxidative phosphorylation. Therefore, hyperammonemia and aspirin ingestion can inhibit fatty acid oxidation and mitochondrial metabolism that could lead to the pathophysiology seen in some childhood diseases such as Reye's syndrome. Carnitine therapy might offer some benefits.

Ammonium Chloride↗

PubMed1994

[Brain monoamines and behavior in hyperammonemic sparse-fur mice].

Hyperammonemia due to inherited deficiency of enzymes in the liver is also found in sparse-fur (spf) mice, which have OTC (ornithine transcarbamylase) deficiency, a high concentration of ammonia in the blood and a high concentration of glutamine and tryptophan after weaning. Abnormal behavior was observed during the hyperammonemic period in spf mice. Autonomic locomotor activity in spf mice during this period was enhanced under light but suppressed in the dark. The circadian rhythm of autonomic locomotor activity disappeared from 3 to 5 weeks and reappeared at 8 weeks. The frequency of the head twitch response induced by 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) decreased in the hyperammonemic period, in which the concentration of brain tryptophan (Trp) and 5-hydroxyindoleacetic acid (5-HIAA) increased, the ratio of 5-HIAA to serotonin (5-HT) in the brain increased and [3H]-ketanserin binding to 5-HT2 receptor significantly decreased in the frontal cortex and whole brain. Down regulation in the postsynaptic 5-HT2 receptor may have provoked the inhibition of 5-MeODMT-induced head twitch response. The abnormal behavior of spf mice may derive from increased tryptophan in the brain due to hyperammonemia, increased 5-HT turnover rate and down regulation in the postsynaptic 5-HT2 receptor.

Amino Acid Metabolism, Inborn Errors↗

PubMed2006

Gastric adenocarcinoma in a horse with portal vein metastasis and thrombosis: a novel cause of hepatic encephalopathy.

A 17-year-old Quarter horse mare was referred to Cornell University for postmortem examination after 72 hours of encephalopathy that consisted of depression, mania, and blindness. A plasma sample and cerebral spinal fluid demonstrated hyperammonemia. Gross necropsy examination findings included the following: mild icterus, a transmural mass in the glandular portion of the gastric fundus, multiple masses throughout the liver, and a large tumor thrombus in the portal vein. Microscopically, the gastric mass, hepatic masses, and portal vein thrombus were composed of similar neoplastic epithelial cells that formed variably sized acini and branching cords separated by a dense desmoplastic stroma. Throughout the cerebral frontal cortex were numerous Alzheimer type II astrocytes. Hepatic encephalopathy was caused by gastric adenocarcinoma, with metastasis to the liver and the portal vein. The clinical and pathologic lesions from this unique case, as well as hyperammonemia and portal vein thrombosis in the pathogenesis of hepatic encephalopathy, are discussed.

Adenocarcinoma↗

PubMed1993

Reduction of increased signal intensity in the basal ganglia on T1-weighted MR images during treatment of hepatic encephalopathy.

A 61-year-old man with liver cirrhosis showed a symmetrical increase in the signal intensity of the basal ganglia on T1-weighted magnetic resonance (MR) images, which was diminished after 3 months of treatment for hepatic encephalopathy. He recovered from encephalopathy with treatment, and liver dysfunction (hyperammonemia and abnormal blood coagulation) as well as the results of quantitative psychometric tests showed a marked improvement. The cause of these high signal intensity changes on T1-weighted images and the reason for their partial reversibility are not known, but hyperammonemia due to portal-systemic shunting might be closely related to these clinical observations.

Ammonia↗

PubMed1993

Portal-systemic encephalopathy and hypothalamic hypothyroidism: effect of thyroid hormone on ammonia metabolism.

We describe a 53-year-old woman with portal-systemic encephalopathy and altered thyroid function. Endocrinological studies revealed low levels of free thyroid hormone with an inappropriately low level of thyroid-stimulating hormone that responded to bolus injection of thyrotropin-releasing hormone with a normal but somewhat delayed pattern. On the diagnosis of hypothalamic hypothyroidism, she was treated with levothyroxine sodium. Thyroid hormone replacement improved not only the symptoms of hypothyroidism but the hyperammonemia and consciousness disturbance, which suggested a hitherto undescribed possibility that hypothyroidism may be an exacerbation factor of hyperammonemia and portal-systemic encephalopathy.

Ammonia↗

PubMed1997

Adult-onset type II citrullinemia: clinical pictures before and after liver transplantation.

In a 25-year-old man with adult-onset type II citrullinemia, liver transplantation resulted in elimination of hyperammonemia and amino acid abnormalities associated with the disease. Postoperatively, a high intensity area in the right cingulate gyrus on a T2-weighted brain magnetic resonance imaging (MRI) also disappeared, suggesting that it reflected an early reversible lesion due to the hyperammonemia. Moreover, the serum level of pancreatic secretory trypsin inhibitor (PSTI), which had been elevated, was normalized. Since the levels of PSTI mRNA and PSTI have been reported to be increased in the livers of type II citrullinemia patients, measurement of serum PSTI levels could aid in the diagnosis of this disease.

Adult↗

PubMed1990

Subclinical ammonia toxicity in steers: effects on hepatic and portal-drained visceral flux of metabolites and regulatory hormones.

Four calves (avg wt 161 kg) were surgically fitted with indwelling catheters in the femoral artery and femoral, portal, hepatic and mesenteric veins to study the effects of subclinical ammonia toxicity on portal-drained viscera (PDV) and hepatic (HEP) net flux of key metabolites and pancreatic hormones. Hyperammonemia was induced via administration of ammonium chloride (NH4Cl; 12 mumol.kg BW-1.min-1) via the femoral vein catheter for 240 min; infusions were preceded (PRE) and followed (POST) by 60- and 180-min control periods, respectively. Blood samples were obtained from the arterial catheters, and portal and hepatic vein catheters. Net flux rates were calculated by multiplying venoarterial differences by blood flow. Arterial plasma ammonia N peaked (P less than .01) at 327 micrograms/dl; hepatic ammonia extraction increased (P less than .01) from 10 to 23% during NH4Cl infusion. Arterial plasma glucose concentrations increased (P less than .05) during NH4Cl infusion (90.5 vs 82.6 mg/dl) concomitant with trends toward a reduction in net HEP glucose output. Portal-drained visceral release of insulin did not increase (P greater than .10) during NH4Cl infusion despite the steady rise in circulating glucose concentration; however, cessation of NH4Cl infusion resulted in a 109% increase (P less than .05) in PDV insulin release at +60 min POST. Plasma L-lactate, nonesterified fatty acids, urea N and glucagon concentrations and net fluxes were variable throughout the experiment. Results tend to indicate that hyperammonemia reduced hepatic glucose output and glucose-mediated pancreatic insulin release.

Ammonia↗

PubMed1998

Influence of intravenous L-carnitine administration in sheep preceding an oral urea drench.

Two experiments were conducted to investigate the effect of i.v. administration of L-carnitine on selected metabolites in sheep and to determine the feasibility of using L-carnitine to ameliorate the deleterious effects of hyperammonemia in sheep. In Exp. 1, i.v. L-carnitine solutions were administered at three levels in a replicated Latin square: 0 (CONT), 6.36 (CAR 1), and 12.72 (CAR 2) mmol L-carnitine/kg x (75) BW using Suffolk ewes (n = 6; average BW 75+/-3 kg). Plasma L-carnitine concentration was increased (P<.05) by treatment (51.9 vs 102.3, and 96.4 micromol/L in CONT, CAR 1, and CAR 2, respectively). Plasma glucose concentration was elevated (P<.05) in CAR 2 and CAR 1. Plasma NEFA concentration was highest (P<.05) in CAR 2. Area under the response curve for glucose was greater (P<.02) in CAR 2. In Exp. 2, Suffolk ewes (n = 16; average BW 48+/-2 kg) were used in a randomized complete block design with a 2x2 factorial treatment arrangement to determine the effects of i.v. L-carnitine administration during an oral urea load test (OULT). L-Carnitine (0 and 6.36 mmol/kg x (75) BW) was administered i.v. at 30 min, and an oral urea drench (50% wt/vol; 0 and 300 mg/kg BW) was administered at 60 min. Plasma L-carnitine was increased (P<.0001) by i.v. L-carnitine. Plasma ammonia N was highest (P<.0001) in the UREA treatment compared with the CONT, CARN, and CARN + UREA treatments (148 vs 95, 101, and 108 micromol/L, respectively). Intravenous L-carnitine administration influenced plasma glucose and NEFA concentrations in sheep and, when administered 30 min preceding an OULT, prevented the development of subclinical hyperammonemia in sheep.

Administration, Oral↗

PubMed1990

A case of ornithine transcarbamylase deficiency with acute and late onset simulating Reye's syndrome in an adult male.

A 15-year-old male was admitted to the hospital because of a disturbance of consciousness. He was in good mental and physical condition until the previous day, when he vomited and experienced a reduction of consciousness. He was brought to the hospital the day following the onset of symptoms. On admission the patient was stuporous. Neurological focal signs were not demonstrated. Computed tomographic (CT) scanning on admission showed no definite abnormality. Cerebrosprinal fluid had no pleocytosis. At this time, Reye's syndrome was suspected because of the acute change of consciousness and the presence of hyperammonemia. The disturbance of consciousness progressed and he became comatose on the day following admission. CT scanning showed that the suprasellar, ambient and quadrigeminal cisterns could almost not be detected and the bilateral ventricles were narrowed. The plasma aminogram demonstrated an elevation of alanine, lysine, glutamine, glutamic acid, aspartate and proline. Ketonuria was negative, but the urinary excretion of orotic acid was markedly increased. This data was indicative of the existence of an ornithine transcarbamylase (OTC) deficiency. The patient was died on the third day after hospitalization. The OTC activity in the liver was 10% of normal. Activities of other enzymes in the urea cycle were within normal limits. It is unusual that the symptoms of the enzyme deficiency occurred, both acutely and late at an adult age, as in this case. This case demonstrates that OTC deficiency should be considered in the differential diagnosis of hyperammonemia of adult onset.

Adolescent↗

PubMed1999

[Carnitine as a vitamin-like biofactor].

Carnitine is a well-known cofactor for the beta-oxidation of long-chain fatty acid. It also plays a role in transport of acetyl moity for fatty acid and cholesterol synthesis, excretion of organic acid and xenobiotic acid as carnitine ester, and control of ratio of acetylCoA to CoA. Therapeutic effect of acetylcarnitine on Alzheimer disease and HIV-infection, and aberrant incorporation acetylcarnitine into brain under chronic fatigue syndrome have been reported. Carnitine deficiency causes hyperammonemia through suppression of gene expression of urea cycle enzymes. On the other hand, a large amount of carnitine has a therapeutic effect on hyperammonemia by still unclear mechanism. These suggest carnitine as a multifunctional biofactor.

Animals↗

PubMed2000

[Empyema thoracis accompanied by hyperammonemic encephalopathy].

A 50-year-old man was admitted to our hospital due to consciousness disturbance. On admission, he was comatose (200 on the Japan Coma Scale) but brain computed tomographic (CT) scans were normal. Chest radiographs and CT scans on admission revealed massive pleural effusion in the right hemithorax. A culture of purulent pleural fluid yielded three species of anaerobes, including Bacteroides fragilis. Laboratory examinations revealed markedly elevated WBC count, CRP, and serum ammonia (586 micrograms/dl). However, liver function was almost normal and no other metabolic disorders were demonstrated. After the initiation of antibiotic therapy and pleural drainage, the patient's cousciousness level gradually improved in parallel with decreasing serum levels of ammonia and CRP. Because no other potential causes of hyperammonemia were observed, we concluded that the consciousness disturbance was due to hyperammonemia presumably caused by a urease-producing anaerobe infecting the right pleural space.

Ammonia↗

PubMed2000

[A case of portal-systemic encephalopathy associated with Sheehan's syndrome].

A 66-year-old woman had had recurrent episodes of disturbed consciousness whenever she had been constipated or dehydrated. She had been inactive and afflicted with obstinate constipation since she had menopause at age of 32. She underwent gastrectomy for gastric ulcer at age of 37. Laboratory examination showed marked hyperammonemia, reduction in Fisher ratio, and poor excretion of ICG. Furthermore, hypopituitarism and secondary hypothyroidism were found. She was diagnosed as Sheehan's syndrome. A T1-weighted MRI demonstrated symmetrical high intensity in the bilateral globus pallidus and empty sella. The histological examination of the liver revealed a mild lymphocytic infiltration without liver cirrhosis. Abdominal angiography showed a large shunt vessel between the splenic vein and the left renal vein. After embolization of the shunt vessel, hyperammonemia and neurological impairment improved. Additionally multiple hormones replacement has been useful to reduce the drugs of standard therapy for hepatic coma. In this case, we speculated that Sheehan's syndrome accelerated the constipation and worsened the shunt encephalopathy.

Aged↗

PubMedDate not supplied

Comparison of the long-term results of distal splenorenal shunt and esophageal transection for the treatment of esophageal varices.

BACKGROUND/AIMS: This study was undertaken to evaluate the comparison of long-term results of distal splenorenal shunt and esophageal transection for the treatment of esophageal varices. METHODOLOGY: Twenty-four cirrhotic patients underwent distal splenorenal shunt, and 19 cirrhotic patients underwent esophageal transection with complete variceal eradication and follow-up for at least 3 years. RESULTS: No recurrent varix was observed in the distal splenorenal shunt group. The cumulative recurrence rates of varices in the esophageal transection group were 31.6%, and 52.5% at 5 and 10 years, respectively. The cumulative rates of hyperammonemia at 5 and 10 years were significantly higher in the distal splenorenal shunt group (30.4%, 30.4%) than in the esophageal transection group (0%, 5.6%) (P = 0.009). The cumulative survival rates in the distal splenorenal shunt group versus the esophageal transection group were 90.9% versus 94.7%, and 85.2% versus 81.7% at 5 and 10 years (NS). CONCLUSIONS: These results suggest that distal splenorenal shunt is more effective than esophageal transection in preventing recurrence of esophageal varices, but is associated with a higher incidence of hyperammonemia.

Esophageal and Gastric Varices↗

PubMed2001

[Molecular genetic studies of mitochondrial ornithine transporter deficiency (HHH syndrome)].

Mitochondrial ornithine transporter deficiency has been called HHH syndrome, because this disorder is characterized by three biochemical abnormalities; hyperornithinemia, hyperammonemia, and homocitrullinuria, and presents with various neurological symptoms; mental retardation, spastic paraparesis with pyramidal signs, cerebellar ataxia and episodic disturbance of consciousness or coma due to hyperammonemia. We identified four mutations in the mitochondrial ornithine transporter gene (ORNT1) of Japanese patients with HHH syndrome. These include a nonsense mutation (R179X), associated with exon skipping, missense mutations (G27E, P126R), and an insertion of AAC between codons 228 and 229, leading to an insertion of amino acid Asn. Especially, R179X was detected 4 of 7 Japanese patients (8 of 14 alleles), implying that this is a common mutation in Japanese population.

Amino Acid Transport Systems, Basic↗

PubMedDate not supplied

Neonatal onset propionic acidemia without acidosis: a case report.

Propionic acidemia is an inherited disorder of organic acid metabolism characterized by a spectrum of clinical and biochemical findings. The usual presentation is life-threatening ketoacidosis and hyperammonemia. In this report we present a neonate with propionic acidemia presenting with prominent neurologic problems without ketoacidosis. The patient had a serum ammonia level of 3,500 microg/dl which was effectively lowered to normal values in 48 hours by peritoneal dialysis, with remarkable improvement in neurologic status. However, she developed Candida albicans peritonitis, and sepsis and died of cardiorespiratory failure. Infants who have an early onset propionic acidemia have a high mortality and morbidity rate. In conclusion, propionic acidemia should be in the differential diagnosis of patients with neurologic symptoms and hyperammonemia with or without acidosis.

Ammonia↗

PubMed1992

Plasma ammonia in patients with acute leukemia.

Plasma ammonia level (PAL) was studied in 43 cases of acute leukemia (AL). PAL was 39.21 +/- 26.2 mumol/L in normal controls and 38.8 +/- 16.6 mumol/L in leukemic patients before chemotherapy. High PAL was found in 40 cases after chemotherapy. Six cases showed clinical manifestations due to severe hyperammonemia, including dizziness, lethargy, confusion, coma and mental changes of various degree, and there was also respiratory alkalosis. After ammonia-trapping therapy, 4 of the 5 patients recovered. The authors believe that high PAL is not uncommon after chemotherapy in leukemic patients. Respiratory alkalosis and unexplained mental and neurologic changes following intensive chemotherapy are useful clues for the diagnosis of hyperammonemia syndrome. Early diagnosis and treatment with ammonia-trapping may improve the rates of remission and survival.

Adolescent↗

PubMed1992

[A case of citrullinemia associated with isolated ACTH deficiency, rapidly developing coma].

We report a 41-year-old male of citrullinemia associated with argininosuccinate acid synthetase deficiency. He was admitted to the Hitachi General Hospital because of finger tremor, restlessness and urinary incontinence. He had short stature and a poor appetite. Laboratory evaluation was summarized as follows: mild hypoglycemia, low plasma cortisol levels, delayed response of 17-OHCS and 17-KS to ACTH administration in urine, and delayed response of plasma ACTH level to insulin administration. In this case, ACTH deficiency is estimated to be a dysfunction of the hypothalamus. Replacement therapy of hydrocortisone improved his symptoms. He was readmitted to the hospital because of delirium and confusion, two weeks after the hydrocortisone administration. At that time, he had flapping tremor. Laboratory examination revealed hyperammonemia (NH3: 231 micrograms/dl) and mild elevation of GOT and GPT. Serum and urinary amino acid determination showed marked elevation of citrulline (478.1 nmol/ml in serum, 4681.2 mumol/day in urine). Lactulose administration, low protein diet and plasmapheresis were started, but he went into a coma. Without any improvement, he died on the 29th hospital day. Autopsy examination of the liver disclosed fatty change. Adrenal cortex depicted severe atrophy. Biochemical analysis of urea cycle enzymes of the liver and kidney showed decreased activity of argininosuccinate synthetase (liver: 0.0022 U/mg protein, 5% of that normal liver, kidney: 0.003 IU/mg protein, 20% of that in normal kidney). Citrullinemia associated with ACTH deficiency have not reported in the literature. It may be presumed that ACTH deficiency is concerned with the delayed onset of hyperammonemia. The relation between citrullinemia and endocrinological abnormalities is also discussed.

Adrenal Cortex↗

PubMed2004

Inhibitory effects of Cimicifuga heracleifolia extract on glutamate formation and glutamate dehydrogenase activity in cultured islets.

Hyperinsulinism-hyperammonemia syndrome is due either to hyperactivity of GDH or impaired inhibition of GDH by GTP. We have investigated the effect of Cimicifuga heracleifolia extract on the activities of glutamate dehydrogenase (GDH) in cultured rat islets. When the extract was present in the culture medium for 24 h prior to cell harvest, the Vmax of GDH was decreased by 45% with no significant change in Km. In addition, the concentration of alpha-ketoglutarate increased by approximately 39%, and glutamate decreased by 48%. Perfusion of islets with C. heracleifolia extract reduced insulin release by up to 47%. Although the relation between GDH activity and insulin release remains to be clarified, our results suggest that C. heracleifolia extract regulates insulin release by altering GDH activity in primary cultured islets and that this natural compound may be used to modulate GDH activity in patients with hyperinsulinism-hyperammonemia syndrome.

Animals↗