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At least 235 records · Page 13Linked to original sources
PubMed1992

Transient hyperammonemia of the newborn: a vascular complication of prematurity?

Transient hyperammonemia of the newborn is an overwhelming disease manifested by hyperammonemic coma in ill premature infants. A summary of evidence is presented supporting the hypothesis that this syndrome is a vascular complication caused by shunting of blood away from the portal circulation of the liver into the systemic circulation with subsequent lack of ammonia removal. Alternative, nontraditional approaches of investigation and therapy targeting the hepatic portal circulation should be explored in patients with transient hyperammonemia of the newborn.

Ammonia↗
PubMed1992

Nonketotic hyperglycinemia presenting with pin-point pupils and hyperammonemia.

We describe two siblings who presented with lethargy, decreased sucking, respiratory failure and seizures in their first days of life. Pin-point pupils were noted in both siblings. Amino acid analysis revealed elevated concentrations of glycine in plasma and cerebrospinal fluid (CSF), with abnormal CSF/plasma ratios, compatible with hyperglycinemia. Urine organic acid analysis was unremarkable. Hyperammonemia was found in both siblings, but this subsided within 24-72 h. We suggest that pin-point pupils may be an additional presenting sign of nonketotic hyperglycinemia and, if looked for early enough, hyperammonemia may be found in this disorder.

Ammonia↗
PubMed1991

[Positron emission tomography (PET) before and after treatment of hyperammonemia in a patient with decompensated liver cirrhosis].

A 56 year-old-male liver cirrhosis patient was admitted because of hepatic encephalopathy with hyperammonemia. We measured cerebral blood flow (CBF), cerebral oxygen extraction fraction (OEF) and cerebral metabolic rate for oxygen (CMRO2) by using PET before and after treatment of hyperammonemia. At the time of the first PET, serum ammonia was 152 micrograms/dl and on the second PET it was 88 micrograms/dl. The electroencephalogram and number connection test also improved on the second PET. CBF and CMRO2 were decreased by 25-42% in comparison to normal control and OEF increased 1-24% at first examination. Similar abnormal reduction of both CBF and CMRO2 and increase of OEF were seen at second examination. Reduced CBF and CMRO2 regardless of serum ammonia level suggests that heptic encephalopathy may be, at least in part, associated with pathological changes in brain tissue induced by hepatic metabolic disorder.

Ammonia↗
PubMed1991

[The problems of valproate therapy in severely handicapped children--valproate induced hyperammonemia and hypocarnitinemia].

Blood ammonia and serum free carnitine were measured in 49 severely handicapped epileptic patients treated with or without valproate. DL- or L-carnitine were administered to patients treated with valproate, and the effects of carnitine supplementation were evaluated. Furthermore we analyzed the relationship between serum free carnitine and nutrition. In patients treated with valproate, blood ammonia statistically increased, and serum free carnitine concentration statistically decreased. Free carnitine was low in tube-fed patients, as compared with that in oral-fed patients. Carnitine therapy was successful in improvement of hyperammonemia and hypocarnitinemia. It is concluded that hypocarnitinemia was caused not only by valproate therapy, but also by tube-feeding. Carnitine supplementation therapy is important to both hyperammonemia and hypocarnitinemia. But the long term effect of carnitine therapy remains to be studied further.

Adolescent↗
PubMed1991

[Non-secretory primary plasma cell leukemia with hyperammonemia].

A 78-year-old man was admitted because of lumbago and chest pain. A diagnosis of non-secretory primary plasma cell leukemia was made based on the laboratory findings and his history. However, the plaque-forming cells assay of bone marrow cells revealed secretion of monoclonal immunoglobulin from the myeloma cells. Hyperammonemia was detected in the serum. Although the patient was treated with 4 courses of combination chemotherapy (vincristine, adriamycin, cyclophosphamide, methylprednisolone), he died of respiratory failure five months after diagnosis. Autopsy showed widespread multiple myeloma and prominent infiltration of myeloma cell in the sinusoid of the liver. Recently, there have been a few reports which increased the plasma ammonia concentration with multiple myeloma. This report strongly suggested that liver infiltration of myeloma cell caused hyperammonemia.

Aged↗
PubMed1990

[Anesthetic experience of a patient for splenectomy with severe liver dysfunction and hyperammonemia].

A case of a patient with severe liver dysfunction and hyperammonemia undergoing splenectomy and liver biopsy was reported. Preoperative examination revealed that this patient's liver function was severely impaired due to liver cirrhosis (ICG15 = 60%, HPT = 29%, serum NH3 = 110 micrograms.dl-1). Preoperatively, kanamycin 2 g.day-1 and lacturose 60 ml.day-1 were given and FFP 3-5 units.day-1 were infused. With no premedication, general anesthesia was induced with dTc 3 mg, thiopental 200 mg and SCC 80 mg. Anesthesia was maintained with N2O-O2-enflurane and pancuronium. Though N2O concentration was kept at 50% to prevent intraoperative hypoxemia, the necessary enflurane concentration was low (almost 1% or lower). Serum NH3 level during operation was stable (100-110 micrograms.dl-1), and the level decreased (66-90 micrograms.dl-1) postoperatively. Postoperatively, this patient's consciousness level fluctuated with or without flapping tremor. The treatment of hepatic encephalopathy with lactulose, aminoleban EN and maalox were effective. Problems of perioperative and anesthetic management of a patient for upper abdominal surgery with severe liver dysfunction associated with hyperammonemia were discussed.

Ammonia↗
PubMed1987

[Hyperammonemia induced by propranolol in cirrhotic patients. Role of the kidney and influence of the severity of the cirrhosis].

The effect of the intravenous injection of 0.1 mg/kg of propranolol on arterial ammonemia was studied in 30 patients with alcoholic cirrhosis comparatively with 10 healthy volunteers. Moreover, in 20 patients in the cirrhotic group (10 were Pugh's grade A or B and 10 others were grade C), left renal vein catheterization was performed to follow the changes in ammonemia and glutaminemia levels simultaneously with those occurring in arterial blood. After 30 min, arterial ammonemia was significantly increased in the controls (p less than 0.02) and in the cirrhotic patients (p less than 0.001). The renal venous ammonemia was also significantly increased in all of the cirrhotic patients (p less than 0.01). In the grade A and B patients, the increase in ammonemia was more marked in the renal vein as compared with that in arterial blood (p less than 0.001). In contrast, in the grade C patients, the increase in ammonemia did not differ significantly between the two sectors. The difference in ammonia concentration between arterial and renal venous blood increased significantly after 30 min in the grade A and B patients (p less than 0.001) whereas it was stable in the grade C patients. The changes of glutaminemia in arterial and renal venous blood were not significantly different in the two groups of cirrhotic patients. These data show that, in our experimental conditions, propranolol induces arterial hyperammonemia in cirrhotic patients and that the kidney could interfere with the mechanism of hyperammonemia, at least in grade A and B patients.

Ammonia↗
PubMed1978

[Alterations in thyroid hormones and thyrotropin response to TRH in cirrhotic patients with or without hyperammonemia (author's transl)].

Serum concentrations of thyroid hormones and TSH response to TRH are studied in normal controls and in patients with liver cirrhosis. T3 levels are significantly diminished in the cirrhotic group while the mean total T4 concentration, the basal TSH and the magnitude of the peak response to TRH are similar in cirrhotic and control patients. However when the cirrhotic patients are separated in two groups according to the level of arterial ammonemia, it appears that the group with hyperammonemia (n = 10) has a significantly higher peak response than the control group. Since hyperammonemia is a wittness of hepatic encephalopathy it is suggested that TSH release or synthesis may be modified by this situation resulting from a cerebral accumulation of false neurotransmitters and a depletion of aminergic mediators.

Ammonia↗
PubMed1979

Hyperammonemia associated with perinatal asphyxia.

Twelve infants with severe perinatal asphyxia were found to have elevated blood ammonia levels (302 to 960 microgram/100 ml). In the seven survivors, hyperammonemia was associated with CNS irritability, hyperthermia, hypertension, and wide neonatal heart rate oscillations. Follow-up examinations revealed severe neurologic dysfunction in five of seven infants. CNS depression, hyperthermia, hypertension, and a nonreactive, fixed heart rate characterized the infants that died. These findings suggest a clinical entity secondary to perinatal asphyxia whose signs and symptoms may be related to hyperammonemia.

Ammonia↗
PubMed1984

Modification of drug action by hyperammonemia.

Pretreatment with ammonium acetate (NH4Ac) (6 mmol/kg s.c.) approximately doubled the time morphine-treated mice remained on a hot surface and similarly increased muscular incoordination by diazepam, but NH4Ac treatment alone had no effect. Thus, hyperammonemia is capable of altering drug action and must be considered along with impaired drug metabolism in enhanced drug responses associated with liver disease. Experiments in vitro showed that acetylcholine-induced catecholamine release from bovine adrenal medulla is depressed as much as 50% by 0.3 mM NH4Ac and KCl-induced contractions of guinea-pig ileum were inhibited 20% by 5 mM NH4Ac. Addition of excess calcium reversed the depression in both tissues, but calcium-independent catecholamine release by acetaldehyde was not blocked by NH4Ac. These results suggested that ammonia blocks calcium channels. Parallels in the actions of NH4Ac and the calcium channel blocker verapamil support this concept. Both verapamil (10 mg/kg i.p.) and NH4Ac pretreatment enhanced morphine analgesia- and diazepam-induced muscular incoordination and antagonized amphetamine-induced motor activity, and neither verapamil nor NH4Ac affected the convulsant action of metrazol. The data suggest that hyperammonemia exerts a calcium channel blocking action which enhances the effects of central nervous system depressants and certain opioid analgesics.

Acetates↗
PubMed1980

[Effects of experimental hyperammonemia on the secretion of insulin and glucagon in the rat].

In order to investigate the controverted effect of ammonia on insulin and glucagon secretion 3 groups of 55 rats were perfused either by Na+ acetate (controls), either by NH4+ acetate: in the first group plasma insulin (IRI) and glucagon (IRG) levels were compared before and after perfusion; the second group was supplemented by glucose perfusion (1 g/100 g/hour); in the last group an arginine perfusion (1 g/kg/min) was started 15 min after the beginning of NH4+ or Na acetate and IRI and IRG levels were determined in the portal blood. Hyperammonemia, which reached about 500 microgram/dl, reduced significantly the IRI portal level and the IRI secretion induced by glucose or arginine, whereas basal or stimulated IRG levels are not modified. The ratio IRI:IRG is diminished in each group perfused with NH4+ acetate. Our results show that ammonia inhibits insulin without modifications in the glucagon secretion; hyperglucagonemia and hyperinsulinism reported in hepatic encephalopathy with chronic hyperammonemia may not be attributed to an effect of ammonia.

Ammonia↗
PubMedDate not supplied

[Renal origin of hyperammonemia induced by an high-protein diet in normal rats or those with portal stricture].

Hyperammonemia is observed in high protein diet fed cirrhotic and is thought to be related to an increased intestinal ammoniagenesis. We studied this problem in control rats and rats with a portal stricture and portal systemic shunts given a high protein or a standard diet. In those animals the systemic, portal and renal venous ammonemia and glutaminemia were measured. In rats with portal stricture on a high protein diet, the increase in systemic ammonemia did not significantly differ from that found in animals on a standard diet. In contrast, the control group exhibited a higher level (P less than 0.001) of systemic ammonemia after a high protein (102 +/- 7 SEM mumol/l) than after standard diet (36 +/- 1). This hyperammonemia appeared to be of renal origin since there was a significantly higher ammonia difference between renal venous and arterial blood with the high protein than with standard feeding, both in rats with a portal stricture (+ 229 +/- 32 vs. + 24 +/- 8 mumol/l; P less than 0.001). and in control rats (+ 196 +/- 23 vs. + 2 +/- 11; P less than 0.001). This increased renal ammonia release into the circulation induced by the high protein diet was associated with a high renal uptake of circulating glutamine. Moreover, a decreased ammonia passage from the digestive tract into the portal vein and disappearance of intestinal uptake of circulating glutamine was also observed with the high protein feeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Ammonia↗
PubMed1978

Studies of the cause and treatment of hyperammonemia in females with ornithine transcarbamylase deficiency.

Assay of ornithine transcarbamylase (OTC) activity in multiple small bits of liver (approximately 5 mg) that were obtained from a single surgical biopsy in a patient with OTC deficiency revealed a 10- to 40-fold variation in enzyme activity. Similar studies with control autopsy liver specimens varied 2.5-fold at most. The greater variation in the patient with OTC deficiency probably is due to sampling of clusters of normal or abnormal hepatocytes that resulted from inactivation of either the abnormal or normal X chromosone. Enzyme activity assayed on small liver biopsy specimens may not be representative of the entire liver in female patients with OTC deficiency. The hyperammonemia in individuals heterozygous for OTC deficiency may be due in part to shunting of blood through multiple "metabolic portosystemic shunts." Treatment of a girl who has OTC deficiency with a low-protein diet, a low-protein diet supplemented with oral essential amino acids, and a low-protein diet plus oral ketoacids of essential amino acids, on a separate occasion, a low-protein diet was compared to a low-protein diet plus lactulose. The low-protein diet plus oral ketoacid supplementation resulted in the best metabolic control of the patient's disease. On the other hand, paradoxical transient hyperammonemia was observed after the intarvenous administration of ketoacids to two acutely ill female patients with OTC deficiency.

Amino Acids, Essential↗
PubMed1982

[Hyperammonemia: a suggestion for diagnostic and therapeutic procedures].

Hyperammonemia in pediatrics leads to emergency situations. Adequate decisions for treatment have to be taken rapidly. These depend on the underlying disorder. While the patient's history and symptoms should lead to a search for hyperammonemia, the further steps will depend on biochemical results of aminoacid determinations in plasma and urine, and orotic acid excretion. In some cases where this latter metabolite is not increased, the determination of organic acids in urine and enzyme assays in liver are needed. A scheme for the diagnostic and therapeutic measures is proposed.

Amino Acids↗
PubMed1981

[Hyperammonemia in the newborn through ornithine transcarbamylase deficiency (author's transl)].

This is a report of a family with hyperammonemia in the newborn, very probably due to ornithine transcarbamylase deficiency. Typically the male infant died in the newborn period within 74 hours. In the female newborn it was possible to provide a normal development with protein restricted diet. In mother's line there are unexplained death's of infants. The examination of amino acids and organic acids excluded other disturbances. The determination of orotic acid in the urines and oral loading with protein indicated to OTC-deficiency. The RDS-symptomatic and pulmonary bleeding in the newborns with hyperammonemia is emphasized.

Ammonia↗
PubMed1994

[Primary plasma cell leukemia complicated with high-output cardiac failure and hyperammonemia].

A 23-year-old male patient with plasma cell leukemia showed characteristic clinical features: accelerating heart failure and consciousness disturbance accompanied with an increase of plasma cells in peripheral blood. Evaluation of cardiac function revealed a hyperdynamic cardiac state with low somatic vascular resistance, indicating high-output cardiac failure. However no disorders causing high-output cardiac failure were found. Consciousness disturbance and hyperammonemia with serum amino acid abnormality of unknown origin were also demonstrated. After intensive combined chemotherapy (MVD + VAD), high-output cardiac failure and hyperammonemia improved with disappearance of plasma cells, suggesting that these symptoms were closely related with progression of plasma cell leukemia.

Adult↗
PubMed1993

[A case of hyperammonemia in chronic renal failure successfully treated with the infusion of NaHCO3].

The present report describes a rare of a 77-year-old woman who developed encephalopathy and metabolic acidosis associated with hyperammonemia, at the introduction of hemodialysis by chronic renal failure. With the intravenous infusion of HCO3-, levels of acidosis and hyperammonemia decreased rapidly. Concomitantly the disturbance of consciousness was improved. Results of plasma amino acid patterns of pre and post infusion of HCO3- showed improvement of the metabolism of the urea cycle, increased urea synthesis and decreased plasma ammonium levels. The role of the hepatic urea cycle has been considered to be exclusively the elimination of potentially toxic ammonia. In the conventional view, the acid base balance of the body obtains stabilized homeostasis by the function of the principal organs, lungs and kidneys. But, it has been recently shown that urea cycle is an important factor in the maintenance of pH homeostasis, due to regulated metabolism of HCO3-. Both HCO3- and NH4+ are converted to urea indicating the urea cycle's involvement in acid base homeostasis. 2HCO3- + 2NH4+-->urea+CO2+3H2O In this case, with the infusion of HCO3, the metabolism of the urea-cycle was improved and plasma ammonium levels were decreased. This indicates that HCO3- is an important factor for the metabolism of ammonia.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Emergency therapy of neonatal hyperammonemia with high dosage glucose].

In severe neonatal hyperammonemia, therapy must be started immediately to prevent irreversible CNS damage. Endogenous ammonia production can be quickly reduced if an anabolic condition is induced by means of high-dose glucose infusion. We applied this treatment to four newborn infants with hyperammonemia, this being a symptom of an inborn error of metabolism. The dangerous metabolic dysfunction was brought under control without dialysis within 24-48 hours in all four patients.

Ammonia↗