Initial Ammonia Level Research Articles

Evaluation of the Frequency of Blood Ammonia Test Requests in Pediatric Clinics Before and After the Establishment of the Pediatric Metabolism Department

Abstract Background/Aims: Hyperammonemia causes severe mortality and morbidity when left unnoticed. We aimed to compare the number of ammonia test requests before and after establishing the Pediatric Metabolism Department (PMD) in a pediatric clinic. Methods: The study was conducted retrospectively between 15/11/2022-16/11/2023. Study data were evaluated before (pre-group) and after (post-group) the establishment of PMD. Results: Two hundred eighty-five admissions were assessed in the study. There were 99 admissions in the pre-group and 186 in the post-group. There were 17 admissions for different reasons in the pre-group and 29 in the post-group. The most common reasons for admission were elevated transaminases, seizures, vomiting, and metabolic acidosis. Definitive diagnosis was made in 16 (17.6%) patients admitted in the pre-group and 39 (23.8%) in the post-group. The most common diagnoses were genetic syndromes, mitochondrial diseases, and organic acidemias. Twenty-one patients were diagnosed with inherited metabolic diseases (IMDs). Mitochondrial diseases were the most commonly diagnosed IMD (8(38%)). An ammonia test was requested from 8 of 15 pediatric subunits in the pre-group and 13 in the post-group. In the pre-group, the pediatric subunit where ammonia was requested the most was the Pediatric Neurology Polyclinic (n=25 (25.3%)). In the post-group, the subunit that required the highest number of ammonia tests was the PMD (68(23.9%)). In the ROC analysis conducted for the predictive power of the initial ammonia level in requesting a control ammonia test, the area under the curve is 0.927, and the p-value is 0.001. For the cut-off value of 60.3 µmol/l, the sensitivity was 90.9%, and the specificity was 88.6%. Conclusions: After the establishment of PMD, an increase in ammonia test requests, in the diversity of reasons for requesting ammonia testing from admissions, and in IMD diagnosis were detected, and the positive effect of PMD on pediatricians' awareness of hyperammonemia was found.

Improved two-reactor system with sulfonated membranes in wastewater treatment

The ion exchange membrane bioreactor with two-reactor system has gained attention because it has been known to be beneficial to the simultaneous removal of organic and nitrogen. However, this system has a disadvantage for accumulation of nitrate in nitrification due to low diffusivity of nitrate through a cation exchange membrane. To resolve this problem, this study proposed a unique membrane bioreactor system bounded sulfonate membrane to be applied for simultaneous removal of organic and nitrogen in wastewater. The unique membrane bioreactor system consists of two reactors called reactors A and B. The reactor A was maintained in anoxic condition while the reactor B was operated in aerobic condition during the operation period. In ammonium migration experiment, the ammonium migration rates were determined by measuring ammonium concentrations in reactor A. As a result of the measurement, the maximum mass fluxes at the initial ammonia levels of 500, 1000, 1500, and 2000 mg N/L resulted in 1.03, 2.06, 2.98, and 3.87 mg/m2• s, respectively. Those high fluxes indicated that the unique membrane bioreactor exhibited high ion diffusivity. The mass fluxes of ammonia nitrogen in this system were strongly correlated to the initial concentrations of ammonia. The nitrate produced in the reactor B by biological nitrification was effectively migrated to the reactor A, and then the migrated nitrate in the reactor A was converted to nitrogen gas by denitrifying bacteria. As a result, almost complete nitrogen removal efficiency was achieved as 99% in the batch system. Further interestingly, no severe nitrate accumulation problem was observed in reactor B in the unique membrane bioreactor, although such a problem commonly exists in the conventional cation exchange membrane bioreactor system. It is expected that this unique membrane system can be operated with low operation costs and high removal efficiencies of ammonia nitrogen.

Management of 35 critically ill hyperammonemic neonates: Role of early administration of metabolite scavengers and continuous hemodialysis

Neurological involvement is frequent in inherited metabolic disease of the intoxication type. Hyperammonemic coma related to these diseases may cause severe neurological sequelae. Early optimal treatment is mandatory combining metabolite scavengers (MS) and sometimes continuous veno-venous hemodialysis (CVVHD). We aimed to describe the therapeutic management of hyperammonemia in neonates upon diagnosis of their metabolic disease and to compare neonates managed with MS alone or with both MS and CVVHD. We conducted a retrospective study including all neonates admitted for initial hyperammonemia to the pediatric intensive care unit of a Reference Center of Inherited Metabolic Diseases, between 2001 and 2012. The study included 35 neonates. Before admission, MS were initiated for 11 neonates. At admission, the median ammonia levels were 391 μmol/L and were significantly lower in neonates who received MS before admission. At admission, ammonia levels were 644 μmol/L in dialyzed and 283 μmol/L in non-dialyzed neonates. The median time to reach a 50% decrease of the initial ammonia levels was significantly shorter in dialyzed neonates; however, the normalization of ammonia levels was similar between dialyzed and non-dialyzed neonates. Hemodynamic disorders were more frequent in dialyzed neonates. ConclusionMS represent an effective treatment for hyperammonemia and should be available in all pediatric units to avoid the need for CVVHD. Although CVVHD enhances the kinetics of toxic metabolite decrease, it is associated with adverse hemodynamic effects.

Optimal Prescriptions of Continuous Renal Replacement Therapy in Neonates with Hyperammonemia

Background/Aims: The aim of this study was to evaluate patients’ outcomes, determine the prescriptions of continuous renal replacement therapy (CRRT) that effectively reduce serum ammonia levels, and analyze the prognostic factors in neonates with hyperammonemia. Methods: The medical records of 12 Korean neonates with inborn error of metabolism (IEM) who underwent CRRT for hyperammonemia were retrospectively analyzed. Results: All patients received continuous venovenous hemodiafiltration. The median ultrafiltration rate (UFR) at the initiation of CRRT was 2,288.4 mL/h/1.73 m². The median ammonia level at CRRT initiation was 1,320 µmol/L, and the median time to reduce the initial ammonia level by at least 50% was 12.8 h. The survival rate during hospitalization was 83.3%. There were significant differences between patients with neurologic sequelae and those without poor outcomes in peak serum ammonia level before CRRT and serum ammonia level at CRRT initiation. Conclusion: This study suggested that CRRT could be a therapeutic option for neonates with IEM. However, it is necessary to raise the UFR above 4,000 mL/h/1.73 m² in patients with high initial ammonia level.

Current as an indicator of ammonia concentration during wastewater treatment in an integrated microbial electrolysis cell - Nitrification system

A key challenge for ammonia monitoring during nitrogen removal process is the extra cost and toxic reagent consuming. Herein the feasibility of current generated by an integrated microbial electrolysis cell (MEC) - nitrification reactor as an indicator of initial ammonia levels (NH3/NH4+) in wastewater was explored. In this loop system, ammonia was first oxidized to nitrate in the nitrification reactor, and then the effluent was introduced into the cathode of MEC where nitrate was reduced as electron acceptor. The correlation between current and ammonia concentration was first investigated with synthetic ammonia-rich wastewater. A good linear relationship (R2 = 0.9419) was observed between current (0.5130–3.906 mA) and ammonia levels (0–62.1 mg NH4+-N/L). Such linear relationship was always obtained regardless of the tested external power supply or wastewater pH. The external electrochemical cell was proved to be an effective pre-conditioning method to remove the disturbance from other possible electron acceptors. Finally, the integrated system was further tested with real waste streams and the results showed no significant difference (p > 0.05) with measurements by conventional methods. This study, for the first time, demonstrated the potential application of the integrated MEC - nitrification system for ammonia monitoring in addition to water treatment.

A Case of Status-Epilepticus-Associated Transient Hyperammonemia in the Emergency Department

This report describes a case of transient hyperammonemia following tonic-clonic status epilepticus with an initial ammonia level of 537 Umol/L. This appears to be the highest transient ammonia level reported in the literature in this clinical scenario. This is an affirmation that an initial elevated ammonia level in the absence of hepatic dysfunction should be interpreted with caution when associated with status epilepticus. Repeat levels should be drawn to identify transient hyperammonemia and determine the need for treatment if levels do not decrease.

GRP-074 Frequency of Valproic Acid-Induced Hyperammonemia in Adult Psychiatric Settings

BackgroundValproic acid (VPA) is widely prescribed by paediatric neurologists as an antiepileptic drug. VPA-induced hyperammonaemia can lead to encephalopathy and coma; it is well documented among the paediatric population. Severe...

Influence of pre-slaughter resting time on shelf life and ammonia level of young bull meat during the storage

The aim of present study was to evaluate the impact of pre-slaughter resting time of Simmental fattened bulls (n=40, age 14 to 24 months, m=250-350 kg) on shelf life and ammonia level of obtained meat. Animals were transported 140 km to local slaughterhouse, within two groups. First one included farm raised animals slaughtered immediately after arrival, while the second group consisted of extensively raised animals rested 36 hours prior to slaughter. The content of ammonia was measured at 1st, 3rd, 5th, 7th and 9th day of cold storage (2– 4 o ; C) in m. longissimus dorsi and m. gracilis. Initial ammonia level as well as ammonia levels measured during the storage in both muscles were higher in group of animals slaughtered immediately after arrival comparing to group of animals rested 36 hours prior to slaughter (P<0.001). At the end of storage period, meat became rotten in both groups leading us to conclude that 36 hours of resting prior to slaughter is not long enough to sufficiently suppress negative influence of stress on shelf life of meat.

In vitro and in vivo study of glutamate dehydrogenase encapsulated into mouse erythrocytes by a hypotonic dialysis procedure

Glutamate dehydrogenase (GDH) has been encapsulated into mouse erythrocytes by a hypotonic dialysis/isotonic resealing method. Although a low GDH entrapment yield was achieved (3.8%), this percentage appeared sufficient enough to metabolize high quantities of ammonia. Carrier cell recovery yield was 56%. Due to the decrease in cell volume and haemoglobin content, constant mean cell haemoglobin concentration (MCHC) values were obtained. The osmotic fragility curves (OFC) indicated that dialyzed/resealed-RBCs are more resistant to hypotonic haemolysis than native-RBCs. The successful in vitro ammonia degradation by GDH-RBCs was reflected in its total disappearance from the incubation medium at around 48 h. In contrast, initial ammonia levels were not affected during the incubation in the presence of native-RBCs and remained constant. Two different methods were used for the preparation of hyperammonaemic mice model. Since the intraperitoneal (i.p.) administration of ammonium acetate produced high ammonia levels that lasted only a few minutes, the i.p. administration of urease was chosen, given that it generated elevated ammonia levels for longer periods of time. Hyperammonaemic mice quickly removed high levels of circulating ammonia in the presence of GDH-RBCs, whereas in the presence of native-RBCs ammonia was slowly metabolized. These results suggest that loaded GDH-erythrocytes can be used as a potential carrier systems for the in vivo removal of high levels of ammonia from blood.

Breath ammonia depletion and its relevance to acidic aerosol exposure studies.

It is thought that gaseous ammonia in breath neutralizes acidic air pollution and thereby potentially mitigates the pulmonary effects of pollution. The efficacy of breath ammonia depletion methods reported in recent acid aerosol exposure-health response studies was investigated. Fourteen subjects (21 to 54 y of age) performed one or more of the following hygiene maneuvers: (a) acidic oral rinse (pH 2.5); (b) tooth brushing, followed by acidic oral rinse; (c) tooth brushing, followed by distilled water rinse; and (d) distilled water rinse. Initial ammonia levels ranged from 120 to 1,280 ppb (147-1,570 micrograms/m3). Acidic rinsing resulted in an immediate 90% reduction in exhaled ammonia in all subjects, and a return to 50% of baseline levels occurred within 1 h. Depletion that resulted from tooth brushing or distilled water alone was not significant. It was concluded that acidic oral rinsing is an effective method of reducing airway ammonia, but repeated oral rinsing may be required to maintain consistent, low-breath-ammonia conditions during acid aerosol exposure studies.

Some factors involved in Phase II of mushroom compost preparation

Temperature, initial ammonia levels and aeration were found to be major factors determining the time required to complete the Phase II stage of mushroom compost preparation. Ammonia disappeared most rapidly in the region of 40–45°C, though disappearance was still relatively fast over the range 35–50°C. As temperatures rose above 50°C, the rate of disappearance of ammonia slowed down considerably, and above 55°C a different pattern of change in ammonia levels with time was revealed, with a rapid initial fall being followed by a long slow decline. At these higher temperatures, and also at 40°C or below, the final composts were not selective and supported the growth of competitor fungi as well as the mushroom. Selective composts were produced over the range 45–55°C, though much more time was required to complete Phase II towards the top of this range. The initial levels of ammonia in the compost also affected the time required to complete Phase II, with the higher initial levels requiring more time. Aeration was also an important factor. A reduction of average oxygen levels from 19 to 14%, accompanied by a corresponding increase in carbon dioxide levels, almost doubled the time required to complete Phase II. The results indicated an active involvement in the Phase II process of the thermophilic microflora in the compost.