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A novel approach is reported for the removal of ammonium formed from the conversion of urea by urease. By alkalinization, ammonium is converted into free ammonia. Free ammonia can then be very easily removed by a number of approaches: as gaseous ammonia by air bubbling, oxygenator, or air ventilation; by adsorbent for free ammonia; or other approaches.
It has been determined of 70 liver-healthy probands the ammonia concentration of capillary blood after poor on protein respectively rich on proteine food in 30 minutes distances. It comes in both groups to a spontaneous ascent the concentration of ammonia. The highest ammonia concentration depends on the content of protein which has been taken through food and the descent also variable quick. For it amount to the waiting period of food on the determination of blood ammonia after in frontly poor on protein food 90 minutes and after in frontly rich on protein food three hours. The statements have been secured statisticaly by means of U-test.
Cheviot wethers were defaunated by using dioctyl sodium sulfosuccinate and were constantly infused with urea to provide 2.87% of the daily N intake. Defaunation resulted in higher rumen dry matter and lower rumen pH. The molar per cent propionate was higher in defaunated sheep, whereas the molar per cent butyrate and acetate was lower. Apparent nitrogen digestibility, nitrogen utilization, and nitrogen balance were higher in defaunated sheep when compared with faunated animals. Urea infusion resulted in lower apparent nitrogen digestibility, nitrogen utilization, and nitrogen balance in faunated sheep, but did not affect nitrogen metabolism in defaunated sheep. Rumen ammonia-N levels in defaunated sheep were lower than those observed for faunated animals, and urea infusion into faunated sheep increased rumen ammonia-N levels to a greater extent than did the urea infusion into defaunated animals. Significant correlations were demonstrated between rumen ammonia-N levels and C(2)/C(3), C(3)/C(4) and C(2)/C(4) volatile acid ratios. From this it was concluded that, as rumen ammonia-N levels increased, there was a shift from propionate to higher proportions of butyrate and acetate.
In order to evaluate the ammonia, glutamine, and alanine muscular uptake and/or release, we have studied the effects of ammonium acetate perfusions, in intact anaesthetized rat hindquarters, by simultaneous measure of blood flow and arterio-venous differences of ammonia, glutamine and alanine concentrations. Increasing doses of ammonium acetate perfusions (1.23-2.46-3.69 nmol/mm/100 g b.w.) result in an increase of ammonia rat hindquarters uptake which is correlated with the amount of ammonium infused and the arterial ammonia levels but without significant release or uptake of glutamine or alanine. However these perfusions induce an arterial hyperglutaminemia and hypoalaninemia likely due to extramuscular metabolic changes in these two amino-acids.
In 16 children and adolescents suffering from mucoviscidosis the ammonia concentration of the plasma determined by a modified ion exchange method was compared with the clinical degree of severity. The ammonia values of the plasma were compared with several parameters, such as Shwachman stage, the presence of cardio-respiratory insufficiency, blood gas values and liver function tests. In 5 children with cystic fibrosis and cardio-respiratory insufficiency high plasma ammonia values were found. In older children with the disease lasting for a longer time with medium Shwachman stage (stage III) but without cardiorespiratory insufficiency the ammonia values were also relatively high. Cardiorespiratory insufficiency and disturbance of the liver function may play a role in the development of hyperammonemia. A distinct hyperammonemia refers to a bad prognosis in children with cystic fibrosis.
The purpose of the study was to examine the effects of whole gut mannitol irrigation on arterial blood ammonia and plasma aminoacids in cirrhotic patients with bleeding oesophageal varices and its influence on post-haemorrhagic encephalopathy. The 28 patients studied were divided at random into two groups: group I, non-irrigated (n = 16) and group II, irrigated (n = 12). In all cases bleeding was controlled by a Blakemore haemostatic tube which enabled irrigation to be performed in group II subjects. Four hours after starting irrigation a significant decrease in arterial blood ammonia became apparent in group II patients as compared with controls (p < 0.05). After 24 hours, blood ammonia had decreased in both groups but was significantly lower in group II patients than in group I patients (p < 0.01). No significant change in branched chain aminoacids to aromatic aminoacids molar ratio was observed in either group. Clinically, mannitol irrigation had a significantly (p < 0.01) favourable effect in preventing the development or aggravation of posthaemorrhagic encephalopathy, which suggests that toxic substances of intestinal origin, particularly ammonia, may intervene in the pathogenesis of this condition.
The effect of Ca2+ ions on carbamoylphosphate synthetase (ammonia) (EC 6.3.4.16) of rat liver mitochondria was studied. In lysed mitochondria, carbamoylphosphate synthetase (ammonia) was inhibited by Ca2+ ions. In intact rat liver mitochondria, the rate of citrulline production from added ammonia, ornithine, and bicarbonate was inversely correlated with the magnitude of the intramitochondrial concentration of Ca2+. This effect was found at concentrations of Ca2+ which are within the physiological range. The inhibition was reversed by added Mg2+ and was not due to effects of Ca2+ on mitochondrial energy production. It is proposed that the activity of carbamoylphosphate synthetase (ammonia) may be modulated in vivo by changes in the concentration of Ca2+ ions in the mitochondrial matrix.
Ammonia is an important chemical in industry. Accidental inhalation of ammonia has resulted in upper airway and bronchoalveolar injury, and even fatal inhalation of anhydrous ammonia has occurred. We present herein a 5-year follow-up on a patient who had no prior history of smoking or pulmonary symptoms and had overwhelming exposure to ammonia which resulted in acute respiratory failure with diffuse lung parenchymal and airway involvement. The extreme inflammation and desquamation of the mucosa of the central bronchial tree, as observed bronchoscopically, have apparently resulted in a hyperreactive bronchoconstrictive component. Because our patient had never smoked and had no history of pulmonary symptoms or wheezing, we speculate that both the central and the peripheral residual airway obstructions were a result of his inhalation injury. In addition, peripheral airway disease, suggested by the postbronchodilator flow-volume curves present during the first year of follow-up, has gradually cleared even though there is evidence of parenchymal scarring.
Long-term follow-up of the pulmonary lesions of severe exposure to ammonia in humans has seldom been documented, and development of bronchiectasis continues to be of concern. We studied a previously healthy 30-year-old woman whose lungs at time of necropsy, three years after massive exposure to ammonia fumes, had extensive cylindrical and saccular bronchiectasis. We concluded that massive exposure to ammonia can lead to bronchiectasis. It is not known, however, whether the bronchiectasis resulted from chemical injury by ammonia or from a superimposed bacterial bronchitis.
It is dealt with an ammonia-selective membrane electrode for the quantitative determination of volatile amines and ammonia released from rubber caps of containers for parenteral solutions. The optimal measurement parameters were determined. It was demonstrated that the electrode is well suited for ammonia determinations in the range of 10(-6) to 10(-1) mol/l. As this method requires but little time and yields accurate results, it will be helpful in laboratories with heavy routine workloads. Fifteen different caps based on natural rubber, chlorobutyl rubber or bromobutyl rubber were tested for their usefulness as packaging materials for drugs. According to the amounts of released ammonia, the caps were classified into three categories.
Measurements of blood ammonia and methanethiol were made in 17 moderate or severe alcoholic cirrhotics without overt hepatic encephalopathy under fasting conditions and 2, 3 1/2 and 5 hours after ingestion of a hamburger containing 80 gm. protein. At every time interval the average blood methanethiol in the cirrhotics was significantly higher than in 11 normal controls. The average blood ammonia in the cirrhotics was also higher than in the controls but only at five hours was the difference statistically significant. Fasting blood ammonia and methanethiol values were not strikingly effective in separating the normals and cirrhotics. After the protein load, however, the peak values of these measurements completely separated the cirrhotics from normals on a two-dimensional plot of methanethiol vs. ammonia. In our sample of patients, the peak postprotein load measurements were not effective in predicting which cirrhotics may develop overt encephalopathy. Utilization of the area under the curve of values obtained after the protein load did not appreciably improve on the results with the single peak value.
The pathways of ammonia neutralization in the rat heart muscle were traced with nitrogen-15 isotope. The effect of ammonia concentration in the perfusate on its utilization by the myocardium was investigated over the range of 1.6--3.4 mM. Considerable amounts of the neutralized ammonia were found in glutamine and glutamic acid, less quantities in alanine and aspartic acid. Isoproterenol-induced necrosis of the heart muscle leads to a decrease in both glutamine and alanine ability to bind ammonia (20--40 and 30--45%, respectively). The necrosis effect is not significant for glutamic acid. In necrosis nitrogen-15 incorporation into aspartic acid declines whereas with higher concentrations it significantly increases.
UNLABELLED: The posterolateral defect is a common artifact seen when static 13N-ammonia imaging with PET is used to assess myocardial perfusion. The aim of this study was to compare dynamic and static. 13N-ammonia PET and to obtain more insight into the cause of the posterolateral defect. METHODS: Dynamic 13N-ammonia PET was performed in 19 healthy nonsmoking volunteers at rest. Perfusion was assessed in the early phase of the study using a curve fit method over the first 90 sec. Nitrogen-13 accumulation (static PET) was assessed 4 to 8 min after injection. Each study was normalized to a mean of 100. The average distribution of normalized perfusion and activity was calculated in 24 segments. Heterogeneity of both activity and perfusion distribution were assessed and the activity distribution was compared with perfusion distribution. RESULTS: Perfusion distribution was homogeneous, with the exception of the inferior and apical regions. Activity distribution was inhomogeneous, with a lower activity in the posterolateral and apical regions. In the whole left ventricle, significant differences in distribution were found between static and dynamic imaging. CONCLUSION: Perfusion distribution was significantly different on dynamic images compared to static images. The posterolateral defect was not found on dynamic images. The posterolateral defect and other inhomogeneities in activity distribution are caused by tracer-dependent features, probably a redistribution of metabolites of 13N-ammonia.
The mucosa of 46 patients with histological chronic gastritis were cultured for helicobacter pylori (HP) and the ammonia and urea in their gastric juice were also determined. The results showed the average ammonia concentration (1.22 +/- 0.23 mmol/L) in HP positive patients was higher than that of HP negative patients (0.72 +/- 0.25 mmol/L), (P < 0.05). But the average urea concentration (0.45 +/- 0.29 mmol/L) in HP positive patients was lower than that of HP negative patients (2.71 +/- 1.20 mmol/L), (P < 0.05). The higher the level of ammonia stands, the more severe the gastritis is. (rs = 0.556). On the other hand, the quantity of mucus was elevated in 18 patients among 28 patients with HP eradicated by drug treatment, which was significantly different from the patients with HP not eradicated. It is suggested that the epithelium of gastric mucosa and the mucus are the chief components of the gastric mucosa barrier; the presence of HP increases ammonia, and thus damages the gastric epithelium and reduces the quantity of mucus. Consequently, the protective gastric mucosa barrier is damaged, and then comes the liability to HP-associated gastritis.
Levels of plasma amino acids, ammonia, glucagon and insulin and their 5-hr responses to a protein feeding were evaluated before and sequentially (3 mo and 1 yr) after distal splenorenal shunt in 10 patients with cirrhosis belonging to Child-Pugh's class A or B. An index of glucagon effectiveness (plasma glucose/glucagon) was also calculated. These parameters were related to liver test results, portal vein diameter and mental state, and they were compared with those found in seven patients undergoing sclerotherapy of esophageal varices with comparable liver function (control group). Liver test results and levels of plasma insulin did not change in either group. Shunt significantly increased levels of fasting tyrosine, methionine, ornithine, arginine, histidine, ammonia and glucagon with respect to the control group; it also significantly decreased levels of leucine, valine, glucagon effectiveness and portal vein diameter. The elevation of levels of tyrosine, ammonia and the sum of arginine and ornithine was correlated directly with the increase in glucagon and inversely with the decline in glucagon effectiveness. Tyrosine increase was also correlated with the reduction of portal vein diameter. One shunted patient showed mild hepatic encephalopathy. Protein feeding did not worsen the mental state of patients before and after the operation. Surgery significantly increased the 5-hr response to the meal of gluconeogenic amino acids; its rise was again correlated with the changes in glucagon plasma levels and effectiveness. Although the absorptive levels of plasma ammonia were significantly higher 1 yr after surgery, its 5-hr response barely rose. In cirrhotic patients with a relatively preserved liver function, distal splenorenal shunt progressively worsened the fasting plasma profile of nitrogen compounds and the response to protein ingestion of gluconeogenic amino acids. The decline of portal blood flow and glucagon effectiveness may be causal factors. Despite this, the "cerebral" tolerance to a moderate oral load of protein was not reduced by surgery.
Positron emission tomography has been shown to provide quantitative estimates of myocardial blood flow using 13N-ammonia and 15O-water. In a validation study, myocardial blood flow was noninvasively determined in 11 open-chest anesthetized dogs using dynamic positron emission tomography. The radiopharmaceuticals 13N-ammonia and 15O-water were intravenously administered and measurements were carried out at rest and following pharmacological vasodilation to assess blood flow over a range from 53 to 580 ml/100 g/min. Quantification of blood flow based on tracer kinetic modeling of 13N-ammonia data correlated closely with myocardial blood flow determined by microspheres (y = 0.944 x +7.22, r = 0.986) and with the 15O-water injection technique y = 1.054 x -15.8 (r = 0.99). The use of 13N-ammonia with positron emission tomography enables the accurate quantification of myocardial blood flow. Using this technique, uncomplicated study protocols simplify the measurement procedures while providing excellent qualitative and quantitative information.
Ammonia emissions from animal farming have negative effects inside and outside of animal housings. Numerous feed or slurry additives are offered to reduce the ammonia emissions from pig keeping. Investigations were carried out to test the effectiveness of a clinoptilotite-containing feed additive named "Klinofeed" on practical farms and in laboratory experiments. Some effects of ammonium retention were seen in the laboratory tests, which also revealed informations on the absorption mechanisms of ammonium ions. The field experiments didn't show any ammonia reducing effect of the additive. It is recommended to develop a standardized procedure of testing the effectivity and usefulness of feed and slurry additives which are manufactured and sold for ammonia reduction purposes. The presented experiment could be a first basis for such a test procedure.
Results of continuous measurements of ammonia during three rounds with a total number of 297 days (appr. 7000 hour-values) and of behavioural investigations over 576 hours in two rounds at the begin, in the middle and at the end of fattening period have shown a high congruence of both variables (concentrations of ammonia; percentage of using self-feeders as indicator for animal activity) over 24 hour-cycle with a characteristic biphasic dynamics and two periods of increased values (after morning feeding between 7 and 9 a.m. and in the afternoon between 1 and 3 p.m.). The hour-averages of both parameters demonstrated a high significant positive correlation (r = 0.83; p < 0.01): concentration of ammonia is increasing with increasing animal activity. To evaluate concentration or emission of ammonia under the view point of animal or environmental hygiene it is necessary to consider the dynamics of NH3-values in choosing representative measurement points or periods.