Dosage de l'ammoniemie en discontinu et en continu par une technique de dialyse automatique

Imler, M; Frick, Alice; Stahl, A; Peter, Bernard; Stahl, J

doi:10.1016/0009-8981(72)90439-1

Cited by 34 publications

(9 citation statements)

References 4 publications

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“…During the "low" NH 4 + infusion, the level increased rapidly to 250 _+ 12 ~tg/100 ml at 60 rain and to 275 _+ 15 at 95 min. These arterial levels were comparable to those usually observed in cirrhotic patients in hepatic coma [20]. This hyperammonemia was not modified by the rapid injection of glucose at the 60th min.…”

Section: Arterial Blood Ammoniasupporting

confidence: 86%

“…The blood glucose levels were measured on 0.05 ml of blood by the technique of Hoffman [18] adapted to a Technicon autoanalyzer. The ammonia was also determined on 0.05 ml of blood using a method of automatic dialysis [20]. For both of these determinations, the blood was pumped directly from the carotid of the rat to the autoanalyzer to avoid any intermediate manipulation and any excessive blood loss.…”

Section: Methodsmentioning

confidence: 99%

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Diabetogenic effect and inhibition of insulin secretion induced in normal rats by ammonium infusions

Schlienger¹,

Imler²,

Stahl³

1975

Diabetologia

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Summary. In order to explain the abnormalities of glucose metabolism previously observed in patients with blood ammonia elevation, the effect of a transitory hyperammonemia on I. V. glucose tolerance was investigated in rats. An I. V. glucose tolerance test was performed in 3 groups of 15 rats 60 min after the beginning of a 95 rain infusion of either a 2 ml isotonic NaC1 solution (control group) or ammonium acetate solutions at low (0.50 gmol/kg/min. NI-I4+ ) or high doses (1.70 ~tmol/kg/min NH4+ ). The "high" NH4+ infusion produced an increase of blood ammonia to levels near 1000 ~tg/100 ml, a significant decrease in the K coefficient for glucose disappearance (2.53 x 10-24-0.20 compared to 4.92 x 10 -a 4-0.13 in control group) and a suppression of the radioimmunological plasma insulin (I. R. I.) response to glucose.With the "low" NH 4 -/-infusion the hyperammonemia was less pronounced (200-300 gg/100 ml), but the decrease in K(3.02 x 10 -2 4-0.15) and in the first phase of I.R.I. release remained significant. The decrease in glucose disappearance rate could be accounted for by the proportional decrease in insulin secretion. Thus glucose intolerance induced by ammonium acetate infusions may be due to a direct effect of NI"I 4 "1-on the pancreas. These abnormalities in glucose metabolism depend on the quantity of infused ammonium.Key words: Rat, ammonium infusion, blood ammonia, glucose metabolism, plasma immunoreactive insulin.In 1955 Bessman et al [4] suggested that the neurotoxicity of hyperammonemia in porto-systemic encephalopathy results from a disturbance in cerebral glucose utilization. The observation, in hepatic coma, of a decrease in cerebral oxygen consumption [12,22] and an increase in some intermediates of glucose metabolism [11,35] supports this hypothesis. However the influence of variations in ammonium metabolism on the regulation of carbohydrate metabolism is still debated [10,34]. Recently, we noted that I. V. glucose tolerance was worse in cirrhotic patients with hepatic coma than in those without porto-systemic encephalopathy [30]. One factor which could explain this observation, was the increase in arterial blood ammonia which was consistently observed during hepatic coma. Thus we noted in both normal and cirrhotic subjects, infused with ammonium chloride or acetate, that a transitory elevation in arterial blood ammonia invariably brought about a very significant diminution in I. V. glucose tolerance [31] and an inhibition of the insulin secretion induced by the glucose load [32]. However, in these studies, we were unable to show any correlation between these anomalies and the blood ammonia levels. The aim of * Presented at the 9th Meeting of the European Association for the Study of the Liver. Hemsedal, Norway, september [6][7] 1974 the present study was to compare in normal rats the action of a moderate or gross hyperammonemia on glucose tolerance and insulin secretion. Material and MethodsThree groups of 15 male Wistar rats, weighing 250-300 g and fasted for 20 hours, were used. Afte...

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Section: Arterial Blood Ammoniasupporting

confidence: 86%

Section: Methodsmentioning

confidence: 99%

Diabetogenic effect and inhibition of insulin secretion induced in normal rats by ammonium infusions

Schlienger¹,

Imler²,

Stahl³

1975

Diabetologia

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“…After a critical study of the previously published methods (I), we developed in 1972 a flow dialysis technique (2) which enabled us to measure discontinuously or continuously ammonia levels in arterial and/or iri venous blood samples of at least 0.23 ml. We now report a miniaturization of the technique, which is suitable for the screening of congenital hyperarnm nerrii in the new born, the measurement of ammonia levels in the blood of small animals like rats and mice, and the assay of amino acids by determining the ammonia liberated after a specific ammonia forming enzymic reaction.…”

Section: Introductionmentioning

confidence: 99%

An Automated Microassay for Blood Ammonia

Imler¹,

Frick²,

Schlienger³

et al. 1979

Clinical Chemistry and Laboratory Medicine

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A microassay for blood ammonia has been developed. After dilution, blood is dialyzed by a continuous flow procedure, and the ammonium ions in the dialysate are assayed colorimetrically by the hypochlorite-phenol Berthelot reaction. Concentrations from 1 to 400 μπιοΐ/l NH^ can be measured in a 50 μΐ whole blood sample. Using slight modifications, concentrations up to 800 μπιοΐ/ΐ NHj can be determined. The precision, accuracy, sensitivity, and specificity of the method have been studied. In man, the usual values (mean ± 2 SD) found are 27.4 ± 10.2 μτηοΐ/ΐ NH^ in arterial blood, 20.9 ± 9.8 μτηοΐ/ΐ in venous blood. The usual values in rats and mice are very close to those given for man. Blutammoniak-Bestimmung mit einer automatischen MikromethodeZusammenfassung: Zur Bestimmung des Blutammoniaks wurde eine Mikromethode entwickelt. Das Blut wird nach Verd nnung kontinuierlich flie end dialysiert. Die Ammoniumionen werden im Dialysat kolorimetrisch mittels der Hypochlorit-Phenol Reaktion von Berthelot bestimmt. Ein Gehalt von l bis 400 μπιοΐ/ΐ NHj kann in 50 μΐ Vollblut bestimmt werden. Geringe methodologische Ab nderungen erlauben es, Konzentrationen bis zu 800 μπιοΐ/ΐ NHj zu messen. Pr zision, Genauigkeit, Empfindlichkeit und Spezifizit t der Methode werden untersucht. Beim Menschen sind mit dieser Methode die blichen Befunde (Mittelwert ± 2 SD) 27,4 ± 10,2 μπιοΐ/ΐ NHj im arteriellen Blut und 20,9 ± 9,8 μπιοΙ/1 im ven sen Blut zu erheben. Bei Ratten und M usen finden sich hnliche Werte.

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“…Arterial ammonaemia was measured using a method of automatic dialysis (Imler et al 1972); mean values (± 2 sd) were 50 ± 20 µg NH4 + /IOO ml lor the controls.…”

Section: Methodsmentioning

confidence: 99%

Possible Role of Hyperammonaemia and/or of Portosystemic Shunts on the Variability of the TSH Response to TRH in Cirrhotic Patients

Schlienger

Hasselmann

Imler

1978

Acta Endocrinologica

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Serum concentrations of thyroid hormones (T3, T4) and the TSH response to TRH administered iv were measured by radioimmunoassay in 21 patients with advanced cirrhosis and compared to 20 control patients without liver disease (group A). While the mean T4 values (8.6\m=+-\0.3\g=m\g/100ml) were similar for the two groups, the mean T3 values were significantly lower in patients with liver disease (123 \m=+-\12 vs. 156 \m=+-\10 ng/100 ml). The mean baseline TSH levels and the magnitude of the peak were normal but very scattered in these patients. The TSH response to TRH appeared independant of nutritional status, T4 and T3, anaemia, hypoalbuminaemia, transaminasaemia and bilirubinaemia. The TSH release after TRH injection seemed however to be markedly elevated in cirrhotic patients with hyperammonaemia. Therefore, patients with liver disease were separated into two groups according to the absence (group B; n = 11) or the presence (group C; n = 10) of hyperammonaemia. Mean T4 values and the free thyroxine index were lower in group C (7.2 \ m=+-\0.6 vs. 9 \ m=+-\0.6 \g=m\g/100 ml and 1.87 \ m=+-\ 0.16 vs. 2.49 \ m=+-\ 0.15) but mean T3 and basal TSH values did not differ in group B and C. The TSH response was slightly dispersed in B and lower than that observed in A or in C (P < 0.01). A hyperresponsiveness in 4 patients and a hyperresponsiveness in 2 other patients was noted in group C without any correlation with the basal TSH value or T3 or T Since hyperammonaemia has been considered as a biological parameter of hepatic encephalopathy, it is suggested that the THS release which is neuraminergic controlled may be altered by this situation resulting in a cerebral aminergic mediators depletion.

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Dosage de l'ammoniemie en discontinu et en continu par une technique de dialyse automatique

Cited by 34 publications

References 4 publications

Diabetogenic effect and inhibition of insulin secretion induced in normal rats by ammonium infusions

Diabetogenic effect and inhibition of insulin secretion induced in normal rats by ammonium infusions

An Automated Microassay for Blood Ammonia

Possible Role of Hyperammonaemia and/or of Portosystemic Shunts on the Variability of the TSH Response to TRH in Cirrhotic Patients

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