Successful management of hyperammonemia with hemodialysis on day 2 during 5-fluorouracil treatment in a patient with gastric cancer: a case report with 5-fluorouracil metabolite analyses

Purpose

Hyperammonemia is an important adverse event associated with 5-fluorouracil (5FU) from 5FU metabolite accumulation. We present a case of an advanced gastric cancer patient with chronic renal failure, who was treated with 5FU/leucovorin (LV) infusion chemotherapy (2-h infusion of LV and 5FU bolus followed by 46-h 5FU continuous infusion on day 1; repeated every 2 weeks) and developed hyperammonemia, with the aim of exploring an appropriate hemodialysis (HD) schedule to resolve its symptoms.

Methods

The blood concentrations of 5FU and its metabolites, α-fluoro-β-alanine (FBAL), and monofluoroacetate (FA) of a patient who had hyperammonemia from seven courses of palliative 5FU/LV therapy for gastric cancer were measured by liquid chromatography–mass spectrometry.

Results

On the third day of the first cycle, the patient presented with symptomatic hyperammonemia relieved by emergency HD. Thereafter, the 5FU dose was reduced; however, in cycles 2–4, the patient developed symptomatic hyperammonemia and underwent HD on day 3 for hyperammonemia management. In cycles 5–7, the timing of scheduled HD administration was changed from day 3 to day 2, preventing symptomatic hyperammonemia. The maximum ammonia and 5FU metabolite levels were significantly lower in cycles 5–7 than in cycles 2–4 (NH3 75 ± 38 vs 303 ± 119 μg/dL, FBAL 13.7 ± 2.5 vs 19.7 ± 2.0 μg/mL, FA 204.0 ± 91.6 vs 395.9 ± 12.6 ng/mL, mean ± standard deviation, all p < 0.05). After seven cycles, partial response was confirmed.

Conclusion

HD on day 2 instead of 3 may prevent hyperammonemia in 5FU/LV therapy.

Electronic supplementary material

The online version of this article (10.1007/s00280-020-04158-1) contains supplementary material, which is available to authorized users.

Quantitative analysis of monofluoroacetate in biological samples by high-performance liquid chromatography using fluorescence labeling with 9-chloromethylanthracene

A rapid and sensitive RP-HPLC method with fluorescence detection has been developed for the quantitative analysis of trace amounts of monofluoroacetate (MFA) in biological samples as serum, food and meat. 9-Chloromethylanthracene (9-CMA) is used as the fluorescence labeling reagent. Samples were extracted and reacted with 9-chloromethylanthracene together with tetrabutylammonium bromide as catalyst at 80 degrees C for 50 min to give a new fluorescent derivative as 9-methyleneanthracene monofluoroacetate (MA-MFA). The resulting MA-MFA was characterized with IR, (1)H NMR, (13)C NMR and MS. Chromatography separation is performed on an Agilent Hypersil ODS column with a fluorescent detector employed with the excitation and emission wavelengths as 256 nm and 412 nm, respectively. Optimal conditions for derivatization, fluorescence detection and chromatographic separation have been established. The novel method yields a good linear relationship when the MFA concentration in serum within 1 and 250 ng/mL (r=0.9988). The detection limit (signal-to-noise ratio=3 with 2 microL injected) was 0.25 ng/mL. The practical applicability of this method was demonstrated by quantitative determination of MFA-Na in a blood sample from a person who had ingested the poison.

[Determination of sodium monofluoroacetate in human blood and food samples by ion chromatography]

A method was developed for the determination of sodium monofluoroacetate in human blood by ion chromatography. The analysis was performed on a Dionex Ion Pac AS11 column (250 mm x 4 mm i.d.) with an AG11 guard column (50 mm x 4 mm i.d.). A conductivity detector, an SRS suppressor and a 25 microL sample loop were used. The eluent was 2.0 mmol/L Na2B4O7 with a flow rate of 1.0 mL/min. A blood sample of 0.2 mL was pipetted into a test tube followed by adding 1.0 mL of pure water. And then acetonitrile was used to dilute it to 3.0 mL. After the protein was settled down from the blood sample, the supernatant layer was filtered through a 0.45 microm filter before injected into the ion chromatographic system. Good linear relationship between the peak area and the concentration of sodium monofluoroacetate was found with correlation coefficient (r2) of 0.9978 within the range from 0.10 to 10.0 mg/L. The detection limit for blood was 2.5 mg/L. This method also can be used for the determination of sodium monofluoroacetate in food samples.

Headspace solid-phase microextraction with 1-pyrenyldiazomethane on-fibre derivatisation for analysis of fluoroacetic acid in biological samples

A new and in part automated headspace solid-phase microextraction method for quantitative determination of the highly toxic rodenticide fluoroacetic acid (FAA) in serum and other biological samples has been developed. FAA and deuterated acetic acid (internal standard) were extracted from acidified samples by a StableFlex divinylbenzene-Carboxen on polydimethylsiloxane fibre. The acids were derivatised on the fibre in-situ with 1-pyrenyldiazomethane and detected using gas chromatography-mass spectrometry with electron impact ionisation and selected ion monitoring. The calibration curve for FAA in serum was linear over the range from 0.02 to 5 microg/ml, with limits of detection and quantification of 0.02 and 0.07 microg/ml, respectively. The method was also tested with spiked whole blood, urine, stomach contents and kidney samples. It was sufficiently reliable, reproducible and sensitive for use in routine forensic toxicology applications.

Sorption of fluoroacetate (compound 1080) by Colestipol, activated charcoal and anion-exchange in resins in vitro and gastrointestinal decontamination in rats

The sorption of sodium fluoroacetate (FA) by activated charcoal (AC) and 5 anion exchange resins (AERs) was tested in 2 simulated gastrointestinal (GI) fluids. Each sorbent was incubated with FA in a shaker-water-bath at 37 C for 24 h. Supernatant was removed and filtered, and the concentration of FA was determined by gas chromatographic detection of the dichloroaniline derivative. Under simulated gastric conditions (0.1 M HCl at approximately pH 1.5), the sorbents removed the following proportions of FA from solution: Carbosorb AC, 87 +/- 2%; cholestyramine, 28 +/- 7%; colestipol, 96 +/- 0%; Amberlite IRA-96, 70 +/- 2%; DEAE-Sephadex, 7 +/- 4%; Chitosan, 66 +/- 2%. Under simulated intestinal conditions (0.05 M sodium phosphate at approximately pH 7.4), binding was as follows: Carbosorb AC, 68 +/- 4%; cholestyramine, 53 +/- 5%; colestipol, 46 +/- 2%; AmberliteIRA-96, 10 +/- 20%; DEAE-Sephadex, 64 +/- 7%; Chitosan, 5 +/- 2%. All findings differed significantly from control, with the exception of Amberlite IRA-96 and Chitosan in phosphate buffer, and DEAE-Sephadex in HCI. In a second study, rats were given 5 mg FA/kg, and then gavaged with 2 g/kg Carbosorb AC, colestipol or bentonite. Over 4 h, the area under the curve of serum FA versus time (AUC) decreased by 39% in the rats treated with colestipol and 42% in those treated with bentonite. In contrast, Carbosorb AC did not affect the AUC,yet increased Tmax In another study, mortality was assessed 96 h after rats were orally dosed with 5 mg FA/kg followed by gavage with 2 g/kg Carbosorb AC, colestipol or water immediatey or 30 min after dosing. When the sorbents were given immediately, mortality was the same as control (75%). Surprisingiy, the 30-min delay resulted in lower mortality in colestipol-treated rats, (approximately 38%) compared to 100% in the group treated with Carbosorb AC. Before any recommendation can be made regarding the use of colestipol as a GI decontaminant, the latter findings require confirmation in an intensive care setting. The potential for synergistic effects with 2 or more sorbents also warrant investigating.

Persistence of sodium monofluoroacetate in livestock animals and risk to humans

1. Sodium monofluoroacetate (1080), a vertebrate pesticide widely used in New Zealand, was administered orally to sheep and goats at a dose level of 0.1 mg kg-1 body weight to assess risk to humans of secondary poisoning from meat. Blood, muscle, liver, and kidney were analysed for 1080 residues. 2. The plasma elimination half-life was 10.8 h in sheep and 5.4 h in goats. Concentrations of 1080 in muscle (0.042 microgram g-1), kidney (0.057 microgram g-1), and liver (0.021 microgram g-1) were substantially lower than those in plasma (0.098 microgram ml-1) at 2.5 h after dosing. 3. Only traces of 1080 (< 0.002 to 0.008 microgram g-1) were found in sheep tissues after 96 hours. 4. Livestock are normally excluded from areas where 1080 is being used for pest control, reducing the risk of secondary poisoning. Even with accidental exposure to a sublethal dose 1080 would not persist in tissues for more than a few days because it is cleared rapidly from the body. Therefore the occurrence of 1080 in meat intended for human consumption is highly unlikely.

Determination of membrane potential and cell volume by 19F NMR using trifluoroacetate and trifluoroacetamide probes

The distribution of ionic species between intra- and extracellular compartments forms one basis for the determination of cell membrane potential. It is shown that fluorine-19 NMR studies of erythrocytes in the presence of trifluoroacetate, a stable, relatively nontoxic anion with pK = -0.3, provide a sensitive probe of membrane potential. Since such measurements are based on ion concentrations, the parallel use of the neutral analogue trifluoroacetamide to provide information on intra/extracellular volume ratios was also explored. In both cases, separate 19F resonances corresponding to intra- and extracellular ions were observed, with the intracellular resonance shifted downfield by approximately 0.2 ppm and the intracellular peak typically somewhat broader than the extracellular resonance. Studies with the band 3 anion-exchange inhibitor 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) indicate that both transmembrane diffusion and flux involving the band 3 anion exchanger contribute to the observed transport of the trifluoroacetate anion. Intra/extracellular volume ratios determined on the basis of trifluoroacetamide intensity ratios were in good agreement with determinations based on measured hematocrits. On the basis of the high sensitivity of 19F NMR and the capability of monitoring volume changes simultaneously, the time resolution for these measurements can approach the lifetime of intracellular trifluoroacetate ions and hence be limited by the trifluoroacetate flux rate.

Inorganic and organic fluoride concentrations in tissues after the oral administration of sodium monofluoroacetate (Compound 1080) to rats

Male rats were used to study the inorganic (ionic) and organic fluoride concentrations in plasma, liver, kidneys and stomach content after oral doses of 0, 2.2, 3.5, 4.0, 5.0 and 7.0 mg sodium monofluoroacetate (SMFA, Compound 1080)/kg body weight. Tissue and plasma ionic fluoride concentrations were observed to be higher in all rats given SMFA as compared to rats in the control group. This observation suggests in vivo defluorination of SMFA. Homogenates of liver obtained from SMFA poisoned rats showed significant increases in ionic fluoride concentration during a 6-day storage period at +4 degrees C, with the total fluoride concentration (ionic and organic) remaining constant. The average percentages of distribution of SMFA (organic fluoride) in plasma, liver, and kidneys were 7.05, 5.07 and 1.68, respectively. Plasma and tissue SMFA concentrations were generally lower than the corresponding stomach fluid SMFA concentrations for all dosage groups. Lethal concentration of SMFA in the liquid stomach content was in the range 84.9--189 micrograms/ml, corresponding to total (ionic and organic) fluoride concentrations in the range of 16.1--36 micrograms/ml.