Analysis of mucin as raw material and in a saliva substitute by isotachophoresis.

An isotachophoretic method is presented for the analysis of the glycoprotein mucin as raw material. The assay is also used for the mucin assay in the saliva substitute Saliva Orthana.

Plasma spermidine and putrescine as markers of cancer management.

The hypothesis was tested that dying tumor cells release spermidine and putrescine into the bloodstream. Therefore, a rhabdomyosarcoma was implanted in rats, irradiated and its growth and subsequent reduction compared with spermidine and putrescine plasma concentrations of the venous effluent from the tumor side and contralateral side. In the experimental set-up used the hypothesis could not be verified. It appeared that irradiation only, implantation and growth of a tumor only and an irradiated tumor, all caused elevated spermidine and putrescine concentrations in the effluent of both sides in approximately the same order of magnitude, compared to untreated controls.

The elimination of spermidine from plasma in rats.

Infused spermidine in rats with bypassed livers was eliminated very slowly, whereas endogenous spermidine in saline-infused controls with bypassed livers increased. In the same animals endogenous putrescine plasma levels did not differ significantly between spermidine- or saline-infused animals, whereas endogenous cadaverine levels increased during spermidine infusion and decreased afterwards. It is concluded that the liver is the most important site for plasma spermidine elimination.

pH modulates cisplatin toxicity.

Cisplatin in normal saline of pH 2.5 caused haemolysis of rat erythrocytes, whereas cisplatin in normal saline of pH 3.5 did not. Even a difference of 0.2 pH units appeared to be of significant importance: haemolysis of rat erythrocytes was observed with cisplatin in saline of pH 3.0 but not with cisplatin in saline of pH 3.2. The LD in mice was 15.4 mg/kg for cisplatin in saline of pH 2.5 versus 24.0 mg/kg for cisplatin in saline of pH 3.5. Experiments with cisplatin should include careful control of pH.

The influence of anaesthesia on plasma spermidine concentration and renal excretion in rats.

Anaesthesia with ether or a mixture of fentanyl and fluanisone diminished the clearance of infused spermidine from plasma in WAG/Rij rats considerably. The renal excretion of infused spermidine in unanaesthetized animals was only very small. The diminished plasma clearance of infused spermidine in anaesthetized animals therefore cannot be explained by loss of renal excretion.

Does determination of polyamines in body fluids require heating with hydrochloric acid?

In this study it is shown that hydrolysis of plasma and urine by heating with concentrated hydrochloric acid does not increase the recovery of spermidine from these body fluids.

The fate of infused spermidine in the plasma of rats.

An elevation of the plasma spermidine concentration might indicate whether administration of a cytostatic drug harms tumour cells. Such elevations, however, are only small. By infusing various amounts of spermidine into the circulation of rats, spermidine plasma elevations were evoked artificially. During 2.5 h infusion and 1.5 h after infusion spermidine plasma concentrations were measured. It appeared that total amounts of 0.031 and 0.4 mg did not give an appreciable elevation of plasma spermidine concentrations above basic levels. Infusion of 1.0 mg gave rise to an elevation but already showed a trend towards normal levels during the infusion. There is evidence for a first-pass lung effect for spermidine. Blocking of monoamine and diamine oxidase enzymes resulted in a further elevation of spermidine concentrations above basic levels. Which of the two enzymes is the more important for spermidine catabolism could not be determined.

Determination of polyamines in plasma by capillary gas chromatography and some applications.

An analytical method is presented making it possible to measure spermidine concentration in 0.2 ml plasma. After derivatization and extraction following an existing procedure, spermidine was measured by gas chromatography using nitrogen-phosphorus detection. Mounting capillary columns decreased the limit of determination to 0.05 nanomole/ml for routine determination. Some applications of the method in animal model systems are shown. The method is also applicable to other polyamines.

Determination of plasma concentrations of underivatized cyclophosphamide by capillary gas chromatography.

A sensitive method for the clinical determination of cyclophosphamide in 0.2 ml plasma by capillary gas chromatography with nitrogen-phosphorus detection is described. A detection limit of 50 nl/ml is readily obtainable, which is sufficiently low to measure the cyclophosphamide concentrations occurring in clinical practice. The selection of internal standards and the use of the nitrogen-phosphorus detection system is discussed, as well as eventualities for determination of cyclophosphamide metabolites.

Analysis of methotrexate by isotachophoresis.

This paper shows that the anion of methotrexate (MTX) can be readily separated and quantified by isotachophoresis. An extraction method for MTX is also presented, appropriate for isotachophoretic studies. The extraction of MTX is based on the complexation and precipitation of MTX with metal ions. The recovery of MTZ from plasma is about 75%.

Treatment of theophylline intoxication: a model study utilizing peritoneal dialysis.

This study shows that peritoneal dialysis of theophylline-intoxicated rats results in withdrawal of approximately 27% of the administered dose of theophylline in 4 hr. Clinical consequences of this experience are considered.