Pterins as sensors of response to the application of Fe3+ -dextran in piglets

Determination of Urinary Pterins by Capillary Electrophoresis Coupled with LED-Induced Fluorescence Detector

Urinary pterins have been found as potential biomarkers in many pathophysiological conditions including inflammation, viral infections, and cancer. However, pterins determination in biological samples is difficult due to their degradation under exposure to air, light, and heat. Besides, they occur at shallow concentration levels, and thus, standard UV detectors cannot be used without additional sample preconcentration. On the other hand, ultra-sensitive laser-induced fluorescence (LIF) detection can be used since pterins exhibit native fluorescence. The main factor that limits an everyday use of LIF detectors is its high price. Here, an alternative detector, i.e., light-emitted diode induced fluorescence (LEDIF) detector, was evaluated for the determination of pterins in urine samples after capillary electrophoresis (CE) separation. An optimized method was validated in terms of linearity range, limit of detection (LOD), limit of quantification (LOQ), intra- and interday precision and accuracy, sample stability in the autosampler, and sample stability during the freezing/thawing cycle. The obtained LOD (0.1 µM) and LOQ (0.3 µM) values were three-order of magnitude lower compared to UV detector, and two orders of magnitude higher compared to previously reported house-built LIF detector. The applicability of the validated method was demonstrated in the analysis of urine samples from healthy individuals and cancer patients.

Simultaneous determination of twelve polar pteridines including dihydro- and tetrahydropteridine in human urine by hydrophilic interaction liquid chromatography with tandem mass spectrometry

Pteridines and their derivatives are important cofactors in the process of cell metabolism, and the level of urinary excretion of these compounds is considered as an important clinical criterion. In this work, a new separation method involving hydrophilic interaction chromatography (HILIC) with tandem mass spectrometric detection has been developed for the simultaneous analysis of 12 pteridines including oxidized, di- and tetrahydroforms, namely neopterin, 7,8-dihydroneopterin, biopterin, 7,8-dihydrobiopterin, 5,6,7,8-tetrahydrobiopterin, dimethylpterin, dimethyltetrahydropterin, pterin, isoxanthopterin, xanthopterin, sepiapterin and pterin-6-carboxylic acid, in human urine without oxidative pretreatments. The stabilizing agent (dithiothreitol) at various concentrations and the stability of oxidized, di- and tetrahydroforms during the sample's short-term storage and processing and of the extracts were tested. In the developed method, 12 pteridines were chromatographically separated on an ZIC-HILIC column by gradient elution, and the run time was 20 min. Matrix effect was evaluated and several dilutions of urine were tested in order to study the evolution of signal suppression. Spiked recovery studies demonstrated that the technique was both accurate (83.1-116.7%) and precise (RSD 1.4-15.6%). Finally, several clinical urine specimens without oxidative pretreatments were examined with the new technique and compared with previous reports.

Breaking the succession rule: the costs and benefits of an alpha-status take-over by an immigrant rhesus macaque on Cayo Santiago

Explaining intraspecific variation in reproductive tactics hinges on measuring associated costs and benefits. Yet, this is difficult if alternative (purportedly less optimal) tactics remain unobserved. We describe a rare alpha-position take-over by an immigrant male rhesus macaque in a population where males typically gain rank via succession. Unusually, male aggressiveness after the take-over correlated with rank and mating success. The new alpha achieved the highest mating and reproductive success. Nevertheless, he sired only 4 infants due to high extra-group paternity (59.3%). The costs of his immigration tactic were high: after the mating season ended, unable to deter coalitionary attacks by resident males, he was overthrown. The following year he had the highest relative annual weight loss and levels of immune activation among males in the group. Succession-based rank-acquisition in large, provisioned groups of macaques thus appears to be actively maintained by resident males, who impose high costs on challengers.

Neopterin and biopterin as biomarkers of immune system activity associated with crating in broiler chickens

Neopterin and biopterin belong to a group of unconjugated pterin derivates. These biomolecules are present in many animal species and perform several functions. Pterin concentrations may provide additional information on the effect of stress on immune system activity. This study focused on an investigation of the effect of crating on plasma concentrations of neopterin and biopterin in broilers. The effects of 2 crating periods (2 and 4 h) were monitored in Hubbard broilers (n = 90) aged 42 d. After a given crating period, randomly selected chickens from each group were sampled immediately and the remaining chickens were sampled after 24 h. Plasma corticosterone increased (P < 0.001) immediately after 2 and 4 h crating, but no difference between the crated and the control noncrated broilers was found 24 h later. Immediately after crating, neopterin in 2- and 4-h broilers did not differ from the control, but 24 h later a decrease (P = 0.011) in plasma neopterin was found in 4-h broilers compared with the control. Simultaneously, 24 h after crating, neopterin levels in 2- and 4-h broilers decreased (P < 0.001) in comparison with the levels immediately after crating. Plasma biopterin was higher (P < 0.001) in 4-h broilers than in the control immediately after the crating. A time of sampling effect (P = 0.016) was found for the heterophil-to-lymphocyte ratio, with heterophil-to-lymphocyte ratio higher 24 h after crating in comparison with its level immediately after the crating. This study shows that crating may significantly affect the immune system of broiler chickens. This is corroborated by the increase in plasma biopterin concentrations in broilers immediately after crating and the decrease in plasma neopterin concentrations in broilers 24 h after crating. The correlations were found for widely used indicators of acute and chronic stress in birds [i.e., plasma corticosterone concentrations (biopterin) and the heterophil-to-lymphocyte ratio (neopterin), respectively].

Effect of prochloraz fungicide on neopterin and biopterin concentrations in blood plasma of common carp

Neopterin and biopterin are often used as markers of cell mediated immunity. The aim of this study was to evaluate the effect of prochloraz on neopterin and biopterin concentrations in blood plasma of common carp as possible indicators for monitoring perturbations of the immune system caused by xenobiotics like pesticides. Prochloraz is a widely used imidazole fungicide in horticulture and agriculture. A total of 60 juvenile common carp were divided into four groups of 15 fish and exposed to prochloraz at concentrations of 0, 50, 150 and 380 µg·l-1, respectively. The total length of exposure was 28 days. Neopterin and biopterin concentrations were determined by reverse phase high performance liquid chromatography with fluorescence detection. Our results indicated that concentrations of neopterin (25 ± 7.6 nmol·l-1) and biopterin (190 ± 29 nmol·l-1) in plasma of untreated common carp were comparable with those in mammals. Neopterin concentrations significantly (P< 0.01) increased after exposure to prochloraz in comparison to non-exposed fish, while biopterin concentrations were not influenced by exposure to prochloraz. This study contains new data on neopterin and biopterin concentrations in fish plasma and investigates neopterin and biopterin in their non-traditional role as markers of cell mediated immunity of fish associated with pesticide exposure.

Neopterin and biopterin as biomarkers of immune system activation associated with castration in piglets

Recent reports have shown that stressful situations may affect the production of unconjugated pterins (neopterin and biopterin). The aim of the study was to investigate the effect of castration on neopterin and biopterin plasma concentrations in piglets, using 2 groups of 12 piglets allocated to castrated and uncastrated (control) groups. Pterin concentrations were determined by HPLC with fluorescence detection. Blood samples were also analzyed for leukocyte profiles and plasma cortisol concentrations. A time × treatment interaction (P < 0.05) was detected for neopterin concentrations, such that neopterin was greater (P < 0.01) at 1 h after surgery in castrated piglets compared with precastration concentrations, and neopterin was greater (P = 0.05) in castrated than in control piglets at 1 h. Castration had no effect on biopterin concentration (P > 0.1). Time effects (P < 0.05) for neutrophil and lymphocyte concentrations and neutrophil-to-lymphocyte ratios were found. A time × treatment interaction (P < 0.01) was detected for plasma cortisol concentrations, such that cortisol was greater (P < 0.01) at 1 and 24 h after surgery in castrated piglets compared with precastration concentrations and was greater (P < 0.01) in castrated than in control piglets at 1 and 24 h. This study showed that castration activated the immune system of piglets as demonstrated by an increase in plasma neopterin concentrations.