We adapted a high-performance liquid chromatographic method with electrochemical detection (Clin Chim Acta 1984;139:1-12) to the determination of platelet serotonin. We used this method to determine platelet serotonin reference values in a healthy population, measuring platelet serotonin concentration in the following subjects: 31 newborns (16 girls, 15 boys); 41 children (11 girls, 30 boys), ages 20 months to 15 years; 56 adults (26 women, 30 men), ages 20 to 58 years; and 20 elderly subjects (16 women, four men), ages 65 to 94 years. There was no significant difference in platelet serotonin concentration between sexes in each age group. However, significant changes (P less than 0.001) were observed between the newborns (mean +/- SD: 1.67 +/- 0.74 nmol/10(9) platelets) and the children (4.09 +/- 1.04) or the adults (3.81 +/- 0.87). Moreover, the platelet serotonin concentration in the elderly subjects (2.57 +/- 1.12) was significantly (P less than 0.001) lower than in the adults and children and significantly higher (P less than 0.01) than in the newborns. Such age-related differences must be taken into consideration when data from neurological or psychiatric patients and control subjects are compared.

No abstract

The aim of this study was to determine whether oral supplementation with EPA/DHA (10.5 and 5.1% of fat, respectively) could improve the outcome of pulmonary P. aeruginosa infection in cftr(-/-) mice compared with wild-type (Wt) mice similarly treated. Because gender could influence the susceptibility of cftr-deficient mice, results were analyzed by gender. Wt and (-/-) mice were randomized for 6 wk to consume a control or EPA/DHA diet, infected with endotracheal injection of 5 × 10(7) CFU/mouse of P. aeruginosa, and killed 24 h later. Cftr(-/-) mice were more susceptible to infection than were Wt mice; (-/-) males had more neutrophils (P < 0.01) and a higher keratinocyte-derived chemokine (KC) level (P < 0.05), and (-/-) females had greater lung injury and mortality (P < 0.05). Female (-/-) mice were more susceptible than (-/-) males with a higher mortality and lung injury (P < 0.05). The EPA/DHA diet reduced neutrophil numbers and KC and IL-6 levels (P < 0.05) in (-/-) males and reduced mortality rate (P < 0.001), lung permeability, and IL-6 level (P < 0.05) in (-/-) females compared with (-/-) mice fed the control diet. These results were associated with a reduction in the pulmonary bacterial load (P < 0.05), an increase in the EPA/DHA concentration in cell membranes of (-/-) males and females (P < 0.01), and an increased weight gain only in males compared with (-/-) mice fed the control diet (P < 0.01). In conclusion, EPA/DHA improves the host resistance of (-/-) mice, although the beneficial effect differed in males and females.

No abstract

The determination of platelet serotonin (5-HT) and plasma tryptophan concentrations is useful in the diagnosis, investigation of etiologies, and treatment of psychiatric disorders. To determine the usual circadian variations in platelet 5-HT and free and total tryptophan concentrations, we measured these variables during 24 h at 1-h intervals and every 30 min from 2000 to 0800 in seven clinically healthy young men with an HPLC method. No common circadian rhythm for platelet serotonin concentrations was observed in our subjects; however, there was a distinct rhythm for both free and total plasma tryptophan: Concentrations were maximal in the afternoon and minimal during the night.