Lifestyle and psychological factors related to irritable bowel syndrome in nursing and medical school students.

BACKGROUND: Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder comprising abdominal pain, abdominal discomfort, and disordered defecation. The prevalence of IBS is 10-15% in the general population. This study investigated the prevalence of IBS and the relationship between IBS and stress, lifestyle, and dietary habits among nursing and medical school students. METHODS: A blank self-administrated questionnaire was used to survey 2,639 students studying nursing or medicine. This questionnaire asked about IBS symptoms, lifestyle, dietary intake, life events, anxiety, and depression. The questionnaires were collected from 2,365 students (89.6%) and the responses of 1,768 students (74.8%) were analyzed. RESULTS: The prevalence of IBS was 35.5% as a whole, 25.2% in males and 41.5% in females. Significantly higher stress scores (anxiety and depression) and life events were found in the IBS group than in the non-IBS group. Sleep disorders and the time spent sitting were also higher in males with IBS. In the IBS group, females ate less fish, fruit, milk, and green-yellow vegetables, and more processed food products than the non-IBS group (p = 0.001, p = 0.002, p = 0.032, p = 0.037, p < 0.001). The rates of missed meals and irregular mealtimes were significantly higher in females in the IBS group (p = 0.001, p = 0.013). CONCLUSIONS: The prevalence of IBS was higher among nursing and medical students, and further interventional studies are needed to improve IBS symptoms.

Weak cation-exchange restricted-access material for on-line purification of basic drugs in plasma.

A methylcellulose-immobilized weak cation-exchange (MC-WCX) silica-based restricted-access material (RAM) was developed. The MC-WCX consists of an MC outer surface and 2-carboxyethyl phase internal surface, allowing for direct analysis of basic drugs in plasma. The retention properties of the MC-WCX were evaluated for sulpiride, quinidine, ranitidine, and desipramine. The MC-WCX retained model drugs by cation-exchange, and retained drugs were eluted with the mobile phase containing small amount of acids or salts compared with the MC strong cation-exchanger (MC-SCX). These results indicated the ease of use of the MC-WCX solid-phase extraction (SPE) column when coupled to a reversed-phase analytical column in column-switching high-performance liquid chromatography (HPLC), and various detection principals. Further direct analysis of model drugs in plasma using the MC-WCX SPE column in a column-switching HPLC system successfully performed with sufficient recovery. It is concluded that the MC-WCX is useful for the analysis of basic drugs in plasma.

Sensitive determination of aspirin and its metabolites in plasma by LC-UV using on-line solid-phase extraction with methylcellulose-immobilized anion-exchange restricted access media.

We describe a sensitive determination of aspirin (ASA) and its three metabolites (salicylic acid [SA], 2,3-dihydroxybenzoic acid [2,3-DHBA], and 2,5-dihydroxybenzoic acid [gentisic acid (GA)]) in rat plasma. Analysis was carried out by on-line solid-phase extraction (SPE) using a methylcellulose-immobilized-strong anion-exchanger (MC-SAX), followed by liquid chromatography (LC) coupled with UV detection. The lower limits of quantitation for ASA and SA were 60 ng/mL in 100 microL of plasma, respectively. This method was validated with respect to intra- and inter-day precision, accuracy, and linearity up to concentrations of 20,000 ng/mL for ASA, SA, 2,3-DHBA and gentisic acid, respectively. The method was successfully applied to an analysis of the pharmacokinetics of ASA and SA in rats.

The intestinal first-pass metabolism of substrates of CYP3A4 and P-glycoprotein-quantitative analysis based on information from the literature.

It is suggested that the bioavailability of CYP3A4 substrates might be low due to first-pass metabolism in the small intestine, and it is possible that P-glycoprotein (P-gp) may influence first-pass metabolism in a co-operative manner. We have collected information of the pharmacokinetics of CYP3A4 substrates to evaluate the fraction absorbed (Fa), intestinal availability (Fg) and hepatic availability (Fh) and have investigated the intestinal first-pass metabolism and the effect of P-gp on this. The pharmacokinetic data involved ten compounds metabolized by CYP3A4 in humans, with and without an inhibitor or inducer. FaFg, which is the product of Fa and Fg, and Fh were calculated using three liver blood flow rates (17.1, 21.4, 25.5 mL/min/kg) in consideration of variations in the liver flow rate. Co-administration with an inhibitor of CYP3A4 and treatment of an inducer of CYP3A4 caused an increase and decrease in the FaFg of CYP3A4 substrates, regardless of the liver blood flow, indicating that CYP3A4 substrates exhibit a first-pass effect in their metabolism. This holds true regardless of whether the compounds are P-gp substrates or not. No relationship was observed between FaFg and Fh, regardless of the hepatic blood flow rate and the P-gp substrates. The FaFg of both P-gp and non P-gp substrates decreased as the hepatic intrinsic clearance increased. FaFg was markedly reduced when the hepatic intrinsic clearance was more than 100 mL/min/kg. This in vivo intrinsic clearance corresponds to an in vitro intrinsic clearance of 78 muL/min/mg human hepatic microsomal protein, equivalent to a half-life of 8.9 min for the substrate in a commonly used metabolic stability test with human microsomes (1 mgMs protein/mL). This phenomenon was not observed in substrates of CYP isoforms other than CYP3A4. In conclusion, it is suggested that CYP3A4 substrates which have a hepatic intrinsic clearance of 100 mL/min/kg exhibit a low bioavailability due to intestinal first-pass metabolism, regardless of whether they are substrates of P-gp or not.