Liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry for the analysis of sulfaquinoxaline byproducts formed in water upon solar light irradiation.

RATIONALE: Sulfonamides such as sulfaquinoxaline (SQX) are among the most important antibiotic families due to their extensive use in veterinary medicine. The prediction of their fate under solar irradiation through the identification of the generated metabolites is required. However, unambiguous structural characterizations often remain a challenge particularly when several isomers could match with the same MS(2) data. METHODS: Liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry (LC/ESI-Q-TOFMS) in the positive ion mode, leading to the formation of the protonated forms of the studied compounds, [M + H(+)] ions, was employed. Collision-induced dissociation tandem mass spectrometry (CID-MS/MS) of the protonated molecules was carried out, and the effect of the collision energy as well as the elemental compositions of the product ions were used to propose chemical structures. Validation of the hypothesized structures was performed by the calculation of key fragmentation pathway energies using density functional theory (DFT) calculations (B3LYP/6-31 G (d,p)). RESULTS: The photoproducts were identified as 2-aminoquinoxaline, SQX isomers, 2-(N-parabenzoquinoneimine)quinoxaline and isomers resulting from SO(2) extrusion. The direct fragmentations of [SQX + H](+) and its protonated isomers mostly occurred through the loss of 2-aminoquinoxaline and/or the 4-sulfoaniline radical ion, while their rearrangements involved the migration of H and/or O atoms. For the desulfonated byproducts in their protonated forms, the main neutral losses were of the quinoxaline radical, aminoquinoxaline and NH(3). The fragmentation of the protonated 2-aminoquinoxaline mainly involved the elimination of NH(3) and HCN. CONCLUSIONS: LC/ESI-Q-TOFMS and DFT calculations have been shown to be useful and complementary methods for the identification of unknown isomeric compounds and the elucidation of fragmentation patterns, in the case of the sulfaquinoxaline veterinary antibiotic.

[Perceptions of benign prostatic hyperplasia according to the perspective of patients and general practitioners - the Trophée study]. / Perceptions de l'hypertrophie bénigne de la prostate par le patient et le médecin généraliste - étude Trophée.

OBJECTIVE: To compare the perception of benign prostatic hypertrophy (BPH) between patients and general practitioners (GPs) in terms of severity and evolution of symptoms and medication adherence. METHODOLOGY: A cross-sectional observational study was performed in France in a sample of GPs who included patients for whom a BPH treatment was prescribed. Data were collected on patient and GP characteristics, diagnosis, BPH management, severity and evolution of symptoms and medication adherence. RESULTS: One thousand and ninety-eight patients were recruited by 247 GPs. In 87.4% of cases, diagnosis was performed by GPs. Among them, 82.7% of patients were treated by monotherapy. The choice of a treatment was mainly based on treatment efficacy and the patient's opinion was taken into account by 5% of GPs. The patient's evaluation of symptoms severity was consistent with the GP's in 53.9% of cases. A worsening of symptoms was reported significantly more frequently by patients (18.5%) than by GPs (8.8%). Among 94 patients who reported poor adherence, GPs estimated that the level of medication adherence was good for 72 of these (77%). CONCLUSION: There was discordance between the evaluation made by GPs and by patients on the perception of BPH symptoms and medication adherence. The patient's opinion was rarely taken into account in the therapeutic decision, reflecting a lack of shared medical decision-making, which would be helpful for the physician in order to optimize BPH management.

Circadian variation of postprandial lipemia.

The goal of the present study was to assess the influence of mealtime on postprandial lipemia. Thirteen healthy subject aged 19-32 y were given the same meal at night (0100) or during the day (1300) in random order: the meal contained 40% of estimated daily energy expenditure. Blood samples were drawn at baseline and hourly for 8 h after the meal. Serum total cholesterol, very-low-density-lipoprotein cholesterol (VLDL-C), low-density-lipoprotein cholesterol (LDL-C), high-density-lipoprotein cholesterol (HDL-C), triacylglycerols, VLDL-triacylglycerols, apolipoprotein (apo) A-I, and apo B were measured at each time point. In a subgroup of seven subjects a control fasting reference line was measured according to the same nocturnal and diurnal time schedule. The mean postprandial concentrations of triacylglycerol (P < 0.001), VLDL-triacylglycerol (P < 0.001), and VLDL-C (P < 0.001) were higher at night than during the day. In contrast, mean cholesterol (P < 0.01), LDL-C (P < 0.01), HDL-C (P < 0.001), apo A-I (P < 0.001), and apo B (P < 0.001) concentrations were lower after the night meal than after the day meal. The magnitude of the postprandial response was estimated by the area between the fasting and postprandial curves. The triacylglycerol and VLDL-triacylglycerol responses were not significantly different between night and day. The VLDL-C (P < 0.01) response was greater and LDL-C (P < 0.0001) and HDL-C (P < 0.01) responses were lower at night than during the day. These results indicate that circadian factors specifically affect serum cholesterol transport. Apo B (P < 0.01) and apo A-I (P < 0.01) responses followed LDL-C and HDL-C changes during the day but were dissociated from lipoprotein responses at night, suggesting that circadian apolipoprotein regulation is dissociated from that of serum lipids. The results of the present study indicate that postprandial lipid, lipoprotein, and apolipoprotein concentrations are affected by circadian factors.

Influence of mental stress and circadian cycle on postprandial lipemia.

BACKGROUND: Mental stress produces alterations in serum lipids and lipoproteins. OBJECTIVE: The objective was to assess the effect of mental stress during the day and night on postprandial lipoproteins. DESIGN: Fourteen healthy subjects aged 26.6 +/- 5.0 y were given randomly the same meal either at night (0100) or during the day (1300), with or without (control session) a mental stress challenge. The meal contained 40% of estimated daily energy needs. The mental task was performed on a computer and consisted of a task of choice reaction. Blood samples were drawn at baseline and hourly for 7 h after the meal. RESULTS: Urinary epinephrine concentrations were higher (P < 0.012) during the mental task than during the control sessions. Repeated-measures analysis of variance showed that mean postprandial triacylglycerol concentrations were significantly higher (P < 0.02) and total cholesterol (P < 0.0001) and HDL-cholesterol concentrations were significantly lower (P < 0.0001) at night than during the day. The mean postprandial VLDL-triacylglycerol concentration was significantly higher (P < 0.04) during the mental task than during the control sessions. Similarly, the VLDL-cholesterol response, calculated as the area under the postprandial curve, was significantly greater (P < 0.02) during the mental task than during the control sessions. There was no interaction between mental stress and nyctohemeral cycle on postprandial lipoprotein responses, suggesting that both indexes act independently on postprandial lipid metabolism. CONCLUSIONS: Mental stress is associated with increased concentrations of postprandial triacylglycerol-rich lipoprotein fractions. Therefore, postprandial hyperlipidemia is one possible mechanism contributing to the higher risk of ischemic heart disease in stressed people.

Time structure of behavioral patterns related to feed pecking in chicks.

Nonrandom time patterns of pecking acts by 16 chicks were detected using the software Theme during three videotaped pecking sessions (M, C, and A). At 15 days of age pecking session, M (mash) was recorded when chicks ate a mash diet. Pecking session C (change) at 16 or 17 days of age was recorded immediately after the change of the diet to pellets presented either as regular cylinders (P) to eight chicks, or as semiovoid (Po) to eight other chicks. Pecking session A (adapted) was recorded 5 or 6 days after adaptation to P and Po. Successful (consumatory) pecks were 72%, 52%, and 61% of all pecks for sessions M, C, and A, respectively. The head of the chicks remained in a steady position between two consecutive pecks for a longer period during C (65% of the time) than M and A (54%). During C, the pecking rate was less for P (0.54 pecks/s) than for Po (0.79 pecks/s). Two consistent time patterns involving four acts frequently observed were: head rotation (or exploratory peck)-->head in steady position-->consumatory peck-->head in steady position with jaw movements. Time intervals within a pattern were stable throughout sessions. However, the proportion of synchronized (included in a pattern) vs. nonsynchronized (not included in a pattern) acts decreased immediately after the change of feed form (session C). These results suggest that pecking at feed is composed of two distinct sets of acts: consistently organized patterns little affected by the form of the pecked particles and nonsynchronized acts that may be involved in sensory information.

Short term response of circulating leptin to feeding and fasting in man: influence of circadian cycle.

OBJECTIVE: To investigate whether acute feeding induces changes in circulating leptin levels in humans and whether these changes vary according to nycthemeral cycle. METHODS: First experiment. Eighteen male subjects were given a fatty meal at 08.00 h. Blood sampling was performed for 10 h following this meal. Second experiment. Thirteen male subjects were given either a mixed meal or remained fasting either at night (starting at 01.00 h) or during the day (starting at 13.00 h). Blood samples were drawn every hour for a period of 8 h. RESULTS: First experiment. Serum leptin levels increased progressively from a mean (s.d.) baseline of 3.8 +/- 2.2 ng/ml to a value of 4.5 +/- 2.7 ng/ml (P < 0.01) 8 h after the fatty meal. Second experiment. During the day, serum leptin levels increased progressively from 2.65 +/- 1.7 to 3.34 +/- 2.2 ng/ml (P < 0.001) 6 h after the test-meal and decreased from 2.68 +/- 1.5 to 1.9 +/- 1.1 ng/ml (P < 0.001) 8 h after the beginning of the fasting experiment. Similar results were obtained at night. No statistically significant differences in leptin levels were observed between day and night sessions in response to feeding (mean area under the curve: 3.0 +/- 4.1 vs 4.1 +/- 4.1 ng/ml) and fasting (-2.9 +/- 2.2 vs -1.5 +/- 2.2 ng/ml). CONCLUSION: In two independent experiments, human serum leptin levels increase following food intake. This response is not influenced by nycthemeral cycle.