Glycemic Index and Insulinemic Index of Foods: An Interlaboratory Study Using the ISO 2010 Method.

An official method for determining food glycemic index (GI) was published by the Organization for International Standardization (ISO) in 2010, but its performance has not been assessed. Therefore, we aimed to determine the intra- and inter-laboratory variation of food GI values measured using the 2010 ISO method. Three laboratories (Australia, Canada and France) determined the GI and insulinemic-index (II) of six foods in groups of 13-15 participants using the 2010 ISO method and intra- and inter-laboratory Standard Deviations (SDs) were calculated. Overall mean food GIs varied from 47 to 86 (p < 0.0001) with no significant difference among labs (p = 0.57) and no food × laboratory interaction (p = 0.20). Within-laboratory SD was similar among foods (range, 17.8-22.5; p = 0.49) but varied among laboratories (range 17.5-23.1; p = 0.047). Between-laboratory SD of mean food GI values ranged from 1.6 to 6.7 (mean, 5.1). Mean glucose and insulin responses varied among foods (p < 0.001) with insulin (p = 0.0037), but not glucose (p = 0.054), varying significantly among labs. Mean II varied among foods (p < 0.001) but not among labs (p = 0.94). In conclusion, we found that using the 2010 ISO method, the mean between-laboratory SD of GI was 5.1. This suggests that the ISO method is sufficiently precise to distinguish a mean GI = 55 from a mean GI ≥ 70 with 97-99% probability.

Digestive Symptoms in Healthy People and Subjects With Irritable Bowel Syndrome: Validation of Symptom Frequency Questionnaire.

GOALS: The aim of this study was to validate the ability of symptom frequency questionnaire to differentiate between irritable bowel syndrome (IBS) patients and healthy subjects. BACKGROUND: A digestive symptom frequency questionnaire (DSFQ) was previously used in a food efficacy trial in a non-IBS population with mild gastrointestinal symptoms. STUDY: We compared 2 well-defined populations: 100 IBS patients fulfilling Rome III criteria (mean age 32 y; range, 18 to 59 y), and 100 sex-matched and age-matched healthy subjects. Frequency of individual digestive symptoms (abdominal pain/discomfort, bloating, flatulence, borborygmi) was assessed using a 5-point Likert scale (from none to everyday of the week) and the IBS severity with the IBS-SSS questionnaire. Health-Related Quality of life (HRQoL) was assessed with the Food and Benefits Assessment (FBA) and Functional Digestive Disorders Quality of Life (FDDQL) questionnaires. The digestive (dis)comfort dimension of these questionnaires was considered as the main dimension for HRQoL. RESULTS: The DSFQ discriminated IBS from healthy subjects with a significant difference (P<0.001) between groups (estimated mean difference=5.58; 95% CI, 4.91-6.28). On the basis of the ROC curve (AUC=0.9479), a cutoff value of 5 gives a sensitivity of 92% and a specificity of 84%, with a positive likelihood ratio of 5.75. Composite score of symptoms correlated strongly (P<0.0001) with digestive discomfort measured by FDDQL (-0.816), digestive comfort measured by FBA (-0.789), and the IBS-SSS score (0.762). CONCLUSIONS: Measurement of digestive symptom frequency by means of the DSFQ can differentiate IBS from healthy subjects, and shows a good correlation with other validated questionnaires (clinical trial #NCT01457378).

Low-frequency ultrasound sonophoresis to increase the efficiency of topical steroids: a pilot randomized study of humans.

Topical steroids are efficient in vasoconstriction potential, which is linked to their anti-inflammatory activity. Low-frequency ultrasound (US) applied on the skin (sonophoresis) may enhance the transdermal transport of various steroids. We aimed to assess, in a simple, blinded, randomized controlled pilot study, the clinical efficiency of sonophoresis in increasing vasoconstriction by enhancing the transdermal penetration of topical steroids in human skin. The study took place in the Clinical Investigation Center of the University Hospital of Tours and involved healthy volunteers. Three circular zones were delimited on each of the subjects' forearms: zone 1 (right and left) received topical steroids with 1-h occlusion, zone 2 with 2-h occlusion, and zone 3 with massage. Forearms were randomized to first undergo US, using a 36 kHz probe, delivered in a pulsed mode (2s on/5s off), during 5 min, with a US intensity of 2.72 W/cm(2), or no US. We used betamethasone 17-valerate in cream form as the topical steroid. The primary outcome was difference between forearms in skin color (increased whiteness reflecting the intensity of vasoconstriction) measured by 2 scores: values obtained with a chromameter (the higher the value, the whiter the skin) and a clinical visual score. The measurements were taken by a dermatologist by blinded assessment. Fifteen subjects were included. Vasoconstriction was significantly higher with the topical steroid applied after US, especially in zone 2, than without US. Vasoconstriction was increased at 1, 2, 3, 4, and 6h (e.g., chromameter score 63.4 versus 65.2, p=0.017 at 4h) and disappeared at 24h. Moreover, 2-h occlusion gave higher vasoconstriction scores than did 1-h occlusion or massage alone, whether US was applied or not. The use of low-frequency US coupled with 2-h occlusion is a synergistic way to increase the efficiency of topical steroids by enhancing skin permeability.

Probe of CYP3A by a single-point blood measurement after oral administration of midazolam in healthy elderly volunteers.

BACKGROUND: Midazolam (MDZ) is used as an assessment of human cytochrome P450 3A (CYP3A) activity. A single blood measurement is used as a marker of its activity based on an observed correlation between MDZ clearance and the 1'-hydroxymidazolam (1'-OH-MDZ): MDZ plasma ratio is assessed at 0.5 h followig the intake of a single 7.5 mg oral dose of MDZ in healthy young volunteers. In addition, a 4-h plasma MDZ measurement has been found to be an excellent predictor of AUC and CYP3A activity. OBJECTIVES: The main aim of this study was to define a single-point blood sampling in healthy elderly volunteers. The secondary objective was to investigate the pharmacological effects of a low oral dose of MDZ (5 mg) and its potential psychometric changes. METHODS: Eight healthy elderly Caucasian volunteers participated in a single-dose, open-label, non-comparative study. Each subject received a single 5 mg oral dose of MDZ. Plasma concentrations of MDZ and its major metabolite, 1'-OH-MDZ, were assayed over 12 h. Secondary assessments of critical flicker fusion (CFF), body sway and mini-mental state examination were also carried out during the 12-h post-administration period. RESULTS: A moderate correlation was observed between MDZ clearance and the 1'-OH-MDZ: MDZ plasma concentration ratio at 9 h post-dosing (Rho=0.81; p=0.04), but an even better correlation (Rho=0.99; p<0.009) was found between MDZ AUC and MDZ plasma concentration at 6 h post-dosing, with the latter value corresponding approximately to the average mean residence time (MRT) determined in our trial. This study was well-tolerated despite a significant transitory decrease (relative to baseline) in cortical arousal at 1 h post-dosing, as assessed by CFF, and a non-significant decrease (relative to baseline) in balance and vigilance also measured at 1 h and assessed on body sway, compared to baseline values. CONCLUSION: Despite the small sample size, based on the results of healthy, elderly volunteers, a single MDZ plasma measurement taken at 6 h post-oral administration may represent an accurate marker of CYP3A phenotype. This single-time-point method could be used safely for predicting drug-drug or diet interactions and identifying individuals with genetic polymorphism that affect CYP3A activity.

[Perception of written and oral information by 50 healthy volunteers from a monocentric study]. / Perception de l'information orale et écrite par 50 volontaires sains d'une étude monocentrique.

The purpose of this survey in 50 healthy volunteers from a single-centre study was to assess from a questionnaire filled in by the participants, their comprehension and evaluation of the written and oral information and the legal framework, as well as their uncertainty regarding participation, in terms of age, gender and profession. Overall satisfaction with regard to comprehension and oral information was recorded, but 42% of volunteers considered the informed consent form too long and one-quarter of them did not read it completely. Knowledge of the legal framework (20%) did not influence either their understanding or hesitation to participate. The hesitant individuals (26%) more often judged this framework to be reassuring than the non-hesitant individuals (77% versus 38%; p = 0.015). These findings concerned females, medics or paramedics and younger individuals (< or =35 years). In individuals who do not give their consent, it would be interesting to study the reasons for refusal to participate and the influence of the ethical and legal framework in clinical trials in enhancing the patients' partnership in a context of evidence-based medicine.