Determination of neptunium in environmental samples by extraction chromatography after valence adjustment

Neptunium(V) ions are unstable in acid media, which limits their extraction on chromatographic resins. We developed a novel analytical method to measure Np by either α-spectrometry or inductively coupled plasma mass spectrometry (ICP-MS) after extraction chromatography as Np(VI). We investigated the reactivity of various oxidizing reagents, and determined the retention capacity of Np(IV, V, and VI) on various extraction chromatographic supports. A simple method using two UTEVA resins was used to rapidly detect Np in soil and sediment samples.     

Glycaemic response to foods: impact on satiety and long-term weight regulation

Should future nutritional recommendations for the general population take into account the notion of glycaemic index (GI)? This question is all the more legitimate as the glycaemic response to foods seems to be a factor that affects satiety and could therefore affect food intake. The aim of this review was to evaluate whether altering the glycaemic response per se can modulate satiety and to assess the short-term and long-term consequences. A systematic review of human intervention studies was performed. Confounding factors that may influence both GI and satiety were taken into consideration when selecting the studies. Thirty-two studies were thus selected and analysed. There is evidence from the short-term studies (1 day) that low-glycaemic foods or meals have higher satietogenic effect than high-glycaemic foods or meals. This substantiates claims such as 'low-GI foods help one to feel fuller for longer than equivalent high-GI foods'. The mechanisms involved may be the specific effect of blood glucose levels on satiety (glucostatic theory) and other stimuli (e.g. peptides) involved in the control of appetite. In some studies, however it seems difficult to tease out the separate effect of the lowering of postprandial glycaemia per se and fibres. Because of the increasing number of confounding variables in the available long-term studies, it is not possible to conclude that low-glycaemic diets mediate a health benefit based on body weight regulation. The difficulty of demonstrating the long-term health benefit of a satietogenic food or diet may constitute an obstacle to the recognition of associated claims.     

Sucrose or honey at breakfast have no additional acute hyperglycaemic effect over an isoglucidic amount of bread in Type 2 diabetic patients

Summary Exclusion of simple sugars from the diabetic diet is not always followed by patients and may not even be as crucial as was hitherto thought. We tested three types of mixed breakfasts (400 kcal, 50 g HCO) including an isoglucidic amount either of white bread (30 g), honey (20 g) or sucrose (15 g), at the critical morning period i.e. for breakfast, in a group of 21 Type 2 (non-insulin-dependent) diabetic patients (6 well- and 15 badly controlled). Mean plasma glucose and insulin levels were comparable on the three occasions: respectively with bread, sucrose and honey, peak glucose values were 18 mmol/l, 17.7 mmol/l and 17.5 mmol/l in the uncontrolled group versus 13.9 mmol/l, 12.8 mmol/l and 12.7 mmol/l in the well-controlled group. Peak insulin values were 33.6 mU/l,34.0 mU/l and 36.3 mU/l (p>0.05) in uncontrolled patients against 57.5 mU/l, 54.8 mU/l and 52.5 mU/l in well-controlled subjects (p>0.05). The mean increment in peak plasma glucose values for the three breakfasts was as follows: 6.9 mmol/l, 6.3 mmol/l and 6.2 mmol/l for the uncontrolled group against 7.2 mmol/l, 5.9 mmol/l and 6.2 mmol/l in well-controlled subjects; the mean increment in peak plasma insulin levels was 21.8 mU/l, 22.0 mU/l and 24.2 mU/l in the controlled group versus 38.2 mU/l, 32.0 mU/l and 34.7 mU/l in the well-controlled subjects, all values being non-significantly different (p>0.05). We conclude that, in acute conditions, simple sugars have no additional hyperglycaemic effect over an isoglucidic amount of bread in well- and in badly controlled Type 2 diabetic patients, even at breakfast.     

Relations between transit time, fermentation products, and hydrogen consuming flora in healthy humans.

BACKGROUND/AIMS: To investigate whether transit time could influence H2 consuming flora and certain indices of colonic bacterial fermentation. METHODS: Eight healthy volunteers (four methane excretors and four non-methane excretors) were studied for three, three week periods during which they received a controlled diet alone (control period), and then the same diet with cisapride or loperamide. At the end of each period, mean transit time (MTT) was estimated, an H2 lactulose breath test was performed, and stools were analysed. RESULTS: In the control period, transit time was inversely related to faecal weight, sulphate reducing bacteria counts, concentrations of total short chain fatty acids (SCFAs), propionic and butyric acids, and H2 excreted in breath after lactulose ingestion. Conversely, transit time was positively related to faecal pH and tended to be related to methanogen counts. Methanogenic bacteria counts were inversely related to those of sulphate reducing bacteria and methane excretors had slower MTT and lower sulphate reducing bacteria counts than non-methane excretors. Compared with the control period, MTT was significantly shortened (p < 0.05) by cisapride and prolonged (p < 0.05) by loperamide (73 (11) hours, 47 (5) hours and 147 (12) hours for control, cisapride, and loperamide, respectively, mean (SD)). Cisapride reduced transit time was associated with (a) a significant rise in faecal weight, sulphate reducing bacteria, concentrations of total SCFAs, and propionic and butyric acids and breath H2 as well as (b) a significant fall in faecal pH and breath CH4 excretion, and (c) a non-significant decrease in the counts of methanogenic bacteria. Reverse relations were roughly the same during the loperamide period including a significant rise in the counts of methanogenic bacteria and a significant fall in those of sulphate reducing bacteria. CONCLUSIONS: Transit time differences between healthy volunteers are associated with differences in H2 consuming flora and certain indices of colonic fermentation. Considering the effects of some fermentation products on intestinal morphology and function, these variations may be relevant to the pathogenesis of colorectal diseases.     

Association between outdoor ozone and compensated acute respiratory diseases among workers in Quebec (Canada)

Respiratory effects of ozone in the workplace have not been extensively studied. Our aim was to explore the relationship between daily average ozone levels and compensated acute respiratory problems among workers in Quebec between 2003 and 2010 using a time-stratified case-crossover design. Health data came from the Workers’ Compensation Board. Daily concentrations of ozone were estimated using a spatiotemporal model. Conditional logistic regressions, with and without adjustment for temperature, were used to estimate odds ratios (ORs, per 1 ppb increase of ozone), and lag effects were assessed. Relationships with respiratory compensations in all industrial sectors were essentially null. Positive non-statistically significant associations were observed for outdoor sectors, and decreased after controlling for temperature (ORs of 0.98; 1.01 and 1.05 at Lags 0, 1 and 2 respectively). Considering the predicted increase of air pollutant concentrations in the context of climate change, closer investigation should be carried out on outdoor workers.     

Lifelong environmental enrichment in rats: impact on emotional behavior, spatial memory vividness, and cholinergic neurons over the lifespan

We assessed lifelong environmental enrichment effects on possible age-related modifications in emotional behaviors, spatial memory acquisition, retrieval of recent and remote spatial memory, and cholinergic forebrain systems. At the age of 1 month, Long–Evans female rats were placed in standard or enriched rearing conditions and tested after 3 (young), 12 (middle-aged), or 24 (aged) months. Environmental enrichment decreased the reactivity to stressful situations regardless of age. In the water maze test, it delayed the onset of learning deficits and prevented age-dependent spatial learning and recent memory retrieval alterations. Remote memory retrieval, which was altered independently of age under standard rearing conditions, was rescued by enrichment in young and middle-aged, but unfortunately not aged rats. A protected basal forebrain cholinergic system, which could well be one out of several neuronal manifestations of lifelong environmental enrichment, might have contributed to the behavioral benefits of this enrichment.     

Circumferential arthrodesis using PEEK cages at the lumbar spine

Usual interbody cages at the lumbar spine are made of titanium or carbon fiber-polyetheretherketone (PEEK). Pure PEEK cages have more recently been proposed for its lower elasticity modulus. The goal of our study was to investigate a series of patients with circumferential fixation using anterior PEEK cages for degenerative lumbar spine disorders with a specific interest in the local lordosis. Fifty-seven consecutive patients aged 54.6 years (29 to 75) were reviewed. The level of arthrodesis varied from L2L3 to L5S1. The clinical status and the radiologic variations in local lordosis at the level of arthrodesis were measured. Decrease in lordosis at follow-up was tested in a multivariate analysis regarding age, obesity, spinal level, bone graft amount, type of posterior instrumentation, postoperative lordosis increase, and cage height. The average follow-up was 5.7 years (4 to 8). Clinical outcomes were excellent or good in 49 cases. Fusion was definite in 56 cases. Although 47 patients had no change in lordosis after surgery, 10 cases showed lordosis increase (8.2 degrees; 5 to 12). At follow-up, local lordosis decreased in 13 cases (5.6 degrees; 4 to 8). The linear model was significant (P<0.001; R=0.590) showing that loss in lordosis was related with postoperative lordosis increase (P=0.01), cage height (P<0.001), posterior instrumentation rigidity (P=0.026), age (P=0.047), and low level (P=0.013). Lumbar circumferential arthrodesis using PEEK cages provided good clinical results and fusion rate. However, lordosis correction was not maintained at follow-up, especially at lower levels, using high cages, in older patients, and when associated with a rigid primary posterior instrumentation. Regarding the last point, this is likely that the order of the instrumentation (posterior first, then anterior) played a role in the loss of lordosis in case of rigid posterior fixation.