Antibacterial activity of Barbatimão (Stryphnodendron adstringens) against Staphylococcus aureus: in vitro and in silico studies.

We evaluated the activity of the aqueous fraction and the ethyl acetate fraction of Stryphnodendron adstringens against Staphylococcus aureus and proposed their mechanism of action. The antibacterial activity of S. adstringens fractions was evaluated against S. aureus and the cell targets were rated by docking. The fractions showed moderate antibacterial activity against S. aureus without toxicity on two mammalian cell lines. They also showed synergistic antibacterial activity with tannic acid (TA). In silico assays indicated FabG, FabZ and FabI as probable targets. The metabolic pathway for fatty acid biosynthesis in S. aureus was affected by components of S. adstringens. The synergistic effect when combining TA with S. adstringens fractions suggests a natural alternative to S. aureus control. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study describing the possible targets of action of Stryphnodendron adstringens on Staphylococcus aureus. Molecular dynamics simulations showed that the components of S. adstringens affected the metabolic pathway for fatty acid biosynthesis (FAS II) in S. aureus, inhibiting the FabI, FabG and FabZ enzymes. As tannic acid (TA) is a known inhibitor of some targets identified, we showed synergistic antibacterial activity of S. adstringens in combination with TA. This combination did not show toxicity against HaCaT and Vero cells and based on all these results we suggest that S. adstringens can be a natural and sustainable alternative to S. aureus control.

Coupling indicators and lumped-parameter modeling to assess suspended matter and soluble phosphorus losses.

For ecological and economic issues, evaluating the environmental fate of dissolved and suspended matter in catchments and river ecosystems still remains a challenge for the preservation and management of natural resources. Models are useful tools and may help to cope with this challenge, and especially to define the relationships between the state of natural systems and land and river management/uses. As it is difficult - even impossible - to carry out experiments on natural systems such as catchments, models are also useful to test hypotheses about the underlying processes acting on dissolved and suspended losses. We propose an innovative approach to achieve these objectives. By coupling environmental indicators and lumped modeling, this study aims to develop a conceptual and general framework to evaluate and test the functions that drive particulate and dissolved matter flows at the catchment and landscape scales, while respecting the constraint of parsimony for the number of model parameters. Calculated suspended matter (SM) and soluble reactive phosphorus (SRP) losses agreed well with field data. 210Pbex (excess Pb) activities in core sediments were also compared to those of 210Pbex calculated from the filling of the reservoir. Our models are parsimonious and this does not impair their accuracy in reproducing recorded outflows or evaluating the sedimentation processes associated to particulate outflows. Considering the adequacy of our models, we validate the hypothesis that river bank erosion and water table behavior are the driving processes that govern losses of particulate and solute forms of P, in the studied extensive agriculture conditions.

Measurement of the weighted peak level for occupational exposure to gradient magnetic fields for 1.5 and 3 Tesla MRI body scanners.

The purpose of this work is to give a contribution to the construction of a comprehensive knowledge of the exposure levels to gradient magnetic fields (GMF) in terms of the weighed peak (WP), especially for 3 Tesla scanners for which there are still few works available in the literature. A new generation probe for the measurement of electromagnetic fields in the range of 1 Hz-400 kHz was used to assess the occupational exposure levels to the GMF for 1.5 and 3.0 Tesla MRI body scanners, using the method of the WP according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) approach. The probe was placed at a height of 1.1 m, close to the MRI scanners, where operators could stay during some medical procedures with particular issues. The measurements were performed for a set of typical acquisition sequences for body (liver) and head exams. The measured values of WP were in compliance with ICNIRP 2010 reference levels for occupational exposures.

Measurements of computed tomography dose index for clinical scans.

Dose assessment in computed tomography is nowadays based on indicators such as the weighted computed tomography dose index (CTDIw) and the volume-weighted computed tomography dose index (CTDIvol), both measured only on single-axial scans. The aim of this study is to extend the set of CT protocols suitable in CTDIvol,w evaluation and therefore to perform measurements directly on clinical CT scans. With this purpose, the present work follows the methodology proposed by the American Association of Physicists in Medicine in the Report No. 111 and focuses on the central cumulative dose DL(0), which predicts CTDIvol,w values for scan length equal to 100 mm. All measurements performed with ion chamber and gafchromic films suggest that it is possible to achieve accurate CTDIvol,w values without selecting single-axial scans tailored to dosimetry. Therefore, it is not always necessary to split dosimetric and clinical CT scanner set-up.

A simple model to assess nitrogen and phosphorus contamination in ungauged surface drainage networks: application to the Massaciuccoli Lake Catchment, Italy.

Modeling is a common practice to evaluate factors affecting water quality in environmental systems impaired by point and nonpoint losses of N and P. Nevertheless, in situations with inadequate information, such as ungauged basins, a balance between model complexity and data availability is necessary. In this paper, we applied a simplified analytical model to an artificially drained floodplain in central-western Italy to evaluate the importance of different nutrient sources and in-stream retention processes and to identify critical source areas. We first considered only a set of chemical concentrations in water measured from February through May 2008 and from November 2008 through February 2009. We then broadened available data to include water discharge and hydraulic-head measurements to construct a hydrogeological model using MODFLOW-2000 and to evaluate the reliability of the simplified method. The simplified model provided acceptable estimates of discharge (ranging from 0.03-0.75 m s) and diffuse nutrient inputs from water table discharge and in-stream retention phenomena. Estimates of PO-P and total P retention (ranging from 1.0 to 0.6 µg m s and from 1.18 to 0.95 µg m s for PO-P and total P, respectively) were consistent with the range of variability in literature data. In contrast, the higher temporal variability of nitrate concentrations decreased model accuracy, suggesting the need for more intensive monitoring. The model also separated the dynamics of different reaches of the drainage network and identified zones considered critical source areas and buffer zones where pollutant transport is reduced.

Acute renal failure and renal replacement therapy in the postoperative period of orthotopic liver transplant patients versus nonelective abdominal surgery patients.

Acute renal failure (ARF) often complicates the postoperative period of patients undergoing orthotopic liver transplantation (OLT); it is habitually associated with high mortality rates. Similarly, patients undergoing major nonelective abdominal surgery are prone to ARF because of their frequent preexistent morbidities, abdominal sepsis, and needed for extended surgical procedures. The aim of this study was to evaluate the incidence of ARF and use of renal replacement therapy (RRT) among OLT versus nonelective abdominal surgery patients and associations with clinical outcomes. We studied all the patients admitted to a surgical intensive care unit (ICU) from January 2008 to December 2009 after OLT or nonelective abdominal surgery. The inclusion criteria were an ICU stay of at least 48 hours and without prior end-stage renal failure. OLT patients (n=84) were younger and less severly ill than surgery patients (n=60). ARF occurrence was lower among the OLT (29%) than the surgery group (47%) requiring RRT in 71% and 53% of patients due to ARF, respectively. The ICU mortality of ARF patients in both groups (29% OLT and 51% surgery) were greater than among subjects without ARF (2% and 6%). The occurrence of ARF is common among these two patient groups, and associated with increased risk of death among in surgery (+45%) versus in OLT (+27%) patients.

The association between osteoporosis and static balance in elderly women.

SUMMARY: This study aimed at answering the question: do people with high bone loss have greater postural instability? Groups were separated into group 1: women with normal bone mineral density, group 2: women with osteopenia, and group 3: women with osteoporosis. The balance was evaluated in four upright postural situations. Osteoporosis group had greater oscillation in the anteroposterior displacement in all situations compared to control group and the greatest mediolateral displacement in all situations compared to other groups. INTRODUCTION: It is not known whether the presence of osteoporosis can be considered a factor aggravating the postural control. This study aimed at answering the question: do people with high bone loss have greater postural instability? METHODS: This study was divided into three groups: group 1 (n = 20) consisting of women with normal bone mineral density, group 2 (n = 20) women with osteopenia, and group 3 (n = 20) women with osteoporosis. All the participants were submitted to evaluation of the balance using the Polhemus system in four upright postural situations. RESULTS: Osteoporosis group had greater oscillation in the anteroposterior displacement in all situations compared to control group. The osteoporosis group also showed the greatest mediolateral displacement in all situations compared to other groups. CONCLUSION: The results suggest that osteoporotic women had the worst balance, possibly due to the more pronounced body changes compared to non-osteoporotic women.

Survival and spread of Shiga toxin-producing Escherichia coli in alpine pasture grasslands.

AIMS: To determine the fate of Shiga toxin-producing Escherichia coli (STEC) strains defecated onto alpine grassland soils. METHODS AND RESULTS: During the summers of 2005 and 2006, the field survival of STEC was monitored in cowpats and underlying soils in four different alpine pasture units. A most probable number (MPN)-PCR stx assay was used to enumerate STEC populations. STEC levels ranged between 3.9 and 5.4 log(10) CFU g(-1) in fresh cowpats and slowly decreased until their complete decay (inactivation rates k < 0.04 day(-1)). PFGE typing of STEC strains isolated from faecal and soil samples assessed the persistence of various clonal types for at least 2 months in cowpats and their vertical dispersal down through the soil at a depth up to at least 20 cm. STEC cells counts in soil were always below 2 log(10) CFU g(-1), regardless of the pasture unit investigated. The soil became rapidly free of detectable STEC once the cowpat had decomposed. The eight STEC strains isolated during this study belonged to six distinct serotypes and tested positive for the gene(s) stx2, including the stx2g and stx2 NV206 variants. CONCLUSIONS: STEC were able to persist in cowpats and disseminate down through the soil but were unable to establish. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides useful information concerning the ecology of STEC in alpine pasture grasslands and may have implications for land and cattle management.

Infrared spectroscopy tracing of sediment sources in a small rural watershed (French Alps).

The present article describes a first attempt to use infrared spectroscopy to trace the origin of suspended river sediments. Fifty samples of the main potential sediment sources within a small catchment area (990 ha) in the French Alps were collected and compared with samples of suspended sediment from the river, collected on various dates during 2006 and 2007 using sediment traps. Two major categories of sediment source were identified: topsoils and river channel sediments. For the qualitative part of the study, each of these two main categories was divided into two sub-categories, that is to say, cultivated and pastureland topsoils, and riverbed and riverbank sediments. Discriminant analysis on the source samples showed that Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy can be used to differentiate between the four potential source materials. To determine whether or not immersion in the river altered the infrared spectra of these source materials, we measured the infrared spectra of samples that had been immersed in the river, in litter bags, for periods of up to 24 days. Immersion did not cause any major changes in the infrared spectra. The contribution of each type of source material to the suspended sediment in the river was quantified using partial least squares (PLS) analyses of DRIFT spectra to compare actual river sediment samples with an experimental model. This model was produced from the DRIFT spectra of a range of calibration samples produced by mixing source material samples in different ratios. The predictions of the model were valid and fell within the confidence interval calculated for the calibration set. Comparisons between suspended sediment samples and the model indicate that the predominant source of the sediment is riverbank erosion, which, in this case, is probably due to trampling by cattle.

Survival and leaching of fecal bacteria after slurry spreading on mountain hay meadows: consequences for the management of water contamination risk.

The aim of this work is to achieve a better understanding of the behavior of fecal coliform populations on the vegetation and in the soil after slurry spreading in environmental conditions, typical of vegetative growth period in mountain hay meadows. Changes in fecal coliform populations on the vegetation and in the soil were monitored in situ for 3 months after slurry spreading on 9 plots. The variations found in populations are related to the agricultural, soil. and climatic characteristics of plots and to the moisture regime of soils. These observations are compared with laboratory experiments on undisturbed soil microcosms. In absence of water flux, survival durations recorded in the laboratory and in the field are of the same order of magnitude. The data enable us to pinpoint the influence of various factors affecting the decline and transfer of fecal bacteria in the plant-soil system and consequently to discuss the risk management of water contamination by agriculture.

Use of plasma levels for antiepileptic drug monitoring in clinical practice. Gruppo Collaborativo per lo Studio dell'Epilessia.

A multi-center survey of antiepileptic treatment was conducted in Italy on 245 previously untreated ("new") patients with epilepsy and 355 patients treated for more than three months ("old" patients). Therapeutic drug monitoring (TDM) of antiepileptic drugs was evaluated in the context of routine clinical conditions, in relation to individual therapeutic problems and mode of treatment. Plasma levels (PL) were determined in 75% of "new" patients and 78% of "old" patients, with wide intercenter variability. TDM was done at 69% of the follow-up attendences for "new" patients and at 34% for "old" patients, but was apparently unrelated to specific therapeutic problems, such as poor disease control or adverse drug reactions. Plasma drug concentration measurements were made more often among patients on polytherapy. The age of the patient and the time elapsing since diagnosis did not seem to affect request patterns significantly. From these findings it appears that TDM is largely influenced by factors unrelated to the common recommendations in the literature. In addition, the use of TDM in clinical practice reflects the limitations of the available techniques.

Valproate, carnitine metabolism, and biochemical indicators of liver function. Collaborative Group for the Study of Epilepsy.

The effects of valproate (VPA) on carnitine and lipid metabolism and on liver function were assessed in 213 age- and sex-matched outpatients from five centers, with the following distribution: VPA monotherapy, 54; VPA polytherapy, 55; other monotherapies, 51; and untreated, 53. Mean total and free carnitine levels were significantly lower in patients with polytherapy; acylcarnitine was significantly higher for VPA monotherapy and the ratio of acyl- to free carnitine was significantly higher in all patients receiving VPA. Ammonia, uric acid, and bilirubin were the only tests selectively impaired with VPA. A significant correlation was found between serum ammonia and VPA dosage. Glucose, beta-lipoproteins, triglycerides, acetacetate, and beta-hydroxybutyrate were unchanged in the four groups. Sex and age appeared to interact with total and free carnitine values. Adverse drug reactions were apparently unrelated to carnitine metabolism impairment. Only a few patients had abnormal carnitine values. Our data support the assumption that carnitine deficiency and abnormal liver function due to VPA are mostly subclinical events.

Harmonic and impulse rheological tests of biomaterials.

Up to now, not so much attention has been paid concerning the dynamic rheological behaviour of soft tissues although non linear viscoelastic effects have often been reported when mechanical properties of biomaterials are concerned. In order to characterize such properties different rheological tests have been proposed, the two principal being the study of the sample stresses responses to applied strains which are either harmonic with time or of step function type. Two different apparatus have been designed in our laboratory which allow specific rheological tests on biological materials under controlled environmental conditions. With one of them, harmonic uniaxial extension tests are performed in a large domain of frequencies (.001 Hz to 100 Hz) and forces (up to 20 daN); with the other, the samples are submitted to relaxation tests in uniaxial elongation up to 5 cm deformation within time duration of the order of 20 ms. The principal characteristics, limitations and performances of such apparatus are presented and few examples of data thus obtained are given. On the basis of quasi linear viscoelasticity models, it can be shown that both two types of tests with their proper limitations are leading to the same rheological parameters.

[Replacement of the anterior cruciate ligament by carbon fibers. An experimental study]. / Remplacement du ligament croisé antérieur par des fibres de carbone. Etude expérimentale.

The authors have excised the anterior cruciate ligament in 14 sheep and replaced it by carbon fibres. The animals were sacrificed after 12 to 18 months. Eight had a satisfactory new ligament without any evidence of arthrosis and with stability of the knee. In 2 cases, there was moderate instability and arthrosis associated with a lax ligament and in 3 cases the new ligament had ruptured with severe instability and arthrosis. Microscopic examination shows a satisfactory acceptance of the carbon filament both inside the bone as well as in the joint. There was no difference between cases repaired immediately or 6 months after excision of the ligament. A study of aortic lymph nodes showed the presence of carbon particles. The rupturing strength of the new ligaments and of normal ligaments were similar. The visco-elasticity of the new ligaments was also studied and was found to be satisfactory. It was considered that the use of carbon fibre may be valuable but more studies should be done to improve the elasticity and to decrease the migration of carbon material.