An acute social stressor decreases reinforcing value of both high and low energy-dense food in college students in a randomized controlled trial

It is well known that a large portion of the population elevates their intake of high energy-dense foods during times of stress; however, it is understudied whether stress affects the reinforcing value of a food reward. Further knowledge of this relationship may help us better understand the positive correlation between reinforcing value of food and obesity. Therefore, it was tested if an acute stressor would increase the reinforcing value of low or high energy-dense food. Participants (N = 70) were randomized to a stress or no-stress condition after which they were allowed to work to gain access to a food reward and reading time. To determine if high energy-dense food was specifically affected, half the participants from each stress manipulation were randomly assigned to work for either grapes or chocolate candies. Participants in the stress condition worked less for food access than those in the no-stress condition, for both low and high energy-dense foods, but stress did not affect the reinforcing value of reading time. These results indicate that, contrary to our hypothesis, in a sample of college students, an acute stressor decreased reinforcing value of food, with no difference between a low and high energy-dense food item.

Restoration of normal sinus rhythm in atrial fibrillation: impact of reverse remodelling of right chambers on tricuspid regurgitation severity

Background

The severity of tricuspid regurgitation (TR) in patients with restored normal sinus rhythm (SR) after atrial fibrillation (AF) has been poorly assessed.

Purpose

Our study aimed to assess (1) right chamber remodelling and (2) TR severity in patients with AF who have had their rhythms restored to normal sinus.

Methods

We prospectively evaluated 94 consecutive patients hospitalized for AF who received either ablation, direct current cardioversion, or pharmacological therapy. Patients were divided into two groups according to their cardiac rhythm at 6 months follow up (6M): restoration to SR (SR group, n=54), persistence of AF (AF group, n=40). TR vena contracta (VC), TR grade severity was divided into 4 grades using an integrated approach (0: none or trace; 1: mild; 2: moderate; 3: severe TR). Two dimensional (2D) end diastolic (ED) tricuspid annulus (TA) diameter in the apical 4 chambers view, three-dimensional (3D) indexed volumes (3D Vi) of the right atrium (RA) and right ventricle (RV) in end systole (ES) and ED were acquired using transthoracic echocardiography at admission and at 6M.

Results

At 6M, in the SR group a significant improvement in TR VC (Figure A) and TR grade (Figure B) were noted, whereas there was no differences in the AF group (0.41 vs. 0.42cm, p=0.24 for TR VC; 1.70 vs. 1.76, p=0.16 for mean TR grade). In the SR group a significant reduction in 3D ES RV Vi, 2D ED TA diameter, 3D ES and ED Vi of the RA (Table) were observed. Regression of TR VC was correlated with regression of right cavities parameters (ρ=0.47, p<0.001 for 2D ED TA diameter; ρ=0.34, p<0.005 for 3D ES RA Vi; ρ=0.33, p<0.005 for 3D ED RV Vi; ρ=0.29, p<0.005 for 3D ES RV Vi).

Conclusion

Restoration of normal SR in patients with AF results in beneficial remodelling of right cavities at 6M of follow-up which were associated with a significant decrease in TR severity. Strategies for normal SR restoration in patients with AF and TR should be vigorously attempted.

TR Evolution

Funding Acknowledgement

Type of funding source: None

Impact of rhythm in non-valvular atrial fibrillation on four cardiac chamber deformation imaging

Background

Few studies have assessed the evolution of cardiac chambers deformation imaging in patients with atrial fibrillation (AF) according to cardiac rhythm outcome.

Purpose

To evaluate cardiac chamber deformation imaging in patients admitted for AF and the evolution at 6-month follow-up (M6).

Methods

In forty-one consecutive patients hospitalised for AF two-dimensional transthoracic echocardiography was performed at admission (M0) and after six months (M6) of follow up. In addition to the usual parameters of chamber size and function, chamber deformation imaging was obtained including global left atrium (LA) and right atrium (RA) reservoir strain, global left ventricular (LV) and right ventricular (RV) free wall longitudinal strain. Patients were divided into three groups according to their cardiac rhythm at M0 and M6: AF at M0 and sinus rhythm (SR) at M6 (AF-SR) (n=23), AF at M0 and AF at M6 (AF-AF) (n=11), SR at M0 (spontaneous conversion before the first echocardiography exam) and SR in M6 (SR-SR) (n=7)

Results

In comparison with SR patients (n=7), at M0, AF patients (n=34)) had lower global LA reservoir strain (+5.2 (+0.4 to 12.8) versus +33.2 (+27.0 to +51.5)%; p<0.001), lower global RA reservoir strain (+8.6 (−5.4 to 11.6) versus +24.3 (+12.3 to +44.9)%; p<0.001), lower global LV longitudinal strain (respectively −12.8 (−15.2 to −10.4) versus −19.1 (−21.8 to −18.3)%; p<0.001) and lower global RV longitudinal strain (respectively −14.2 (−17.3 to −10.7) versus −23.8 (−31.1 to −16.2)%; p=0.001). When compared with the AF-SR group at M0 the AF-AF group had no significant differences with regard to global LA and RA reservoir strain, global LV and RV longitudinal strain (Table). Between M0 and M6 there was a significant improvement in global longitudinal strain of the four chambers in the AF-SR group whereas no improvements were noted in the AF-AF and SR-SR group (Figure).

Conclusion

Initial atrial and ventricular deformations were not associated with rhythm outcome at six-month follow up in AF. The improvement in strain in all four chambers strain suggests global reverse remodelling all cardiac cavities with the restoration of sinus rhythm.

Evolution of strain between M0 and M6

Funding Acknowledgement

Type of funding source: None

Temporal (1970-2016) changes in human pressures and wetland response in the St. Lawrence River (Québec, Canada)

Temporal changes (1970-2016) in St. Lawrence River wetlands were assessed between Cornwall and Québec (≈400 km) to assess wetland response to cumulative anthropogenic pressures in the watershed. Emergent wetlands area and biomass of submerged aquatic vegetation (SAV) were contrasted among five regions subjected to sharply different water level/discharge regime (stabilized, semi-natural, tidal), nutrient concentrations and shoreline use (rural to urbanized). Between 1970 and 2016, over the growing season (April-Sept.), St. Lawrence River mean water level at Sorel dropped by ≈1 m and mean water temperature increased by ≈3 °C. Reductions in phosphorus concentrations (by ≈2-fold) were observed over time both in water and in SAV tissues, in phase with improvements of urban wastewater treatment and P-reduction in upstream Lake Ontario. Nitrate concentrations in water increased and SAV biomass decreased between the 1970s and 2008 in the downstream regions of Lake Saint-Pierre and fluvial corridor subjected to the cumulative impacts from urban centers and intensively farmed watersheds. Over the 1970-2010 period, dropping water levels yielded slightly increasing wetland areas, owing to the downslope colonization of emergent and submerged plants. In urbanized regions, emergent wetlands shifted towards drier assemblages dominated by invasive reed species. Encroachment of wetlands by agriculture accounted for most wetland losses in rural Lake Saint-Pierre, which holds the single largest area (197 km²) of continuous wetland habitat of the entire watershed. Our results highlight the strong response of riverine wetlands to a wide range of human pressures, including dropping water levels, changing nutrient concentrations, rising population and intensifying agriculture.

Diagnostic delay of pyogenic vertebral osteomyelitis and its associated factors

OBJECTIVES

Pyogenic vertebral osteomyelitis (PVO) is a rare disease with possible severe complications (e.g. sepsis and spinal cord injury). In the 1990s, diagnostic delay (DD) was often extensive as PVO has a non-specific clinical spectrum, mostly afebrile with back pain, and access to magnetic resonance imaging (MRI) was not straightforward. Our aim was to perform a new study focusing on the clinical spectrum and DD of PVO and its associated factors.

METHOD

This study examined a prospective cohort of 88 patients having PVO with microbiological identification between 15 November 2006 and 15 November 2010.

RESULTS

The 88 patients included in the study (female:male ratio 1:8) had a mean age of 64.1 years. The mean (sd) DD was 45.5 (50.4) days (range 2-280), and 46 patients (52.2%) were febrile at diagnosis. The main microorganism involved was Staphylococcus (n = 45; 51.1%). In univariate and multivariate analyses, age > 75 years, antecedent back pain, involvement of bacteria, topography of PVO, and anti-inflammatory drug intake did not affect the DD, unlike a C-reactive protein (CRP) value > 63 mg/L or a positive blood culture (DD lowered from 73 to 17 days and from 90 to 30 days, respectively). Conversely, X-ray investigation was associated with a longer DD (from 14 to 34.7 days). Severity at diagnosis was not significantly different depending on the intake of anti-inflammatory drugs.

CONCLUSIONS

Despite easier access to MRI, the DD for PVO remains long. One shortening factor is a high CRP value, which could be a useful diagnostic tool in case of back pain. Anti-inflammatory drugs seem to have no impact on DD and severity at diagnosis.

Strategy of total synthesis based on the use of Rh-catalyzed stereoselective 1,4-addition

In 1998, Hayashi and Miyaura reported the first asymmetric conjugate addition of aryl- and alkenyl-boronic acids to α,β-unsaturated ketones using chiral rhodium complexes as catalysts.

Synthesis of new bioisosteric hemiasterlin analogues with extremely high cytotoxicity

In this Letter, the synthesis and the evaluation of the cytotoxicity of new hemiasterlin analogues were reported. The indole moiety was replaced respectively by benzofurane, naphthalene and 4-bromobenzene groups. Most of these derivatives possess strong cytotoxic activity on two human tumour cell lines (KB and Hep-G2), and some analogues showed comparable cytotoxic activity to that observed for paclitaxel and ellipticine, against KB and Hep-G2 cancer cell lines.

Synthesis of new simplified hemiasterlin derivatives with α,β-unsaturated carbonyl moiety

In this Letter, we report a convenient and efficient method for the synthesis of new simplified derivatives of hemiasterlin in which the α,α-dimethylbenzylic moiety A is replaced by α,β-unsaturated aryl groups as Michael acceptor. Most of these derivatives have a strong cytotoxic activity on three human tumor cell lines (KB, Hep-G2 and MCF7). Analogs 17b and 17f showed a high cytotoxicity against KB and Hep-G2 cancer cell lines comparable to paclitaxel and ellipticine.

Measurement and modelling of radioxenon plumes in the Ottawa Valley

Since 2001 a real-time radiation monitoring network of Canadian nuclear facilities and major population centres has been implemented for response to nuclear incidents including a possible terrorist attack. Unshielded NaI(Tl) spectroscopic detectors are employed to measure gamma radiation from airborne radioactivity and radioactivity deposited on the ground. These detectors are composed of a standard 3''x3'' cylindrical NaI(Tl) spectrometers with data storage and integrated telemetry. Some of the detectors have been deployed in the Ottawa Valley near Chalk River Laboratories and Ottawa, which has a complex radioxenon environment due to the proximity of nuclear power reactors, and medical isotope facilities. Although not a health threat, these releases have provided an opportunity for the Canadian Meteorological Centre and the Commissariat à l'Energie Atomique to validate their meteorological models. The meteorological models of the two organizations are in good agreement on the origin and the source terms of these releases.

Biofilms of As(III)-oxidising bacteria: formation and activity studies for bioremediation process development

The formation and activity of an As(III)-oxidising biofilm in a bioreactor, using pozzolana as bacterial growth support, was studied for the purpose of optimising fixed-bed bioreactors for bioremediation. After 60 days of continuous functioning with an As(III)-contaminated effluent, the active biofilm was found to be located mainly near the inflow rather than homogeneously distributed. Biofilm development by the CAsO1 bacterial consortium and by Thiomonas arsenivorans was then studied both on polystyrene microplates and on pozzolana. Extra-cellular polymeric substances (EPS) and yeast extract were found to enhance bacteria attachment, and yeast extract also appears to increase the kinetics of biofilm formation. Analysis of proteins, sugars, lipids and uronic acids indicate that sugars were the main EPS components. The specific As(III)-oxidase activity of T. arsenivorans was higher (by ninefold) for planktonic cells than for sessile ones and was induced by As(III). All the results suggest that the biofilm structure is a physical barrier decreasing As(III) access to sessile cells and thus to As(III)-oxidase activity induction. The efficiency of fixed-bed reactors for the bioremediation of arsenic-contaminated waters can be thus optimised by controlling different factors such as temperature and EPS addition and/or synthesis to increase biofilm density and activity.

Paclitaxel poliglumex (PPX), cisplatin and concurrent radiation for esophageal and gastric cancer: A phase I study

15130

Background: PPX is a conjugate of paclitaxel to a polyglutamate polymer. Preclinically, PPX demonstrated a radiation enhancement factor (REF) >7.0, versus 1.5–2.0 for paclitaxel. (Milas et al Int J Rad Onc 55:2003, Li et al. Clin Cancer Res 6:2000). The maximally tolerated dose (MTD) of PPX was determined previously to be 70 mg/m2 /week with concurrent radiation. We initiated a phase I study of PPX, cisplatin, and concurrent radiation with patients with esophageal and gastric cancer. Methods: Patients with esophageal or gastric cancer receiving chemoradiation for locoregional control, adjuvant, or neoadjuvant treatment were eligible. All patients received radiation at a dose of 50.4 Gy delivered in 28 fractions (5 fractions per week for 5 1/2 weeks), and cisplatin (25 mg/m2) on days 1, 8, 15, 22, 29, and 36. PPX was given as a 10 minute infusion in escalating dosages prior to each cisplatin dose. Dose limiting toxicities (DLTs) were defined as grade 4 hematologic toxicity, esophagitis, nausea/vomiting, or dehydration, or any other grade 3/4 non-hematologic toxicity. Patients were enrolled in successive cohorts of three. The MTD was defined as the dose level at which no more than 2 of 6 patients have DLTs. Results: Eleven patients have been entered over 2 dose levels of PPX: 50 mg/m2 (six patients, dose level 1), and 60mg/m2 (5 patients, dose level 2). Five patients had esophageal cancer and six had gastric cancer. All histologies were adenocarcinomas. One of six patients treated at dose level had a DLT (esophagitis). Three of five patients had DLTs at dose level 2, including esophagitis, nausea, vomiting, and dehydration. Conclusions: PPX is a novel radiation sensitizer for patients with esophageal and gastric cancer. The MTD for PPX is 50 mg/m2 /week in combination with cisplatin 25mg/ m2 /week for 6 weeks, and 50.4 Gy concurrent radiation for patients with esophagogastric cancer. A phase II study of PPX/cisplatin and radiation will be initiated.

No significant financial relationships to disclose.

Divided medium-based model for analyzing the dynamic reorganization of the cytoskeleton during cell deformation

Cell deformability and mechanical responses of living cells depend closely on the dynamic changes in the structural architecture of the cytoskeleton (CSK). To describe the dynamic reorganization and the heterogeneity of the prestressed multi-modular CSK, we developed a two-dimensional model for the CSK which was taken to be a system of tension and compression interactions between the nodes in a divided medium. The model gives the dynamic reorganization of the CSK consisting of fast changes in connectivity between nodes during medium deformation and the resulting mechanical behavior is consistent with the strain-hardening and prestress-induced stiffening observed in cells in vitro. In addition, the interaction force networks which occur and balance to each other in the model can serve to identify the main CSK substructures: cortex, stress fibers, intermediate filaments, microfilaments, microtubules and focal adhesions. Removing any of these substructures results in a loss of integrity in the model and a decrease in the prestress and stiffness, and suggests that the CSK substructures are highly interdependent. The present model may therefore provide a useful tool for understanding the cellular processes involving CSK reorganization, such as mechanotransduction, migration and adhesion processes.

Automated radioxenon monitoring for the comprehensive nuclear-test-ban treaty in two distinctive locations: Ottawa and Tahiti

In preparation for verification of the Comprehensive Nuclear-Test-Ban-Treaty, automated radioxenon monitoring is performed in two distinctive environments: Ottawa and Tahiti. These sites are monitored with SPALAX (Systeme de Prelevement d'air Automatique en Ligne avec l'Analyse des radioXenons) technology, which automatically extracts radioxenon from the atmosphere and measures the activity concentrations of (131m,133m,133,135)Xe. The resulting isotopic concentrations can be useful to discern nuclear explosions from nuclear industry xenon emissions. Ambient radon background, which may adversely impact analyser sensitivity, is discussed. Upper concentration limits are reported for the apparently radioxenon free Tahiti environment. Ottawa has a complex radioxenon background due to proximity to nuclear reactors and medical isotope facilities. Meteorological models suggest that, depending on the wind direction, the radioxenon detected in Ottawa can be characteristic of the normal radioxenon background in the Eastern United States, Europe, and Japan or distinctive due to medical isotope production.

Involvement of the Arabidopsis thaliana AtPMS1 gene in somatic repeat instability

Mismatch repair (MMR) genes participate in the maintenance of genome stability in all organisms. Based on its high degree of sequence conservation, it seems likely that the AtPMS1 gene of Arabidopsis thaliana is part of the MMR system in this model plant. To test this hypothesis, we aimed to disrupt AtPMS1 function by over-expressing mutated alleles expected to result in a dominant negative effect. To create one mutant allele we substituted two amino acids in the MutL-box, and for the other mutant allele we deleted 87 amino acids comprising the whole MutL-box. Contrary to published reports in some eukaryotes, transgenic plants expressing these alleles did not exhibit a decrease in fertility nor any other visible phenotype. To examine the impact of these mutations on microsatellite instability, the phenotype most often observed in organisms defective in MMR, reporter lines containing a uidA (GUS) gene inactivated by the insertion of a synthetic microsatellite (G7 or G16) were used. GUS gene function in these lines can be restored following the loss of one base or the gain of two bases in the repetitive tract. This results in the observation of blue sectors on a white background following histochemical staining. In a subset of the transformants, a significant increase (2- to 28-fold) in microsatellite instability was observed relative to wild-type. This report shows that MMR function can be disrupted via a dominant negative approach, and it is the first report to describe the phenotypic consequence of disrupting the function of a MutL homolog in plants.

Increased sperm mitochondrial DNA content in male infertility

BACKGROUND

There is increasing evidence that mitochondrial DNA (mtDNA) anomalies in sperm may lead to infertility. Point mutations, deletions and the presence of a specific mtDNA haplogroup have been associated with poor sperm quality, but little attention has been paid to the role of mtDNA content.

METHODS

Using density gradient separation and swim-up methods, we selected motile sperm from 32 normal and 35 abnormal sperm samples. The mtDNA/beta-globin gene ratio was determined by real-time quantitative PCR.

RESULTS

The average mtDNA/beta-globin ratio of sperm collected from 100% density layers was 1.4 for normal sperm, 6.1 for sperm samples presenting at least one abnormal criterion [among the three criteria established by World Health Organization (1999), i.e. sperm count, motility and morphology], and 9.1 for sperm samples presenting two or more of these abnormal criteria. These differences are very highly significant (P < 0.0001). The mtDNA numbers were also much greater in sperm collected from the 40% density gradient layers (mean: 17.1, P < 0.001), known to contain the most abnormal sperm of the sperm samples, than in those collected from the 100% layers known to contain sperm with the best fertilizing ability.

CONCLUSION

Our results showed significant mtDNA amplification in sperm collected from abnormal sperm samples.

Constitutive laws and failure models for compact bones subjected to dynamic loading

Many biological tissues, such as bones and ligaments, are fibrous. The geometrical structure of these tissues shows that they exhibit a similar hierarchy in their ultra- and macro-structures. The aim of this work is to develop a model to study the failure of fibrous structures subjected to dynamic loading. The important feature of this model is that it describes failure in terms of the loss of cohesion between fibres. We have developed a model based on the lamellar structure of compact bone with fibres oriented at 0, 45 and 90 degrees to the longitudinal axis of the bone and have studied the influence of the model parameters on the failure process. Bone porosity and joint stress force at failure were found to be the most significant parameters. Using least square resolution, we deduced a phenomenological model of the lamellar structure. Finally, experimental results were found to be comparable with our numerical model.