Imaging CD19+ B Cells in an Experimental Autoimmune Encephalomyelitis Mouse Model using Positron Emission Tomography

Multiple sclerosis (MS) is the most common demyelinating central nervous system (CNS) disease affecting young adults, often resulting in neurological deficits and disability as the disease progresses. B lymphocytes play a complex and critical role in MS pathology and are the target of several therapeutics in clinical trials. Currently, there is no way to accurately select patients for specific anti-B cell therapies or to non-invasively quantify the effects of these treatments on B cell load in the CNS and peripheral organs. Positron emission tomography (PET) imaging has enormous potential to provide highly specific, quantitative information regarding the in vivo spatiotemporal distribution and burden of B cells in living subjects. This paper reports methods to synthesize and employ a PET tracer specific for human CD19⁺ B cells in a well-established B cell-driven mouse model of MS, experimental autoimmune encephalomyelitis (EAE), which is induced with human recombinant myelin oligodendrocyte glycoprotein 1-125. Described here are optimized techniques to detect and quantify CD19⁺ B cells in the brain and spinal cord using in vivo PET imaging. Additionally, this paper reports streamlined methods for ex vivo gamma counting of disease-relevant organs, including bone marrow, spinal cord, and spleen, together with high-resolution autoradiography of CD19 tracer binding in CNS tissues.

MDD patients with early life stress deactivate the frontostriatal network during facial emotion recognition paradigm: A functional MRI study

Introduction

Early life stress (ELS) is a significant risk factor for major depressive disorder (MDD) in adults. Functional magnetic resonance imaging (fMRI) studies using face emotion processing paradigms have found altered blood-oxygen-level-dependent (BOLD) responses in the cortico-limbic network both in individuals exposed to ELS and in patients with MDD. Thus, early life stress may have a long-lasting impact on brain areas responsible for the processing of socio-affective cues.

Objectives

By applying a facial emotion recognition (FER) fMRI paradigm, we examined the long-term effect of childhood adversity on brain activity in MDD patients with and without ELS.

Methods

MDD patients without ELS (MDD, N=19), those with ELS (MDD+ELS, N=21), and healthy controls (HC, N=21) matched for age, sex, and intelligence quotient underwent fMRI scanning while performing a block design FER task with faces expressing negative emotions. The severity of ELS was assessed with the 28-item Childhood Trauma Questionnaire.

Results

Both MDD and MDD+ELS patients were slightly impaired in recognizing sad faces. Statistical analysis of brain activity found that MDD+ELS patients had significantly reduced negative BOLD responses in the right anterior paracingulate gyrus, subcallosal cortex accumbens compared to HCs. Moreover, the MDD+ELS group had a significantly increased negative BOLD signal in the right postcentral and precentral gyri relative to the HC group. MDD+ELS patients had reduced negative BOLD response in their anterior paracingulate gyrus compared to the MDD group.

Conclusions

Our results support that adult MDD patients with significant ELS are impaired in facial emotion recognition and they display functional alterations in the frontostriatal circuits.

Disclosure

This work was financially supported by the Hungarian Brain Research Program (2017-1.2.1-NKP-2017-00002)

P975Composite electroanatomical maps locate rapid activity within low voltage zones in persistent AF

Funding Acknowledgements

Our research group receives an educational grant from Abbott Inc.

Introduction. Outcomes from catheter ablation of persistent AF (psAF) are not favourable. The two prevailing major directions to improve success are left atrial (LA) substrate ablation, and non pulmonary vein driver ablation. In LA substrate ablation guided by intracardiac voltage, there is debate on the most fitting mapping rhythm and the appropriate cut offs for low voltage zones (LVZ). Non pulmonary vein driver ablation requires extensive experience and relies on complex pattern recognition by the operator, introducing subjectivity, that may lead to reduced reproducibility. AF drivers have been shown to localise to LVZs. We propose an objective, patient-tailored method of identifying rapid activity within LVZs to locate drivers of psAF. 

Methods. Eleven patients (61 ± 10.8 years of age, 9 male) undergoing first time catheter ablation for psAF were included. 3D maps were collected with a double spiral 20 pole catheter, in non-cardiac triggered mode, recording 8s segments at each bipole. Mean AF voltage (AFV) a AF cycle length (AFCL) was calculated for each 8s segment using automated algorithms. Grades of rapid activity and low voltage were defined as the 10th 20th and 30th percentile of all collected points within a patient. Percentile-matched composite LVZ-ARA maps were created on a research platform. 

Results. Mean LVZ percentage of the total mapped area was 4.67 ± 2.4%, 13.95 ± 3.8%, 23.81 ± 5.7% for the 10th, 20th and 30th percentiles respectively (Table 1). Mean, percentile matched LVZ-ARA overlap area percentage of the total mapped area was 0.3 ± 0.25% (10th-10th), 0.86 ± 0.58 (20th-20th), 3.1 ± 1.9% (30th-30th). ARAs represented a small proportion of all LVZs. Location of overlap areas differed significantly between patients and were marked with colours. Multi-colour areas including purple represent LVZ, multi-colour areas excluding purple, show LVZ-ARA overlap (examples in Fig 1). 

Conclusion. Analysis of LVZ-ARA overlap by mean AFV and AFCL provides an objective method of identifying potential drivers that localise to LVZs. The identified overlap areas constituted small, occasionally disparate areas within the LVZ of the LA. By adjusting the AFCL and AFV percentiles, the overlap areas can be tailored at the operator’s discretion, maintaining reproducible, objective decision making, without the need for complex pattern recognition. If ablation is planned, established techniques can be used to target the overlap areas, such as homogenisation or transection and connection to anatomical or ablative non-conductive tissues.

AFCL 10th AFCL 20th AFCL 30th AFV 10th AFV 20th AFV 30th All patients 128 ± 13 ms 144 ± 10 ms 150 ± 9 ms 0.15 ± 0.02 mV 0.19 ± 0.03 mV 0.24 ± 0.04 mV Mean values of percentile cut offs. AFCL: AF cycle length; AFV: AF voltage

Abstract Figure. Fig 1

P967Role of low voltage ablation in catheter ablation of patients with persistent AF- a single centre experience

Funding Acknowledgements

Research grant from Abbott

Introduction

We have recently described a novel evaluation of AF voltage which correlates better with MRI-DE defined scar than sinus rhythm voltage. We evaluated the clinical efficacy of additional voltage-based substrate modification in the Persistent AF patient cohort in a single centre case series.

Methods

22 PsAF patients undergoing catheter ablation were recruited. Left atrial electroanatomical maps were created in AF before any ablation was performed in all patients. Mean peak to peak AF voltage mapping was undertaken using 8s segments of AF (<0.35mV).  PVI was then performed in all patients after which, further ablation lesions were delivered on the underlying scar tissue (transection, box formation or homogenisation).

Results

Of the 22 patients currently under follow up, 16 patients are more than 12 months after their initial procedure. 11/16 patients have had no recurrence and no patient is currently on anti-arrhythmic medication.

Conclusion

From our series, 69% of PsAF patients remain arrhythmia free at one year follow up post blanking period with a single procedure. Ablation of low voltage areas appears to infer incremental benefit in the Persistent AF population.

Table 1 Mean Age, yrs 64 ± 9 Male 19 (86.3) Diabetes mellitus 1 (4.5) Hypertension 7 (31.8) TIA/CVA 2 (9) Left ventricular EF ≥55% 22 (100.0) LA size (diameter, according to British Society of Echocardiography Guidelines) Normal -Mild 12 (54.5) Moderate - Severe 10 (45.5) Mean AF duration, months 24.2 ± 20.8 Current antiarrhythmic strategy Amiodarone 3 (13.6) Sotalol 1 (4.5) Current anticoagulation Warfarin 3 (13.6) Direct oral anticoagulants 19 (86.3) Values are mean ± SD or N (%) or duration in months ± SD AF = atrial fibrillation; CVA= cerebrovascular accident; EF = ejection fraction; LA = left atrium; TIA = transient ischaemic attack. Baseline characteristics of patients (n = 22)

Abstract Figure. Ablation sets and AF Voltage

P991Pattern of rapid activity is preserved in persistent AF in selected locations after pulmonary vein isolation

Funding Acknowledgements

Our research group receives an educational grant from Abbott Inc.

Introduction. There is evidence to suggest that structural remodelling in psAF potentially gives rise to areas of rapid cycle length activity that may act as driving mechanisms. We describe a new method to compare rapid activity (RA) in psAF prior to and after pulmonary vein isolation, in extended AF segments (EAFS). We focus on patterns of RA, based on the hypothesis that AF drivers are transient but recur in the same locations. 

Methods. Five patients (61 ± 8 years of age, 3 male) for catheter ablation of psAF were included. 3D maps were collected with a double spiral 20 pole catheter. In stable locations, pre and post PVI, 37s EAFS were recorded using 8s segments, automatically every 1s, creating a 7s overlap between segments. Dominant cycle length (DCL) was determined for every 8s segment by a fully automated algorithm. RA was defined as the rapidest 20th percentile for each patient. RA episodes consisted of continuous segments with rapid DCL (black lines in Fig 1) and terminated with a non-rapid segment (red lines on Fig 1). Episodes were truncated where overlap occurred (Box 1 and Box 2 in Fig 1). The pattern of RA was assessed by the number, cumulative duration and mean duration of RA episodes within an EAFS pre and post PVI.

Results. Mean DCL of EAFS increased significantly in 4/5 patients after PVI, the number of EAFS with rapid activity showed a reduction in all patients.  The percentage of new sites with RA post PVI was 27%. The number of sites that retained RA post PVI was 14 ± 11.3 (58.3%; Table 1).  Of these, number and cumulative duration of RA did not change in 4/5 patients, and mean duration of RA remained stable in 5/5.

Conclusion. An automated DCL algorithm shows that, in most cases, global AFCL prolongs significantly with PVI overall, but selected foci retain RA and RA patterns. These may represent active drivers, as their activity appears to be independent of their surroundings.

Table 1 Patient ID Number of segments Mean AFCL ± SD of all segments Number of EAFS with rapid activity Pre-PVI Post-PVI P Pre-PVI Post-PVI New sites 1 145 135 ± 8.9 141 ± 9.8 <0.001 94 62 15 2 121 154 ± 12.9 162 ± 15.0 <0.001 94 72 11 3 172 148 ± 13.7 160 ± 16.6 <0.001 108 82 25 4 301 172 ± 22.9 174 ± 21.5 0.418 198 189 58 5 200 177 ± 9.9 215 ± 18.1 <0.001 87 43 14 Pre and Post PVI cycle length and EAFS with rapid activity. (AFCL: AF cycle length; EAFS: Extended AF segments; PVI: Pulmonary vein isolation)

Abstract Figure.

0262 An Exploratory Examination of the Relationship Between Negative Affect, Stress and Emotional Reactivity, Mindfulness, and Sleep Incompatible Behaviors

Introduction

Stress has been identified as a barrier to engaging in positive health behaviors. Sleep interventions, including sleep hygiene recommendations, highlight stress management as an important treatment component. However, the relationship between negative emotion, stress management or emotion regulation, and positive sleep behaviors has largely been unexamined. Therefore, the current study, through secondary analyses, examined the relationships between negative affect, stress and emotional reactivity and sleep incompatible behaviors. Lastly, the indirect effect that dispositional mindfulness, as a possible self-regulatory mechanism, may have on the relationship was also examined. It was hypothesized that greater levels of stress, emotional reactivity, and negative arousal along with lower levels of dispositional mindfulness would predict higher engagement in sleep incompatible behaviors.

Methods

Participants (n=308) identified mostly as female (55.8%) and White/Caucasian (83.2%) and with an average age of 36.76 (SD = 12.20). Participants completed the Perceived Stress and Reactivity Scale (PSRS), the Positive and Negative Affect Scale (PANAS), the Sleep Behaviors Self-Rating Scale, and the Five Facet Mindfulness Questionnaire (FFMQ). A multiple regression analysis was conducted using the relevant subscales from the PSRS, PANAS, and FFMQ to predict the occurrence of behaviors incompatible with healthy sleep.

Results

The hypothesis was partially supported. Results indicated that the model significantly predicted sleep incompatible behavior (R2= .108, F(9, 299) = 4.042, p < .001), with only negative affect (β= .163, t(299) = 2.555, p = .011) and nonreactivity (β= -.219, t(299) = -2.484, p = .014) remaining significant when all variables were entered in the model.

Conclusion

The findings demonstrate that negative affect and reactivity are significant predictors of engagement in poor sleep hygiene practices. They also suggest that certain facets of dispositional mindfulness has an indirect relationship with sleep incompatible behaviors. The results may contribute to the development of sleep health interventions and highlight the need for future research.

Support

N/A

0165 The Relationship Between Anxiety Symptoms and Sleep Quality: Mediating and Moderating Factors of Pre-Sleep Arousal and Anxiety Sensitivity

Introduction

The relationship between anxiety and sleep has been well-established, with many studies demonstrating the relationship between anxiety and reduced REM time, increased sleep latency, and reduced sleep efficiency. Anxiety sensitivity, or the fear of experiencing anxiety-related sensations, has also been associated with increased sleep latency and sleep dysfunction. This delay in sleep onset may be explained by increased arousal, both physical and cognitive, immediately before sleep related to worry or anxiety. The current study examined the relationship between anxiety and subjective sleep quality through pre-sleep arousal and investigated the moderating effect of anxiety sensitivity.

Methods

Participants (n=322) were recruited from Amazon’s MTurk site, with most identifying as female (58.5%) and White/Caucasian (84.4%) and with an average age of 37.51 (SD = 12.12). Participants completed the Daily Assessment of Symptoms - Anxiety Scale (DAS-A), the Anxiety Sensitivity Index (ASI), the Pre-Sleep Arousal Scale (PSAS) and the Pittsburg Sleep Quality Index (PSQI). A moderated mediation analysis was conducted using Model 58 in PROCESS for SPSS.

Results

Results indicated that pre-sleep arousal partially mediated the relationship between anxiety and the dichotomous sleep quality variable while controlling for the covariates of age, and therapy participation, (a1= .186, p<.001, b1= .113, p<.001, c’= .038, p<.001). Additionally, the conditional effects and interactions of the moderating anxiety sensitivity variable were significant in both pathways (a1: F=24.702, p<.001; b1: χ 2 = 5.255, p=0.22).

Conclusion

These results help to identify potential mechanisms and conditions of the relationship between anxiety and sleep quality and contribute to the development of evidence-based interventions for sleep disturbance or other sleep complaints in individuals experiencing anxiety and anxiety symptoms.

Support

N/A

P1714 When the mechanism of mitral regurgitation is unclear, 3D Trans-esophageal echocardiography is the solution

Introduction

Assessment of mitral regurgitation (MR) mechanism is not always easy and may require advanced imaging techniques.

A 28-year-old male presented with significant MR three years following surgical mitral valve repair for severe MR due to mitral valve prolapse. During surgery, he underwent artificial chordal implantation on A2 scallop and Gore-Tex posterior band annuloplasty. Early post-operative transthoracic echocardiography (TTE) showed mild to moderate eccentric, posteriorly directed MR of unknown mechanism. Since the patient was asymptomatic, only regular follow-up was advised. He missed his follow-up for three years after which presented complaining of exertional dyspnea NYHA class II.

TTE showed dilated left ventricular dimensions with moderate to severe MR of unknown mechanism.

2D trans-esophageal echocardiography (TEE) (figure 1, panel A& B) showed severe, posteriorly directed mitral regurgitation, with a mass (arrow head) at the level of the mitral annulus.

3D TEE (figure 1,panel C, 3D zoom mode and panel D, true view mode) showed dehiscence (arrow head) of the annuloplasty band from the posterior mitral annulus with a wide gap measuring 83 mm² in 3D planimetred area. The patient was referred for re-do surgery.

Conclusion

3D TEE has a great added value in elucidating the mechanism of MR in obscure cases and guiding the proper management strategy.

Abstract P1714 Figure 1

Assessment of a residual municipal solid waste landfill for prospective 'landfill mining'

Landfill mining is a prospective tool for the recycling of valuable materials (waste-to-material) and secondary fuel (waste-to-energy) from old, therefore more or less stabilised municipal solid waste landfills. The main target of Horizon 2020 'SMARTGROUND' R&D was improving the availability and accessibility of data and information from both urban landfills and mining dumps through a set of activities to integrate all the data - from existing sources and new information retrieved with time progress - in a single EU database. Concerning urban landfills, a new sampling protocol was designed on the basis of the current Hungarian national municipal solid waste analysis standards, optimised for landfill mining. This protocol was then applied in a sampling campaign on a municipal solid waste landfill in Debrecen, Hungary. The composition and parameters of the landfilled materials were measured as a 12-year timescale. The total wet and dry mass of the valuable components possible for utilisation was estimated.

Gravity as Gauge Theory Squared: A Ghost Story

The Becchi-Rouet-Stora-Tyutin (BRST) transformations and equations of motion of a gravity-two-form-dilaton system are derived from the product of two Yang-Mills theories in a BRST covariant form, to linear approximation. The inclusion of ghost fields facilitates the separation of the graviton and dilaton. The gravitational gauge fixing term is uniquely determined by those of the Yang-Mills factors which can be freely chosen. Moreover, the resulting gravity-two-form-dilaton Lagrangian is anti-BRST invariant and the BRST and anti-BRST charges anticommute as a direct consequence of the formalism.

Linear and nonlinear magnetic properties of ferrofluids

Within a high-magnetic-field approximation, employing Ruelle's algebraic perturbation theory, a field-dependent free-energy expression is proposed which allows one to determine the magnetic properties of ferrofluids modeled as dipolar hard-sphere systems. We compare the ensuing magnetization curves, following from this free energy, with those obtained by Ivanov and Kuznetsova [Phys. Rev. E 64, 041405 (2001)] as well as with new corresponding Monte Carlo simulation data. Based on the power-series expansion of the magnetization, a closed expression for the magnetization is also proposed, which is a high-density extension of the corresponding equation of Ivanov and Kuznetsova. From both magnetization equations the zero-field susceptibility expression due to Tani et al. [Mol. Phys. 48, 863 (1983)] can be obtained, which is in good agreement with our MC simulation results. From the closed expression for the magnetization the second-order nonlinear magnetic susceptibility is also derived, which shows fair agreement with the corresponding MC simulation data.

Yang-Mills origin of gravitational symmetries

By regarding gravity as the convolution of left and right Yang-Mills theories together with a spectator scalar field in the biadjoint representation, we derive in linearized approximation, the gravitational symmetries of general covariance, p-form gauge invariance, local Lorentz invariance, and local supersymmetry from the flat space Yang-Mills symmetries of local gauge invariance and global super-Poincaré symmetry. As a concrete example, we focus on the new minimal (12+12) off shell version of simple four-dimensional supergravity obtained by tensoring the off shell Yang-Mills multiplets (4+4, N_{L}=1) and (3+0, N_{R}=0).

Magic square from Yang-Mills squared

We give a unified description of D=3 super-Yang-Mills theory with N=1, 2, 4, and 8 supersymmeties in terms of the four division algebras: reals (R), complexes (C), quaternions (H) and octonions (O). Tensoring left and right super-Yang-Mills multiplets with N=1, 2, 4, 8 we obtain a magic square RR, CR, CC, HR, HC, HH, OR, OC, OH, OO description of D=3 supergravity with N=2, 3, 4, 5, 6, 8, 9, 10, 12, 16.

Comparison between theory and simulations for the magnetization and the susceptibility of polydisperse ferrofluids

The influence of polydispersity on the magnetization of ferrofluids is studied based on a previously published magnetization equation of state (Szalai and Dietrich, 2011 J. Phys.: Condens. Matter 23 326004) and computer simulations. The polydispersity of the particle diameter is described by the gamma distribution function. Canonical ensemble Monte Carlo simulations have been performed in order to test these theoretical results for the initial susceptibility and the magnetization. The results for the magnetic properties of the polydisperse systems turn out to be in quantitative agreement with our present simulation data. In addition, we find good agreement between our theory and experimental data for magnetite-based ferrofluids.

Spectroscopic and Molecular Weight Studies of Polytoluidines

Poly(o-toluidine) and poly(m-toluidine) in base form have been characterized by infrared and lH NMR spectroscopy. Assignments of the proton NMR signals have been facilitated by the use of model compounds. The distinction between benzenoid and quinoid methyl resonances in the NMR permits a semi-quantitative estimation of the oxidation states of the polytoluidines. Infrared studies are consistent with a polyaniline-type backbone having pendant methyl groups. Field desorption mass spectrometry (FD-MS) was employed for estimation of the molecular weight of poly(o-toluidine). Gel-permeation chromatography of the same sample showed a bimodal elution pattern, suggesting that the FD-MS technique detects only the lower molecular weight fraction of the polymer. Despite this inherent limitation, FD-MS yields the interesting information that the polymer contains chains of both odd and even numbers of repeat units, necessitating the coexistence of different oxidation states in the base form of the polymer.

Macrocephaly in bull spermatozoa is associated with nuclear vacuoles, diploidy and alteration of chromatin condensation

Spermatozoa from 2 dairy AI (artificial insemination) bulls (A and B), identified by their abnormal spermiogram with cells depicting frequent macrocephaly, double tails and nuclear vacuoles, were case-investigated and compared to normal spermatozoa from a control AI sire (C). Head sizes were measured and morphological abnormalities scored using brightfield and differential interference contrast microscopy. The degree of sperm maturation and of resistance to acid-induced DNA denaturation in situ were determined after uploading of acridine orange using flow cytometry of 5,000 cells/sample. Nuclear fragmentation, i.e. the ratio of red to total (red + green) fluorescence, reached 7.1% and 31% in bulls A and B, compared to 2% in bull C. The proportion of immature spermatozoa, i.e. those with incomplete histone-protamine exchange and depicting higher green fluorescence compared to the main population of the control bull, reached 9.54% in A and 7.75% in B, compared to only 0.47% in the control. In the second part of this study the previously unknown chromosomal constitution of large-headed spermatozoa of bull A was investigated by fluorescence in situ hybridization using an X-Y painting probe set. The 7.5% XY-bearing cells and the presence of diploid spermatozoa detected by flow cytometry indicate a meiotic arrest in the first division in bull A, becoming the first proven case of association of macrocephaly and M1 diploidy. The diverse approaches used for the investigation of spermatozoal DNA provide insights into the etiology of macrocephaly.

Diploid spermatozoa caused by failure of the second meiotic division in a bull

An artificial insemination bull (Bos taurus) exhibiting 23% macrocephalic spermatozoa in the ejaculate was investigated. Spermatozoa with a projected head area of > or = 52 microm(2) were considered macrocephalic. Diploidy was assumed from the measurement of sperm head area and proved by flow cytometry, which was used to sort the sperm into haploid and diploid fractions. Fluorescence in situ hybridization was used to detect the sex chromosomes with an X-Y probe set. Diploid spermatozoa most likely originate from a defective second meiotic division (M2 diploids), as only 0.7% XY-bearing spermatozoa (M1 diploids) were detected in the spermatozoa of the flow cytometric diploid sort. The painting probes generated a single X or Y spot for both unsorted semen and diploid sorted spermatozoa. This indicates a close proximity of the nonpartitioned sister chromatids in the spermatozoa. The BC1.2 probe, which labels BTAYp13-12, was used to clarify the presence of the two chromatids in the singular signal of the simultaneously hybridized Y-painting probe. In scoring more than 1000 randomly sampled spermatozoa hybridized with the BC1.2 probe, 32% showed the YY diploid signal and 18% the Y signal. The sperm diploidy in this bull was caused by an incomplete partitioning of sister chromatids during the second meiotic division (M2) associated with a failure in nuclear cleavage.

Functional renormalization group approach to the sine-Gordon model

The renormalization group flow is presented for the two-dimensional sine-Gordon model within the framework of the functional renormalization group method by including the wave-function renormalization constant. The Kosterlitz-Thouless-Berezinski type phase structure is recovered as the interpolating scaling law between two competing IR attractive area of the global renormalization group flow.

Searching for DNA markers for milk production and composition on chromosome 6 in sheep

Several milk protein polymorphisms are potential tools for selection in dairy ruminants. However, research results for dairy sheep are not as conclusive as those for goats or cattle and are often controversial. The main objective of this study was to find and later use molecular genetic markers in selection to improve milk production and milk composition in Awassi ewes. Chromosome 6 was chosen because several studies have reported the presence of significant quantitative trait loci (QTL) affecting milk production traits on ovine and bovine chromosome 6. Altogether, genotypes for 13 microsatellite loci were determined for 258 ewes, which were purebred Awassi or Awassi-Merino crosses. Phenotypic data were lactation yield of milk, milk fat, protein and lactose (kg), average milk protein and fat percentage and average somatic cell count. Five out of the 13 microsatellites showed significant association with at least one of the examined traits.

Modulation of cardiac contractility through endothelin-1 release and myocardial mast cell degranulation

The aim of this study was to outline the consequences of a hypertonic saline-dextran-40 (HSD) infusion-induced peripheral flow stimulus on the ventricular function in closed-chest, pentobarbital-anesthetized dogs. We hypothesized that HSD-induced elevation in endothelin-1 (ET-1) and nitric oxide (NO) release can have a role in myocardial contractile responses; and that cardiac mast cells (MC) degranulation may be involved in this process. The consequences of disodium cromoglycate (a MC stabilizer) or ETR-p1/fl peptide (an endothelin-A receptor antagonist) treatment were evaluated. A 4 ml/kg iv HSD40 infusion significantly increased cardiac index and myocardial contractility, and resulted in a decreased peripheral resistance. The postinfusion period was characterized by significant plasma NO and ET-1 elevations, these hemodynamic and biochemical changes being accompanied by a decreased myocardial ET-1 content, NO synthase activity and enhanced myocardial MC degranulation. Disodium cromoglycate treatment inhibited the HSD40-induced elevations in myocardial contractility and MC degranulation, and similar hemodynamic changes were noted after treatment with ETR-p1/fl peptide, together with a normalized myocardial myocardial ET-1 content, NO synthesis and a significant reduction in MC degranulation. These results indicate that peripheral NO and ET-1 release modulates the cardiac contractility through myocardial ET-A receptor activation and MC degranulation.

Critical ruptures in a bundle of slowly relaxing fibers

We study the damage enhanced creep rupture of disordered materials by means of a fiber bundle model. Broken fibers undergo a slow stress relaxation modeled by a Maxwell element whose stress exponent m can vary in a broad range. Under global load sharing we show that due to the strength disorder of fibers, the lifetime t(f) of the bundle has sample-to-sample fluctuations characterized by a log-normal distribution independent of the type of disorder. We determine the Monkman-Grant relation of the model and establish a relation between the rupture life t(f) and the characteristic time t(m) of the intermediate creep regime of the bundle where the minimum strain rate is reached, making possible reliable estimates of t(f) from short term measurements. Approaching macroscopic failure, the deformation rate has a finite time power law singularity whose exponent is a decreasing function of m. On the microlevel the distribution of waiting times is found to have a power law behavior with m-dependent exponents different below and above the critical load of the bundle. Approaching the critical load from above, the cutoff value of the distributions has a power law divergence whose exponent coincides with the stress exponent of Maxwell elements.

Optimal timing for intravenous administration set replacement

BACKGROUND

Administration of intravenous therapy is a common occurrence within the hospital setting. Routine replacement of administration sets has been advocated to reduce intravenous infusion contamination. If decreasing the frequency of changing intravenous administration sets does not increase infection rates, a change in practice could result in considerable cost savings.

OBJECTIVES

The objective of this review was to identify the optimal interval for the routine replacement of intravenous administration sets when infusate or parenteral nutrition (lipid and non-lipid) solutions are administered to people in hospital via central or peripheral venous catheters.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, CINAHL, EMBASE: all from inception to February 2004; reference lists of identified trials, and bibliographies of published reviews. We also contacted researchers in the field. We did not have a language restriction.

SELECTION CRITERIA

We included all randomized or quasi-randomized controlled trials addressing the frequency of replacing intravenous administration sets when parenteral nutrition (lipid and non-lipid containing solutions) or infusions (excluding blood) were administered to people in hospital via a central or peripheral catheter.

DATA COLLECTION AND ANALYSIS

Two authors assessed all potentially relevant studies. We resolved disagreements between the two authors by discussion with a third author. We collected data for the outcomes; infusate contamination; infusate-related bloodstream infection; catheter contamination; catheter-related bloodstream infection; all-cause bloodstream infection and all-cause mortality.

MAIN RESULTS

We identified 23 references for review. We excluded eight of these studies; five because they did not fit the inclusion criteria and three because of inadequate data. We extracted data from the remaining 15 references (13 studies) with 4783 participants. We conclude that there is no evidence that changing intravenous administration sets more often than every 96 hours reduces the incidence of bloodstream infection. We do not know whether changing administration sets less often than every 96 hours affects the incidence of infection. In addition, we found that there were no differences between participants with central versus peripheral catheters; nor between participants who did and did not receive parenteral nutrition, or between children and adults.

AUTHORS' CONCLUSIONS

It appears that administration sets that do not contain lipids, blood or blood products may be left in place for intervals of up to 96 hours without increasing the incidence of infection. There was no evidence to suggest that administration sets which contain lipids should not be changed every 24 hours as currently recommended.

Head area measurements of dead, live, X- and Y-bearing bovine spermatozoa

The head area of bull spermatozoa was measured after viability and acrosome staining using trypan blue and Giemsa stains, followed by X- and Y-chromosome-specific fluorescence in situ hybridisation (FISH). The former staining made possible the categorisation of cells according to morphology and membrane integrity, whereas the latter allowed distinction of spermatozoa bearing X- and Y-chromosomes. Individual spermatozoa could be followed during the consecutive steps of staining, measurement and FISH. Using a high-resolution digital imaging system and measurement software, the head area of more than 3000 cells of five bulls was determined precisely. In all bulls, morphologically normal, viable cells with intact acrosomes were significantly smaller than dead cells with damaged acrosomes. No significant difference in the head area between X- and Y-chromosome-bearing viable, acrosome-intact spermatozoa was found in individual bulls. However, significant between-bull differences were detected in all cell categories.

Effect of swim up and Percoll treatment on viability and acrosome integrity of frozen-thawed bull spermatozoa

The aim of this study was to investigate the effect of the swim up and Percoll methods to select frozen-thawed bull spermatozoa with high quality membrane and acrosomal integrity and final concentration. Semen samples from six Holstein-Friesian bulls were examined. The whole experiment was repeated three times. Before and after both treatments, spermatozoa were subjected to a double-staining method and evaluated by brightfield light microscope using 40x dry, or 100x oil immersion objectives. The concentration of spermatozoa evaluated by haemocytometer was 8.8 x 10(7)/ml after thawing, and the percentage of live cells with intact acrosome was 45.8%. Both treatments significantly increased the proportion of live spermatozoa compared with no treatment, and the use of Percoll gradient resulted in a significantly higher percentage of living cells with an intact acrosome (88.2%) than the swim up method (69.4%). The concentration of spermatozoa after Percoll separation (9.3 x 10(6)/ml) was higher than that after the swim up method (5.8 x 10(6)/ml). These results indicate that spermatozoa with a higher viability and acrosome integrity can be obtained by Percoll separation than by the swim up method. Therefore the use of Percoll-treated spermatozoa in IVF systems can be more expedient.

Right-sided cervical aortic arch with stenosis--treatment with an extra-anatomic bypass graft

Right-sided cervical aortic arch is a very rare vascular anomaly that may lead to stenosis development. Anatomic repair may be impeded by its high course or by abnormal branching of the supraaortic vessels, or both. This report will describe the treatment of a stenotic right-sided cervical aortic arch using an extra-anatomic bypass graft without extracorporeal support in an 11-year-old girl.

The influence of significant others on attitudes, subjective norms and intentions regarding dietary supplement use among adolescent athletes

Dietary supplement use has increased significantly over the past decade. The use of supplements among adolescents seems to be influenced by their beliefs and attitudes. The influence of coaches, parents, and athletic trainers also may be important. The purpose of this study was (1) to determine whether attitudes are a better predictor of adolescents' intentions to use dietary supplements than are subjective norms, and (2) to assess the influence of significant others (coaches, parents, and trainers) on attitudes, subjective norms, and intentions among adolescent athletes. Adolescents (N = 1,626) who were enrolled in grades six through twelve in nine public schools completed a self-report questionnaire that measured attitudes, subjective norms, and intentions regarding dietary supplement use. Results indicated that attitudes were a better predictor of intentions to use dietary supplements than were subjective norms. It was also found that trainers had more influence on the attitudes, subjective norms, and intentions of adolescents regarding supplement use than did parents and coaches. Implications for prevention are addressed.