Altered Hippocampal Glutamatergic Neurotransmission and Cognitive Impairment in APP Knock-In Mice

It is well established that glutamatergic neurotransmission plays an essential role in learning and memory. Previous studies indicate that glutamate dynamics shift with Alzheimer's disease (AD) progression, contributing to negative cognitive outcomes. In this study, we characterized hippocampal glutamatergic signaling with age and disease progression in a knock-in mouse model of AD (APPNL-F/NL-F). At 2-4 and 18+ months old, male and female APPNL/NL, APPNL-F/NL-F, and C57BL/6 mice underwent cognitive assessment using Morris water maze (MWM) and Novel Object Recognition (NOR). Then, basal and 70 mM KCl stimulus-evoked glutamate release was measured in the dentate gyrus (DG), CA3, and CA1 regions of the hippocampus using a glutamate-selective microelectrode in anesthetized mice. Glutamate recordings support elevated stimulus-evoked glutamate release in the DG and CA3 of young APPNL-F/NL-F male mice that declined with age compared to age-matched control mice. Young female APPNL-F/NL-F mice exhibited increased glutamate clearance in the CA1 that slowed with age compared to age-matched control mice. Male and female APPNL-F/NL-F mice exhibited decreased CA1 basal glutamate levels, while males also showed depletion in the CA3. Cognitive assessment demonstrated impaired spatial cognition in aged male and female APPNL-F/NL-F mice, but only aged females displayed recognition memory deficits compared to age-matched control mice. These findings confirm a sex-dependent hyper-to-hypoactivation glutamatergic paradigm in APPNL-F/NL-F mice. Further, data illustrate a sexually dimorphic biological aging process resulting in a more severe cognitive phenotype for female APPNL-F/NL-F mice than their male counterparts. Research outcomes mirror that of human AD pathology and provide further evidence of divergent AD pathogenesis between sexes.

Identification of a Preliminary Plasma Metabolome-based Biomarker for Circadian Phase in Humans

Measuring individual circadian phase is important to diagnose and treat circadian rhythm sleep-wake disorders and circadian misalignment, inform chronotherapy, and advance circadian science. Initial findings using blood transcriptomics to predict the circadian phase marker dim-light melatonin onset (DLMO) show promise. Alternatively, there are limited attempts using metabolomics to predict DLMO and no known omics-based biomarkers predict dim-light melatonin offset (DLMOff). We analyzed the human plasma metabolome during adequate and insufficient sleep to predict DLMO and DLMOff using one blood sample. Sixteen (8 male/8 female) healthy participants aged 22.4 ± 4.8 years (mean ± SD) completed an in-laboratory study with 3 baseline days (9 h sleep opportunity/night), followed by a randomized cross-over protocol with 9-h adequate sleep and 5-h insufficient sleep conditions, each lasting 5 days. Blood was collected hourly during the final 24 h of each condition to independently determine DLMO and DLMOff. Blood samples collected every 4 h were analyzed by untargeted metabolomics and were randomly split into training (68%) and test (32%) sets for biomarker analyses. DLMO and DLMOff biomarker models were developed using partial least squares regression in the training set followed by performance assessments using the test set. At baseline, the DLMOff model showed the highest performance (0.91 R2 and 1.1 ± 1.1 h median absolute error ± interquartile range [MdAE ± IQR]), with significantly (p < 0.01) lower prediction error versus the DLMO model. When all conditions (baseline, 9 h, and 5 h) were included in performance analyses, the DLMO (0.60 R2; 2.2 ± 2.8 h MdAE; 44% of the samples with an error under 2 h) and DLMOff (0.62 R2; 1.8 ± 2.6 h MdAE; 51% of the samples with an error under 2 h) models were not statistically different. These findings show promise for metabolomics-based biomarkers of circadian phase and highlight the need to test biomarkers that predict multiple circadian phase markers under different physiological conditions.

POS1465-HPR THE RELATIONSHIP BETWEEN SEDENTARY BEHAVIOR AND SLEEP IN RHEUMATOID ARTHRITIS: A CROSS-SECTIONAL STUDY

Background:

Rheumatoid arthritis (RA) is a chronic, autoimmune inflammatory condition that affects 0.5% of the adult population worldwide (1). Sedentary behavior (SB) is any waking behavior characterized by an energy expenditure of ≤1.5 METs (metabolic equivalent) and a sitting or reclining posture, e.g. computer use (2) and has a negative impact on health in the RA population (3). Sleep is an important health behavior, but sleep quality is an issue for people living with RA (4, 5). Poor sleep quality is associated with low levels of physical activity in RA (4) however the association between SB and sleep in people who have RA has not been examined previously.

Objectives:

The aim of this study was to investigate the relationship between SB and sleep in people who have RA.

Methods:

A cross-sectional study was conducted. Patients were recruited from rheumatology clinics in a large acute public hospital serving a mix of urban and rural populations. Inclusion criteria were diagnosis of RA by a rheumatologist according to the American College of Rheumatology criteria age ≥ 18 and ≤ 80 years; ability to mobilize independently or aided by a stick; and to understand written and spoken English. Demographic data on age, gender, disease duration and medication were recorded. Pain and fatigue were measured by the Visual Analogue Scale (VAS), anxiety and depression were assessed using the Hospital Anxiety and Depression Scale (HADS), and sleep quality was assessed using the Pittsburgh Sleep Quality Index. SB was measured using the ActivPAL4™ activity monitor, over a 7-day wear period. Descriptive statistics were calculated to describe participant characteristics. Relationships between clinical characteristics and SB were examined using Pearson’s correlation coefficients and regression analyses.

Results:

N=76 participants enrolled in the study with valid data provided by N=72 participants. Mean age of participants was 61.5years (SD10.6) and the majority 63% (n = 47) were female. Participant mean disease duration was 17.8years (SD10.9). Mean SB time was 533.7 (SD100.1) minutes (8.9 hours per day/59.9% of waking hours). Mean sleep quality score was 7.2 (SD5.0) (Table 1). Correlation analysis and regression analysis found no significant correlation between sleep quality and SB variables. Regression analysis demonstrated positive statistical associations for SB time and body mass index (p-value=0.03846, R2 = 0.05143), SB time and pain VAS (p-value=0.009261, R2 = 0.07987), SB time and HADS (p-value = 0.009721, R2 = 0.08097) and SB time and HADSD (p-value = 0.01932, R2 = 0.0643).

Conclusion:

We found high levels of sedentary behavior and poor sleep quality in people who have RA, however no statistically significant relationship was found in this study. Future research should further explore the complex associations between sedentary behavior and sleep quality in people who have RA.

References:

[1]Carmona L, et al. Rheumatoid arthritis. Best Pract Res Clin Rheumatol 2010;24:733–745.

[2]Anon. Letter to the editor: standardized use of the terms “sedentary” and “sedentary behaviours”. Appl Physiol Nutr Metab = Physiol Appl Nutr Metab 2012;37:540–542.

[3]Fenton, S.A.M. et al. Sedentary behaviour is associated with increased long-term cardiovascular risk in patients with rheumatoid arthritis independently of moderate-to-vigorous physical activity. BMC Musculoskelet Disord 18, 131 (2017).

[4]McKenna S, et al. Sleep and physical activity: a cross-sectional objective profile of people with rheumatoid arthritis. Rheumatol Int. 2018 May;38(5):845-853.

[5]Grabovac, I., et al. 2018. Sleep quality in patients with rheumatoid arthritis and associations with pain, disability, disease duration, and activity. Journal of clinical medicine, 7(10)336.

Table 1.

Sleep quality in people who have RA

Sleep variableBed Time N(%) before 10pm13(18%) 10pm-12pm43 (60%) after 12pm16 (22%)Hours Sleep mean(SD)6.56 (1.54)Fall Asleep minutes mean(SD)33.3(27.7)Night Waking N(%)45(63%)Self-Rate Sleep mean(SD)2.74 (0.90)Hours Sleep mean(SD)6.56 (1.54)

Disclosure of Interests:

None declared

0050 Identification of a Plasma Metabolome-Based Biomarker for Dim-Light Melatonin Offset and Onset in Humans

Introduction

Easily measuring individual circadian timing is increasingly important to inform personalized chronotherapy, screen for circadian disorders and circadian misalignment, and advance circadian research. Findings from multiple studies show that transcriptomics is a viable method to estimate dim-light melatonin onset (DLMO), but no published omics-based findings have predicted dim-light melatonin offset (DLMOff), and only one known study has used metabolomics to predict DLMO. Here, we developed and tested a plasma metabolomics-based biomarker of circadian phase using DLMO and DLMOff as phase markers.

Methods

Sixteen (8M/8F) healthy participants aged 22.4 ± 4.8y (mean ± SD) completed an in-laboratory study with 3 baseline days (9h sleep opportunity/night), followed by a randomized cross-over protocol with 9h sleep and 5h sleep conditions, each lasting 5 days. Blood was collected every 4h on the final 24h of each condition for untargeted metabolomics analyses. DLMO and DLMOff were determined during the final 24h of each condition. Samples from all conditions were randomly split into training (68%) and test (32%) datasets. DLMO and DLMOff models were developed using partial least squares regression in the training dataset and validated in the test dataset.

Results

When validating with the test dataset, R2 for the DLMO model was 0.60, median absolute error (MdAE) was 2.2 ± 2.8h (± interquartile range), and 44% of samples had MdAE under 2h. R2 for the DLMOff model was 0.62, MdAE was 1.8 ± 2.6, and 51% of samples had MdAE under 2h. The DLMOff model predicted baseline samples, under conditions of 9h sleep and controlled food intake, with an R2 of 0.91 and MdAE 1.1 ± 1.1h.

Conclusion

These findings show promise for metabolomics-based biomarkers of circadian phase and highlight the need for biomarker efforts to predict multiple circadian phase markers. Additional analyses with an independent validation dataset will help advance these initial findings.

Support

NIH-R01HL085705, NIH-R01HL109706, NIH-R01HL132150, NIH-K01HL145099, NIH-F32DK111161, and NIH-UL1TR000154; and Sleep Research Society Foundation 011-JP-16;

Hemodynamic response to non-pneumatic anti-shock compression garments in patients with renal dysfunction

Background

Patients with chronic kidney disease are at higher risk of developing cardiovascular disease. Chronic exposure to intermittent hemodialysis may be a source of added stress to the cardiovascular system; intradialytic hypotension is a common complication of hemodialysis, and repeated events may lead to hemodynamic stress and ischemic injuries. Administration of non-pneumatic compression stockings to the lower limbs has demonstrated hemodynamic stabilizing effects in other settings and may provide similar benefits in the kidney disease population. Therefore, we conducted this pilot study assessing the feasibility and tolerability of the application of non-pneumatic compression stockings to patients with kidney disease. We also assessed the changes in hemodynamic measurements following the application of the compression stockings to explore the biological feasibility of this being an effective intervention for intradialytic hypotension.

Methods

Fifteen individuals were enrolled in the study (5 healthy, 5 chronic kidney disease patients, and 5 dialysis patients). Outcomes including hemodynamic parameters such as cardiac output, peripheral vascular resistance, and blood pressure were measured using continuous pulse wave analysis. Changes in global longitudinal strain were measured via echocardiography. These outcome measurements were made before and after the application of compression stockings.

Results

All study participants tolerated the compression garments well and without complication. Hemodynamic response to lower body compression caused varying effects on cardiac output, mean arterial pressure and global longitudinal strain. Some individuals saw large improvements in hemodynamic parameters while in others the opposite effect was observed. No consistent response was elicited.

Conclusions

Application of compression stockings to patients with renal dysfunction is well-tolerated. However, significant variations in hemodynamic outcomes exist, and may be a barrier for larger scale trials without prior identification of specific patient characteristics indicating likely benefit from the application of external compression.

Trial registration

ClinicalTrials.gov, Identifier: NCT02915627, Registration Date: Sept 27, 2016.

AMON: annotation of metabolite origins via networks to integrate microbiome and metabolome data

Background

Untargeted metabolomics of host-associated samples has yielded insights into mechanisms by which microbes modulate health. However, data interpretation is challenged by the complexity of origins of the small molecules measured, which can come from the host, microbes that live within the host, or from other exposures such as diet or the environment.

Results

We address this challenge through development of AMON: Annotation of Metabolite Origins via Networks. AMON is an open-source bioinformatics application that can be used to annotate which compounds in the metabolome could have been produced by bacteria present or the host, to evaluate pathway enrichment of host verses microbial metabolites, and to visualize which compounds may have been produced by host versus microbial enzymes in KEGG pathway maps.

Conclusions

AMON empowers researchers to predict origins of metabolites via genomic information and to visualize potential host:microbe interplay. Additionally, the evaluation of enrichment of pathway metabolites of host versus microbial origin gives insight into the metabolic functionality that a microbial community adds to a host:microbe system. Through integrated analysis of microbiome and metabolome data, mechanistic relationships between microbial communities and host phenotypes can be better understood.

Movement patterns of players in the Australian Women's Rugby League team during international competition

OBJECTIVES

To describe the movement patterns of the Australian Women's Rugby League team during international competition.

DESIGN

Retrospective observational study.

METHODS

Global Positioning Systems technology recorded the movements of players from the Australian Women's Rugby League team (n=31) during seven international rugby league matches. A subgroup of players (n=18) that played at least 80min in a match were categorized into three positional groups: forwards (n=7), backs (n=7) and halves (n=4), and analysed for external outputs that were classified into multiple speed zones. Mean speed (mmin^-1) and mean speed when travelling >12kmh^-1 (MS₁₂; mmin^-1) were calculated for each 10% interval of playing time of both groups to assess changes in match intensity.

RESULTS

Total distance travelled was greater in the first half (3332.9m compared to 3249.0m), along with distances travelled at speeds >15kmh^-1 (p<0.05), whereas players travelled further at speeds <6kmh^-1 in the second half (p=0.005). Backs travelled further at speeds <6kmh^-1 (p=0.002) and >15kmh^-1 (p=0.007) compared to forwards. Mean speed significantly reduced across the first and second halves (p<0.05), while MS₁₂ reduced by ∼40% in the first half of the match (i.e. first ∼5min compared to the last ∼5min).

CONCLUSION

These results provide coaches with sport-specific activity profiles of female rugby league players that can be used to individualise training prescription. Given that match-intensity deteriorated across the first and second halves, programs may be targeted at improving endurance and supramaximal exercise tolerance in order for female players to withstand high match-demands of international competition.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Dynamics of the Electromagnetic Fields Induced by Fast Electron Propagation in Near-Solid-Density Media

The propagation of fast electron currents in near solid-density media was investigated via proton probing. Fast currents were generated inside dielectric foams via irradiation with a short (∼0.6  ps) laser pulse focused at relativistic intensities (Iλ^{2}∼4×10^{19}  W cm^{-2} μm^{2}). Proton probing provided a spatially and temporally resolved characterization of the evolution of the electromagnetic fields and of the associated net currents directly inside the target. The progressive growth of beam filamentation was temporally resolved and information on the divergence of the fast electron beam was obtained. Hybrid simulations of electron propagation in dense media indicate that resistive effects provide a major contribution to field generation and explain well the topology, magnitude, and temporal growth of the fields observed in the experiment. Estimations of the growth rates for different types of instabilities pinpoints the resistive instability as the most likely dominant mechanism of beam filamentation.

Young Drug Users: a Vulnerable Population and an Underutilized Resource in HIV/HCV Prevention

PURPOSE OF REVIEW

The social networks of people who inject drugs (PWID) have long been studied to understand disease transmission dynamics and social influences on risky practices. We illustrate how PWID can be active agents promoting HIV, HCV, and overdose prevention.

RECENT FINDINGS

We assessed drug users' connections and interactions with others at risk for HIV/HCV in three cities: New York City (NYC), USA (n = 539); Pereira, Colombia (n = 50); and St. Petersburg, Russia (n = 49). In all three cities, the majority of participants' network members were of a similar age as themselves, yet connections across age groups were also present. In NYC, knowing any opioid user(s) older than 29 was associated with testing HCV-positive. In NYC and St. Petersburg, a large proportion of PWID engaged in intravention activities to support safer injection and overdose prevention; in Pereira, PWID injected, had sex, and interacted with other key groups at risk. People who use drugs can be active players in HIV/HCV and overdose risk- reduction; their networks provide them with ample opportunities to disseminate harm reduction knowledge, strategies, and norms to others at risk. Local communities could augment prevention programming by empowering drug users to be allies in the fight against HIV and facilitating their pre-existing health-protective actions.

Transition Metal Single-Molecule Magnets: A {Mn31} Nanosized Cluster with a Large Energy Barrier of ∼60 K and Magnetic Hysteresis at ∼5 K

The first {Mn₃₁} cluster (1) has been prepared from carboxylate ions and the chelating/bridging ligand α-methyl-2-pyridine-methanol. Compound 1 possesses a unique nanosized structural topology with one of the largest energy barriers reported to-date for high-nuclearity 3d-metal clusters. Single-crystal magnetic hysteresis studies reveal the presence of hysteresis loops below 5 K, one of the highest temperatures below which molecular hysteresis has been observed for 3d-based SMMs.

Post-mortem prediction of primal and selected retail cut weights of New Zealand lamb from carcass and animal characteristics

Post-mortem measurements (cold weight, grade and external carcass linear dimensions) as well as live animal data (age, breed, sex) were used to predict ovine primal and retail cut weights for 792 lamb carcases. Significant levels of variance could be explained using these predictors. The predictive power of those measurements on primal and retail cut weights was studied by using the results from principal component analysis and the absolute value of the t-statistics of the linear regression model. High prediction accuracy for primal cut weight was achieved (adjusted R(2) up to 0.95), as well as moderate accuracy for key retail cut weight: tenderloins (adj-R(2)=0.60), loin (adj-R(2)=0.62), French rack (adj-R(2)=0.76) and rump (adj-R(2)=0.75). The carcass cold weight had the best predictive power, with the accuracy increasing by around 10% after including the next three most significant variables.

Postoperative Imaging Findings following Sigmoid Sinus Wall Reconstruction for Pulse Synchronous Tinnitus

BACKGROUND AND PURPOSE

Transmastoid sigmoid sinus wall reconstruction is a surgical technique increasingly used for the treatment of pulsatile tinnitus arising from sigmoid sinus wall anomalies. The imaging appearance of the temporal bone following this procedure has not been well-characterized. The purpose of this study was to evaluate the postoperative imaging appearance in a group of patients who underwent this procedure.

MATERIALS AND METHODS

The medical records of 40 consecutive patients who underwent transmastoid sigmoid sinus wall reconstruction were reviewed. Thirteen of 40 patients underwent postoperative imaging. Nineteen CT and 7 MR imaging examinations were assessed for the characteristics of the materials used for reconstruction, the impact of these on the adjacent sigmoid sinus, and complications.

RESULTS

Tinnitus resolved in 38 of 40 patients. Nine patients were imaged postoperatively for suspected complications, including dural sinus thrombosis, facial swelling, and wound drainage. Two patients underwent imaging for persistent tinnitus, and 2, for development of tinnitus on the side contralateral to the side of surgery. The materials used for reconstruction (NeuroAlloderm, HydroSet, bone pate) demonstrated characteristic imaging appearances and could be consistently identified. In 5 of 13 patients, there was extrinsic compression of the sigmoid sinus by graft material. Dural sinus thrombosis occurred in 2 patients.

CONCLUSIONS

The imaging findings following sigmoid sinus wall repair are characteristic. Graft materials may result in extrinsic compression of the sigmoid sinus, and this finding may be confused with dural venous thrombosis. Awareness of the imaging characteristics of the graft materials used enables this differentiation.

Virological failure and development of new resistance mutations according to CD4 count at combination antiretroviral therapy initiation

Objectives

No randomized controlled trials have yet reported an individual patient benefit of initiating combination antiretroviral therapy (cART) at CD4 counts > 350 cells/μL. It is hypothesized that earlier initiation of cART in asymptomatic and otherwise healthy individuals may lead to poorer adherence and subsequently higher rates of resistance development.

Methods

In a large cohort of HIV‐positive individuals, we investigated the emergence of new resistance mutations upon virological treatment failure according to the CD4 count at the initiation of cART.

Results

Of 7918 included individuals, 6514 (82.3%), 996 (12.6%) and 408 (5.2%) started cART with a CD4 count ≤ 350, 351–499 and ≥ 500 cells/μL, respectively. Virological rebound occurred while on cART in 488 (7.5%), 46 (4.6%) and 30 (7.4%) with a baseline CD4 count ≤ 350, 351–499 and ≥ 500 cells/μL, respectively. Only four (13.0%) individuals with a baseline CD4 count > 350 cells/μL in receipt of a resistance test at viral load rebound were found to have developed new resistance mutations. This compared to 107 (41.2%) of those with virological failure who had initiated cART with a CD4 count < 350 cells/μL.

Conclusions

We found no evidence of increased rates of resistance development when cART was initiated at CD4 counts above 350 cells/μL.

Flaxseed oil supplementation alters the expression of inflammatory-related genes in dogs

Long chain n-3 fatty acids are beneficial to mammals because of their anti-inflammatory role. However, whether flaxseed oil, which is rich in short chain n-3 fatty acids, has such a role, it has not been extensively examined. This study investigated the supplementation of flaxseed oil on the regulation of genes involved in inflammatory responses such as heat shock proteins (HSP90 and HSP70) and interleukin (IL1β) in the white blood cells of dogs. Five beagles and 5 greyhounds were supplemented with Melrose(®) flaxseed oil at the rate of 100 mL/kg food for 21 days. The blood was collected at day 0, 15, and 22 following supplementation. The expression of 3 genes was quantified using real-time polymerase chain reaction. Plasma concentrations of fatty acids such as alpha linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, linoleic acid, and arachidonic acid were measured, and their correlations with changes in gene expression were determined. Flaxseed oil supplementation downregulated the expression of HSP90 and IL1βin greyhounds but showed no significant effect on these genes in beagles. HSP70 remained unchanged in both breeds following the supplementation. Correlations of HSP90 and IL1βexpression levels with the plasma fatty acid concentrations on day 22 showed a significant negative correlation in greyhounds. Dietary flaxseed oil altered the expression of genes involved in inflammation in white blood cells. Because the expression of the genes may vary in different breeds, it will be useful to consider breed responses to dietary manipulation in canine nutrition management.

Hormonal growth implants affect feed efficiency and expression of residual feed intake-associated genes in beef cattle

Hormonal growth promotants (HGP) have been used to improve feed conversion ratio (FCR) and growth rates of cattle by modifying protein turnover rates. Residual feed intake (RFI) is correlated with FCR and has been adopted in Australia as a measure of feed efficiency in cattle for the purpose of genetic improvement. Eight genes (AHSG, GHR, GSTM1, INHBA, PCDH19, S100A10, SERPINI2 and SOD3) have been previously reported to be highly associated with RFI and could potentially be used to predict RFI in bulls and steers. In this study, expression levels of these genes in liver tissue of 46 cattle were measured by quantitative real-time PCR. These cattle were part of a larger tenderness gene marker experiment consisting of two breeds (Angus and Brahman); two sexes (steers and heifers) and HGP treatments (implanted vs control). Cattle were measured for growth, feed efficiency, body composition and carcass traits. Results showed the expression of these eight genes was significantly correlated with RFI. However, HGP treatment did not affect RFI or the expression of the RFI-associated genes. HGP treatment increased average daily gain by 20%, improved FCR by 18%, and increased rib eye-muscle area by 7.5%. HGP treatment was effective in improving growth rate, presumably by its known action in the protein turnover mechanism. This mechanism has been hypothesised as one of the regulators of RFI. Lack of effect of HGP treatment on RFI does not support this hypothesis.

Expression of candidate genes for residual feed intake in Angus cattle

Residual feed intake (RFI) has been adopted in Australia for the purpose of genetic improvement in feed efficiency in beef cattle. RFI is the difference between the observed feed intake of an animal and the predicted feed intake based on its size and growth rate over a test period. Gene expression of eight candidate genes (AHSG, GHR, GSTM1, INHBA, PCDH19, S100A10, SERPINI2 and SOD3), previously identified as differentially expressed between divergent lines of high- and low-RFI animals, was measured in an unselected population of 60 steers from the Angus Society Elite Progeny Test Program using quantitative real-time PCR. Results showed that the levels of gene expression were significantly correlated with RFI. The genes explain around 33.2% of the phenotypic variance in RFI, and prediction equations using the expression data are reasonably accurate estimators of RFI. The association of these genes with economically important traits, such as other feed efficiency-related traits and fat, growth and carcass traits, was investigated as well. The expression of these candidate genes was significantly correlated with feed conversion ratio and daily feed intake, which are highly associated with RFI, suggesting a functional role for these genes in modulating feed utilisation. The expression of these genes did not show any association with average daily gain, eye muscle area and carcass composition.

Time-resolved characterization of the formation of a collisionless shock

We report on the temporally and spatially resolved detection of the precursory stages that lead to the formation of an unmagnetized, supercritical collisionless shock in a laser-driven laboratory experiment. The measured evolution of the electrostatic potential associated with the shock unveils the transition from a current free double layer into a symmetric shock structure, stabilized by ion reflection at the shock front. Supported by a matching particle-in-cell simulation and theoretical considerations, we suggest that this process is analogous to ion reflection at supercritical collisionless shocks in supernova remnants.

Ion acceleration in multispecies targets driven by intense laser radiation pressure

The acceleration of ions from ultrathin foils has been investigated by using 250 TW, subpicosecond laser pulses, focused to intensities of up to 3 × 10(20) W cm(-2). The ion spectra show the appearance of narrow-band features for protons and carbon ions peaked at higher energies (in the 5-10 MeV/nucleon range) and with significantly higher flux than previously reported. The spectral features and their scaling with laser and target parameters provide evidence of a multispecies scenario of radiation pressure acceleration in the light sail mode, as confirmed by analytical estimates and 2D particle-in-cell simulations. The scaling indicates that monoenergetic peaks with more than 100 MeV/nucleon are obtainable with moderate improvements of the target and laser characteristics, which are within reach of ongoing technical developments.

Effect of intranasal administration of Semliki Forest virus recombinant particles expressing interferon-β on the progression of experimental autoimmune encephalomyelitis

The effect of intranasal (IN) administration of Semliki Forest virus (SFV) recombinant particles expressing interferon-β [IFN-β, a partially effective treatment for multiple sclerosis (MS)] on the progression of experimental autoimmune encephalomyelitis (EAE, a murine model for MS) was investigated. The murine IFN-β gene was cloned from SFV-infected mouse brain by RT-PCR into an SFV-enhanced expression vector, pSFV10-E, from which IFN-β-expressing recombinant particles (rSFV10-E-IFN-β) were prepared. Expression studies using immunohistochemistry and viral inhibition assay in BHK and murine L929 cells confirmed increased expression of IFN-β. High level expression in the central nervous system (CNS) following IN inoculation was confirmed by the excision of olfactory bulbs, brain and spinal cord, and the detection of IFN-β levels in homogenised tissue by ELISA. rSFV10-E-IFN-β particles were administered IN to C57/Bl6 mice that had been induced for EAE using the encephalogenic peptide myelin oligodendrocyte glycoprotein (MOG) 35-55. The progression of EAE was measured by clinical score, weight loss and pathology. As previously shown, treatment with empty rSFV10-E particles moderately exacerbated EAE, as did continuous treatment with rSFV10-E-IFN-β particles. Inhibition of disease with rSFV10-E-IFN-β particles was dependent on the number and timing of treatments. Fewer treatments, administered before the effector stage, led to an improvement in clinical and pathology score. In conclusion, the timing and frequency of IN administration of rSFV10-E-IFN-β particles are critical to disease outcome, with treatment prior to the effector stage being most effective.

Weibel-induced filamentation during an ultrafast laser-driven plasma expansion

The development of current instabilities behind the front of a cylindrically expanding plasma has been investigated experimentally via proton probing techniques. A multitude of tubelike filamentary structures is observed to form behind the front of a plasma created by irradiating solid-density wire targets with a high-intensity (I ~ 10(19) W/cm(2)), picosecond-duration laser pulse. These filaments exhibit a remarkable degree of stability, persisting for several tens of picoseconds, and appear to be magnetized over a filament length corresponding to several filament radii. Particle-in-cell simulations indicate that their formation can be attributed to a Weibel instability driven by a thermal anisotropy of the electron population. We suggest that these results may have implications in astrophysical scenarios, particularly concerning the problem of the generation of strong, spatially extended and sustained magnetic fields in astrophysical jets.

Using gene expression information obtained by quantitative real-time PCR to evaluate Angus bulls divergently selected for feed efficiency

Residual feed intake (RFI) is a measure of feed efficiency in beef cattle. Young Angus bulls from lines of cattle divergently selected for RFI were used in a gene expression profiling study of the liver. Quantitative real-time PCR (qPCR) assay was used to quantify the differentially expressed genes and the information was used to examine the relationships between the genes and RFI and to classify the bulls into their respective RFI group. Gene expression of 21 genes in liver biopsies from 22 low RFI and 22 high RFI bulls were measured by qPCR. Gene expressions of 14 of the 21 genes were significantly correlated with RFI. The expression of the genes was used in a principal component analysis from which five components were extracted. The five principal components explained 70% of the variation in the dependency structure. The first component was highly correlated (correlation coefficient of 0.69) with RFI. The genes of the glutathione S-transferase Mu family (GSTM1, GSTM2, GSTM4), protocadherin 19 (PCDH19), ATP-binding cassette transporter C4 (ABCC4) and superoxide dismutase 3 (SOD3) are in the xenobiotic pathway and were the key factors in the first principal component. This highlights the important relationship between this pathway and variation in RFI. The second and third principal components were also correlated with RFI, with correlation coefficients of –0.28 and –0.20, respectively. Two of the four important genes of the second principal component work coordinately in the signalling pathways that inhibit the insulin-stimulated insulin receptor and regulate energy metabolism. This is consistent with the observation that a positive genetic correlation exists between RFI and fatness. The important genes in the third principal component are related to the extracellular matrix activity, with low RFI bulls showing high extracellular matrix activity.

Using genes differentially expressed in bulls to classify steers divergently selected for high and low residual feed intake

Feed efficiency is an economically important trait in livestock and residual feed intake (RFI) is a commonly used measure of the trait in beef cattle. Residual feed intake is the difference between the actual feed intake recorded over a test period and the expected feed intake of an animal based on its size and growth rate. It is a heritable trait, and efficient animals have lower RFI values. Several genes have been identified as being differentially expressed in the liver of Angus bulls that have been divergently selected for RFI. The objective of this study was to use genes that are differentially expressed in bulls to classify Angus steers from the same divergent RFI selection lines. Liver samples were collected at slaughter from 40 high RFI and 40 low RFI steers that were ~23 months old, and had just completed a 251-day feedlot feeding period. RNA samples from the livers were assayed by quantitative real-time PCR for 14 genes, which have been identified previously in bulls. Steers were not measured for RFI, hence the estimated breeding values (EBV) for RFI of their parents were used to calculate their mid-parent (average of the two parents) RFI-EBV. Correlation and discriminant analyses were conducted on the normalised quantitative real-time PCR data from the steers. Discriminant analysis was also conducted on the bull data for comparison. In the steers, 8 out of the 14 genes were significantly (P < 0.05) correlated with RFI-EBV. Two genes from the glutathione S-transferase mu family (GSTM1 and GSTM2) and the S100 calcium-binding protein A10 (S100A10) had the highest correlations with RFI-EBV, with correlation coefficients of 0.59, 0.44 and 0.36, respectively. Based on the 14 expressed genes, 84% of the steers and 98% of the bulls were correctly classified into their respective RFI selection lines. The results of this study indicate that a high proportion of the genes that were differentially expressed in the original study with bulls were also differentially expressed in this study with steers. The high accuracy in classification obtained in this study shows that the transcriptional approach to the study of the biological processes involved in variation in RFI has great potential for identification of candidate genes.

Implanon® failure in an HIV-positive woman on antiretroviral therapy resulting in two ectopic pregnancies

Since its introduction in 1999, Implanon® remains one of the preferred contraceptive choices for many women as it offers a highly effective means of long-term contraception for three years that does not rely on adherence. Like all hormonal contraceptives, certain hepatic enzyme-inducing drugs may reduce its efficacy. We present an interesting case of an HIV-positive woman on antiretroviral therapy having tubal pregnancies on two separate occasions with Implanon in place.

Early syphilis in a man with a negative Treponema pallidum enzyme immunoassay-IgM

Most serological tests for syphilis rely on an individual's ability to produce antibodies. A single screening test may be unreliable for screening in those with primary immunodeficiency. We present the first reported case of primary and secondary syphilis with negative Treponema pallidum enzyme immunoassay-IgM and Venereal Disease Research Laboratory tests in a man with common variable immunodeficiency.

Modified proton radiography arrangement for the detection of ultrafast field fronts

The experimental arrangement for the investigation of high-field laser-induced processes using a broadband proton probe beam has been modified to enable the detection of the ultrafast motion of field fronts. It is typical in such experiments for the target to be oriented perpendicularly with respect to the principal axis of the probe beam. It is demonstrated here, however, that the temporal imaging properties of the diagnostic arrangement are altered drastically by placing the axis (or plane) of the target at an oblique angle to the transverse plane of the probe beam. In particular, the detection of the motion of a laser-driven field front along a wire at a velocity of (0.95+/-0.05)c is described.

Transient high glycaemic intake in the last trimester of pregnancy increases offspring birthweight and postnatal growth rate in sheep: a randomised control trial

OBJECTIVE

Investigate the effect of transient hyperglycemic intake (analogous to snacking on high glycaemic foods) in the third trimester of pregnancy on offspring birthweight and subsequent growth in sheep.

DESIGN

Randomised trial.

SETTING

University research farm.

SAMPLE

Third trimester pregnant ewes.

METHODS

Ewes were blocked on weight, age and litter size and were randomly assigned to receive oral administration of 100 ml of propylene glycol (PG; n = 51) or 100 ml of water (control, C; n = 53) twice/day. Twice during treatment, 12 ewes from each group were selected and blood samples collected to determine the glucose and insulin response to treatment.

MAIN OUTCOME MEASURES

At birth, blood was collected from the lambs, their body dimensions measured and body weights recorded at 0, 6 and 12 weeks of age after which lambs were slaughtered when they reached 40 kg live weight.

RESULTS

Administration of PG elevated (P < 0.05) plasma glucose and insulin concentrations for 2 hours post administration compared with control ewes. Lambs (C: n = 80; PG: n = 70) born to ewes fed high glycaemic meals had higher birthweights (C: 5.01 +/- 0.18 kg; PG: 5.27 +/- 0.22 kg, P = 0.032), plasma glucose concentrations (P = 0.001) and ponderal index (weight/height(3), P = 0.043) and reached a similar (P > 0.05) slaughter carcass weight (C: 20.0 +/- 0.51 kg; PG: 20.6 +/- 0.55 kg) at an earlier age (PG: 166.0 +/- 13.2; C: 183.4 +/- 13.8 days, P = 0.039) compared with control lambs.

CONCLUSIONS

Transient high glycaemic intakes in the third trimester of pregnancy resulted in heavier offspring at birth that had faster growth rates in early postnatal life. This animal model is relevant for studying the relationship between maternal diet, fetal size and the risk of childhood obesity.

Laser-driven ultrafast field propagation on solid surfaces

The interaction of a 3x10;{19} W/cm;{2} laser pulse with a metallic wire has been investigated using proton radiography. The pulse is observed to drive the propagation of a highly transient field along the wire at the speed of light. Within a temporal window of 20 ps, the current driven by this field rises to its peak magnitude approximately 10;{4} A before decaying to below measurable levels. Supported by particle-in-cell simulation results and simple theoretical reasoning, the transient field measured is interpreted as a charge-neutralizing disturbance propagated away from the interaction region as a result of the permanent loss of a small fraction of the laser-accelerated hot electron population to vacuum.

Family meetings in palliative care: are they effective?

Despite the promotion of family meetings as an essential tool for information sharing and planning in palliative care, minimal evidence exists to show their effectiveness. We sought to rectify this gap in evidence-based practice by evaluating recently developed clinical guidelines for facilitating family meetings. Palliative care nurses were trained to conduct family meetings using the guidelines. To assess the effectiveness of the guidelines, primary family carers who attended a family meeting completed a self-report instrument to measure unmet needs at three time periods: immediately before the meeting (T1), immediately after the meeting (T2) and two days after the meeting (T3). Phone interviews with carers were also conducted at T3. Patients, health professionals and family meeting facilitators were also invited to complete an evaluation form at T2. A focus group was conducted at the end of the project to gain reflections from the family meeting facilitators about their role, re-evaluate the family meeting clinical guidelines and discuss barriers and facilitators for ongoing implementation. Twenty family meetings were conducted at St Vincent's Hospital (Melbourne, Australia). A total of 42 participants were involved, including 20 family carers, 4 patients and 18 health professionals. Family carers reported a statistically significant increase in having their care needs met, from T1 to T2, which was maintained at T3; they also reported that the meetings were useful. Health professionals and patients advised that the meetings were well facilitated. The results from this pilot study indicate that family meetings, conducted using specific clinical practice guidelines, were useful and effective. However, more research is required to confirm these findings. Strategies for implementation and further research are outlined.