Fetal Sex and RHD Genotyping with Digital PCR Demonstrates Greater Sensitivity than Real-time PCR.

BACKGROUND: Noninvasive genotyping of fetal RHD (Rh blood group, D antigen) can prevent the unnecessary administration of prophylactic anti-D to women carrying RHD-negative fetuses. We evaluated laboratory methods for such genotyping. METHODS: Blood samples were collected in EDTA tubes and Streck® Cell-Free DNA™ blood collection tubes (Streck BCTs) from RHD-negative women (n = 46). Using Y-specific and RHD-specific targets, we investigated variation in the cell-free fetal DNA (cffDNA) fraction and determined the sensitivity achieved for optimal and suboptimal samples with a novel Droplet Digital™ PCR (ddPCR) platform compared with real-time quantitative PCR (qPCR). RESULTS: The cffDNA fraction was significantly larger for samples collected in Streck BCTs compared with samples collected in EDTA tubes (P < 0.001). In samples expressing optimal cffDNA fractions (≥4%), both qPCR and digital PCR (dPCR) showed 100% sensitivity for the TSPY1 (testis-specific protein, Y-linked 1) and RHD7 (RHD exon 7) assays. Although dPCR also had 100% sensitivity for RHD5 (RHD exon 5), qPCR had reduced sensitivity (83%) for this target. For samples expressing suboptimal cffDNA fractions (<2%), dPCR achieved 100% sensitivity for all assays, whereas qPCR achieved 100% sensitivity only for the TSPY1 (multicopy target) assay. CONCLUSIONS: qPCR was not found to be an effective tool for RHD genotyping in suboptimal samples (<2% cffDNA). However, when testing the same suboptimal samples on the same day by dPCR, 100% sensitivity was achieved for both fetal sex determination and RHD genotyping. Use of dPCR for identification of fetal specific markers can reduce the occurrence of false-negative and inconclusive results, particularly when samples express high levels of background maternal cell-free DNA

P-rex1 cooperates with PDGFRβ to drive cellular migration in 3D microenvironments

Expression of the Rac-guanine nucleotide exchange factor (RacGEF), P-Rex1 is a key determinant of progression to metastasis in a number of human cancers. In accordance with this proposed role in cancer cell invasion and metastasis, we find that ectopic expression of P-Rex1 in an immortalised human fibroblast cell line is sufficient to drive multiple migratory and invasive phenotypes. The invasive phenotype is greatly enhanced by the presence of a gradient of serum or platelet-derived growth factor, and is dependent upon the expression of functional PDGF receptor β. Consistently, the invasiveness of WM852 melanoma cells, which endogenously express P-Rex1 and PDGFRβ, is opposed by siRNA of either of these proteins. Furthermore, the current model of P-Rex1 activation is advanced through demonstration of P-Rex1 and PDGFRβ as components of the same macromolecular complex. These data suggest that P-Rex1 has an influence on physiological migratory processes, such as invasion of cancer cells, both through effects upon classical Rac1-driven motility and a novel association with RTK signalling complexes

Auditory grouping occurs prior to intersensory pairing: evidence from temporal ventriloquism

The authors examined how principles of auditory grouping relate to intersensory pairing. Two sounds that normally enhance sensitivity on a visual temporal order judgement task (i.e. temporal ventriloquism) were embedded in a sequence of flanker sounds which either had the same or different frequency (Exp. 1), rhythm (Exp. 2), or location (Exp. 3). In all experiments, we found that temporal ventriloquism only occurred when the two capture sounds differed from the flankers, demonstrating that grouping of the sounds in the auditory stream took priority over intersensory pairing. By combining principles of auditory grouping with intersensory pairing, we demonstrate that capture sounds were, counter-intuitively, more effective when their locations differed from that of the lights rather than when they came from the same position as the lights

No effect of auditory–visual spatial disparity on temporal recalibration

It is known that the brain adaptively recalibrates itself to small (∼100 ms) auditory–visual (AV) temporal asynchronies so as to maintain intersensory temporal coherence. Here we explored whether spatial disparity between a sound and light affects AV temporal recalibration. Participants were exposed to a train of asynchronous AV stimulus pairs (sound-first or light-first) with sounds and lights emanating from either the same or a different location. Following a short exposure phase, participants were tested on an AV temporal order judgement (TOJ) task. Temporal recalibration manifested itself as a shift of subjective simultaneity in the direction of the adapted audiovisual lag. The shift was equally big when exposure and test stimuli were presented from the same or different locations. These results provide strong evidence for the idea that spatial co-localisation is not a necessary constraint for intersensory pairing to occur

A nurse-led, preventive, psychological intervention to reduce PTSD symptom severity in critically ill patients: the POPPI feasibility study and cluster RCT

BACKGROUND: High numbers of patients experience severe acute stress in critical care units. Acute stress has been linked to post-critical care psychological morbidity, including post-traumatic stress disorder (PTSD). Previously, a preventive, complex psychological intervention [Psychological Outcomes following a nurse-led Preventative Psychological Intervention for critically ill patients (POPPI)] was developed by this research team, to be led by nurses, to reduce the development of PTSD symptom severity at 6 months. OBJECTIVES: The objectives were to (1) standardise and refine the POPPI intervention, and, if feasible, (2) evaluate it in a cluster randomised clinical trial (RCT). DESIGN: Two designs were used – (1) two feasibility studies to test the delivery and acceptability (to patients and staff) of the intervention, education package and support tools, and to test the trial procedures (i.e. recruitment and retention), and (2) a multicentre, parallel-group, cluster RCT with a baseline period and staggered roll-out of the intervention. SETTING: This study was set in NHS adult, general critical care units. PARTICIPANTS: The participants were adult patients who were > 48 hours in a critical care unit, receiving level 3 care and able to consent. INTERVENTIONS: The intervention comprised three elements – (1) creating a therapeutic environment in critical care, (2) three stress support sessions for patients identified as acutely stressed and (3) a relaxation and recovery programme for patients identified as acutely stressed. MAIN OUTCOMES MEASURES: Primary outcome – patient-reported symptom severity using the PTSD Symptom Scale – Self Report (PSS-SR) questionnaire (to measure clinical effectiveness) and incremental costs, quality-adjusted life-years (QALYs) and net monetary benefit at 6 months (to measure cost-effectiveness). Secondary outcomes – days alive and free from sedation to day 30; duration of critical care unit stay; PSS-SR score of > 18 points; depression, anxiety and health-related quality of life at 6 months; and lifetime cost-effectiveness. RESULTS: (1) A total of 127 participants were recruited to the intervention feasibility study from two sites and 86 were recruited to the RCT procedures feasibility study from another two sites. The education package, support tools and intervention were refined. (2) A total of 24 sites were randomised to the intervention or control arms. A total of 1458 participants were recruited. Twelve sites delivered the intervention during the intervention period: > 80% of patients received two or more stress support sessions and all 12 sites achieved the target of > 80% of clinical staff completing the POPPI online training. There was, however, variation in delivery across sites. There was little difference between baseline and intervention periods in the development of PTSD symptom severity (measured by mean PSS-SR score) at 6 months for surviving patients in either the intervention or the control group: treatment effect estimate −0.03, 95% confidence interval (CI) −2.58 to 2.52; p = 0.98. On average, the intervention decreased costs and slightly improved QALYs, leading to a positive incremental net benefit at 6 months (£835, 95% CI −£4322 to £5992), but with considerable statistical uncertainty surrounding these results. There were no significant differences between the groups in any of the secondary outcomes or in the prespecified subgroup analyses. LIMITATIONS: There was a risk of bias because different consent processes were used and as a result of the lack of blinding, which was mitigated as far as possible within the study design. The intervention started later than anticipated. Patients were not routinely monitored for delirium. CONCLUSIONS: Among level 3 patients who stayed > 48 hours in critical care, the delivery of a preventive, complex psychological intervention, led by nurses, did not reduce the development of PTSD symptom severity at 6 months, when compared with usual care. FUTURE WORK: Prior to development and evaluation of subsequent psychological interventions, there is much to learn from post hoc analyses of the cluster RCT rich quantitative and qualitative data. TRIAL REGISTRATION: This trial is registered as ISRCTN61088114 and ISRCTN53448131. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 23, No. 30. See the NIHR Journals Library website for further project information

Abnormal cognition, sleep, EEG and brain metabolism in a novel knock-in Alzheimer mouse, PLB1

Peer reviewedPublisher PD

Convulsive liability of bupropion hydrochloride metabolites in Swiss albino mice

<p>Abstract</p> <p>Background</p> <p>It is known that following chronic dosing with bupropion HCl active metabolites are present in plasma at levels that are several times higher than that of the parent drug, but the possible convulsive effects of the major metabolites are not known.</p> <p>Methods</p> <p>We investigated the convulsive liability and dose-response of the three major bupropion metabolites following intraperitoneal administration of single doses in female Swiss albino mice, namely erythrohydrobupropion HCl, threohydrobupropion HCl, and hydroxybupropion HCl. We compared these to bupropion HCl. The actual doses of the metabolites administered to mice (n = 120; 10 per dose group) were equimolar equivalents of bupropion HCl 25, 50 and 75 mg/kg. Post treatment, all animals were observed continuously for 2 h during which the number, time of onset, duration and intensity of convulsions were recorded. The primary outcome variable was the percentage of mice in each group who had a convulsion at each dose. Other outcome measures were the time to onset of convulsions, mean convulsions per mouse, and the duration and intensity of convulsions.</p> <p>Results</p> <p>All metabolites were associated with a greater percentage of seizures compared to bupropion, but the percentage of convulsions differed between metabolites. Hydroxybupropion HCl treatment induced the largest percentage of convulsing mice (100% at both 50 and 75 mg/kg) followed by threohydrobupropion HCl (50% and 100%), and then erythrohydrobupropion HCl (10% and 90%), compared to bupropion HCl (0% and 10%). Probit analysis also revealed the dose-response curves were significantly different (p < 0.0001) with CD₅₀values of 35, 50, 61 and 82 mg/kg, respectively for the four different treatments. Cox proportional hazards model results showed that bupropion HCl, erythrohydrobupropion HCl, and threohydrobupropion HCl were significantly less likely to induce convulsions within the 2-h post treatment observation period compared to hydroxybupropion HCl. The mean convulsions per mouse also showed the same dose-dependent and metabolite-dependent trends.</p> <p>Conclusion</p> <p>The demonstration of the dose-dependent and metabolite-dependent convulsive effects of bupropion metabolites is a novelty.</p

Microencapsulated foods as a functional delivery vehicle for omega-3 fatty acids: a pilot study

It is well established that the ingestion of the omega-3 (N3) fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) positively benefit a variety of health indices. Despite these benefits the actual intake of fish derived N3 is relatively small in the United States. The primary aim of our study was to examine a technology capable of delivering omega-3 fatty acids in common foods via microencapsulation (MicroN3) in young, healthy, active participants who are at low risk for cardiovascular disease. Accordingly, we randomized 20 participants (25.4 ± 6.2 y; 73.4 ± 5.1 kg) to receive the double blind delivery of a placebo-matched breakfast meal (~2093 kJ) containing MicroN3 (450–550 mg EPA/DHA) during a 2-week pilot trial. Overall, we observed no differences in overall dietary macronutrient intake other than the N3 delivery during our treatment regimen. Post-test ANOVA analysis showed a significant elevation in mean (SE) plasma DHA (91.18 ± 9.3 vs. 125.58 ± 11.3 umol/L; P < 0.05) and a reduction in triacylglycerols (89.89 ± 12.8 vs. 80.78 ± 10.4 mg/dL; P < 0.05) accompanying the MicroN3 treatment that was significantly different from placebo (P < 0.05). In post study interviews, participants reported that the ingested food was well-tolerated, contained no fish taste, odor or gastrointestinal distress accompanying treatment. The use of MicroN3 foods provides a novel delivery system for the delivery of essential fatty acids. Our study demonstrates that MicroN3 foods promote the absorption of essential N3, demonstrate bioactivity within 2 weeks of ingestion and are well tolerated in young, active participants who are at low risk for cardiovascular disease