Intranasal insulin administration decreases cerebral blood flow in cortico‐limbic regions: A neuropharmacological imaging study in normal and overweight males

Aim: To assess and compare the effects of 160 IU intranasal insulin (IN‐INS) administration on regional cerebral blood flow (rCBF) in healthy male individuals with normal weight and overweight phenotypes. / Methods: Thirty young male participants (mean age 25.9 years) were recruited and stratified into two cohorts based on body mass index: normal weight (18.5‐24.9 kg/m2) and overweight (25.0‐29.9 kg/m2). On separate mornings participants received 160 IU of IN‐INS using an intranasal protocol and intranasal placebo as part of a double‐blind crossover design. Thirty minutes following administration rCBF data were collected using a magnetic resonance imaging method called pseudocontinuous arterial spin labelling. Blood samples were collected to assess insulin sensitivity and changes over time in peripheral glucose, insulin and C‐peptide. / Results: Insulin sensitivity did not significantly differ between groups. Compared with placebo, IN‐INS administration reduced rCBF in parts of the hippocampus, insula, putamen, parahippocampal gyrus and fusiform gyrus in the overweight group. No effect was seen in the normal weight group. Insula rCBF was greater in the overweight group versus normal weight only under placebo conditions. Peripheral glucose and insulin levels were not affected by IN‐INS. C‐peptide levels in the normal weight group decreased significantly over time following IN‐INS administration but not placebo. / Conclusion: Insulin‐induced changes within key regions of the brain involved in gustation, memory and reward were observed in overweight healthy male individuals. Following placebo administration, differences in gustatory rCBF were observed between overweight and normal weight healthy individuals

Characterisation of nasal devices for delivery of insulin to the brain and evaluation in humans using functional magnetic resonance imaging

This study aimed to characterise three nasal drug delivery devices to evaluate their propensity to deliver human insulin solutions to the nasal cavity for redistribution to the central nervous system. Brain delivery was evaluated using functional magnetic resonance imaging to measure regional cerebral blood flow. Intranasal insulin administration has been hypothesised to exploit nose-to-brain pathways and deliver drug directly to the brain tissue whilst limiting systemic exposure. Three nasal pump-actuator configurations were compared for delivery of 400 IU/mL insulin solution by measuring droplet size distribution, plume geometry, spray pattern and in vitro deposition in a nasal cast. The device with optimal spray properties for nose to brain delivery (spray angle between 30° and 45°; droplet size between 20 and 50 μm) also favoured high posterior-superior deposition in the nasal cast and was utilised in a pharmacological magnetic resonance imaging study. Functional magnetic resonance imaging in healthy male volunteers showed statistically significant decreases in regional cerebral blood flow within areas dense in insulin receptors (bilateral amygdala) in response to intranasally administered insulin (160 IU) compared to saline (control). These changes correspond to the expected effects of insulin in the brain and were achieved using a simple nasal spray device and solution formulation. We recommend that a thorough characterisation of nasal delivery devices and qualitative/quantitative assessment of the administered dose is reported in all studies of nose to brain delivery so that responses can be evaluated with respect to posology and comparison between studies is facilitated

Leading Developmental Peer Observation of Teaching in Higher Education: Perspectives from Australia and England

Whilst peer observation of teaching is well established as a practice that can enhance teaching quality, the challenge to fully embed this practice in universities remains unresolved. This article analyses the perspectives of 18 university leaders (nine Australian and nine English) drawn from a range of school-based leaders to senior leaders of learning and teaching. Our study indicates that some of the challenges associated with leading such schemes can be mitigated through approaches to educational leadership that enact a respectful and collegiate ethos. This we suggest can support developmental academic engagement in peer observation for positive and lasting change

Suppression of grasshopper sound production by nitric oxide-releasing neurons of the central complex

The central complex of acridid grasshoppers integrates sensory information pertinent to reproduction-related acoustic communication. Activation of nitric oxide (NO)/cyclic GMP-signaling by injection of NO donors into the central complex of restrained Chorthippus biguttulus females suppresses muscarine-stimulated sound production. In contrast, sound production is released by aminoguanidine (AG)-mediated inhibition of nitric oxide synthase (NOS) in the central body, suggesting a basal release of NO that suppresses singing in this situation. Using anti-citrulline immunocytochemistry to detect recent NO production, subtypes of columnar neurons with somata located in the pars intercerebralis and tangential neurons with somata in the ventro-median protocerebrum were distinctly labeled. Their arborizations in the central body upper division overlap with expression patterns for NOS and with the site of injection where NO donors suppress sound production. Systemic application of AG increases the responsiveness of unrestrained females to male calling songs. Identical treatment with the NOS inhibitor that increased male song-stimulated sound production in females induced a marked reduction of citrulline accumulation in central complex columnar and tangential neurons. We conclude that behavioral situations that are unfavorable for sound production (like being restrained) activate NOS-expressing central body neurons to release NO and elevate the behavioral threshold for sound production in female grasshoppers

An optimized protocol for microarray validation by quantitative PCR using amplified amino allyl labeled RNA

<p>Abstract</p> <p>Background</p> <p>Validation of microarrays data by quantitative real-time PCR (qPCR) is often limited by the low amount of available RNA. This raised the possibility to perform validation experiments on the amplified amino allyl labeled RNA (AA-aRNA) leftover from microarrays. To test this possibility, we used an ongoing study of our laboratory aiming at identifying new biomarkers of graft rejection by the transcriptomic analysis of blood cells from brain-dead organ donors.</p> <p>Results</p> <p>qPCR for ACTB performed on AA-aRNA from 15 donors provided Cq values 8 cycles higher than when original RNA was used (P < 0.001), suggesting a strong inhibition of qPCR performed on AA-aRNA. When expression levels of 5 other genes were measured in AA-aRNA generated from a universal reference RNA, qPCR sensitivity and efficiency were decreased. This prevented the quantification of one low-abundant gene, which was readily quantified in un-amplified and un-labeled RNA. To overcome this limitation, we modified the reverse transcription (RT) protocol that generates cDNA from AA-aRNA as follows: addition of a denaturation step and 2-min incubation at room temperature to improve random primers annealing, a transcription initiation step to improve RT, and a final treatment with RNase H to degrade remaining RNA. Tested on universal reference AA-aRNA, these modifications provided a gain of 3.4 Cq (average from 5 genes, P < 0.001) and an increase of qPCR efficiency (from -1.96 to -2.88; P = 0.02). They also allowed for the detection of a low-abundant gene that was previously undetectable. Tested on AA-aRNA from 15 brain-dead organ donors, RT optimization provided a gain of 2.7 cycles (average from 7 genes, P = 0.004). Finally, qPCR results significantly correlated with microarrays.</p> <p>Conclusion</p> <p>We present here an optimized RT protocol for validation of microarrays by qPCR from AA-aRNA. This is particularly valuable in experiments where limited amount of RNA is available.</p

Reproductive Factors and Serum Uric Acid Levels in Females from the General Population: The KORA F4 Study

Hyperuricemia is associated with an increased risk of metabolic and cardiovascular diseases. There are pronounced sex differences in the levels of uric acid. It is largely unknown whether or not reproductive parameters which induce hormonal changes are responsible for this. We examined if there are associations between reproductive parameters and uric acid levels in a female population-based sample. In this cross-sectional analysis, data of 1530 women aged 32 to 81 years participating in the KORA F4 study, conducted between 2006 and 2008 in Southern Germany were used. Reproductive parameters were obtained by standardized interviews. Uric acid levels were tested by the uricase method. The whole study sample and stratified in pre- and postmenopausal women was analyzed. Menopausal status and earlier age at menarche were associated with higher serum uric acid levels (age-adjusted: p-values 0.003, <0.001 respectively; after multivariable adjustment, including BMI: p-values 0.002, 0.036). A history of oral contraceptive use showed an association with uric acid levels only after multivariable adjustment (p-value 0.009). Hot flushes showed an association with uric acid levels only after age-adjustment (p-value 0.038), but lost significance after adding other confounders. Other reproductive factors, including parity, current or ever use of hormone replacement therapy, current use of oral contraceptives, hysterectomy, bilateral oophorectomy, or depressive mood related to menopausal transition were not associated with uric acid levels. Postmenopausal status, earlier age at menarche and a history of oral contraceptive use were independently associated with higher serum uric acid concentrations in women from the general population. Further studies, especially longitudinal population-based studies investigating the relationship of female reproductive parameters with uric acid levels are necessary to confirm our findings

‘Caution! The Bread is Poisoned’: The Hong Kong Mass Poisoning of January 1857

This article examines the Hong Kong mass poisoning of 15 January 1857, in which bread from a Chinese bakery that supplied the colonial community was adulterated with arsenic. Even though there is a wealth of printed and manuscript documentation available many vital aspects of the poisoning remain unclear. What kind of incident was it: an act of terrorism and attempted mass murder, a war crime, a criminal conspiracy, an act of commercial sabotage, an accident or even an imagined or imaginary event? Throughout, our focus remains firmly fixed on the central act of the poisoning itself and on what it reveals about the precarious nature of early colonial Hong Kong. Interpretations have swarmed over the available ‘facts'. Equally ironic is what happened to the afterlife of how the event was understood. This article seeks to rescue the Hong Kong poisoning from being a freakish and isolated footnote of only local interest. Accepting this historical verdict would be a mistake as it is of significance not only at a local level, but geopolitically in Britain and across the empire

Genetic modifiers ameliorate endocytic and neuromuscular defects in a model of spinal muscular atrophy

© 2020 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.Background: Understanding the genetic modifiers of neurodegenerative diseases can provide insight into the mechanisms underlying these disorders. Here, we examine the relationship between the motor neuron disease spinal muscular atrophy (SMA), which is caused by reduced levels of the survival of motor neuron (SMN) protein, and the actin-bundling protein Plastin 3 (PLS3). Increased PLS3 levels suppress symptoms in a subset of SMA patients and ameliorate defects in SMA disease models, but the functional connection between PLS3 and SMN is poorly understood.Results: We provide immunohistochemical and biochemical evidence for large protein complexes localized in vertebrate motor neuron processes that contain PLS3, SMN and members of the hnRNP F/H family of proteins. Using a Caenorhabditis elegans (C. elegans) SMA model, we determine that overexpression of PLS3 or loss of the C. elegans hnRNP F/H ortholog SYM-2 enhances endocytic function and ameliorates neuromuscular defects caused by decreased SMN-1 levels. Furthermore, either increasing PLS3 or decreasing SYM-2 levels suppresses defects in a C. elegans ALS model.Conclusions: We propose that hnRNP F/H act in the same protein complex as PLS3 and SMN and that the function of this complex is critical for endocytic pathways, suggesting that hnRNP F/H proteins could be potential targets for therapy development.Peer reviewe

Transforming growth factor β receptor 1 is a new candidate prognostic biomarker after acute myocardial infarction

<p>Abstract</p> <p>Background</p> <p>Prediction of left ventricular (LV) remodeling after acute myocardial infarction (MI) is clinically important and would benefit from the discovery of new biomarkers.</p> <p>Methods</p> <p>Blood samples were obtained upon admission in patients with acute ST-elevation MI who underwent primary percutaneous coronary intervention. Messenger RNA was extracted from whole blood cells. LV function was evaluated by echocardiography at 4-months.</p> <p>Results</p> <p>In a test cohort of 32 MI patients, integrated analysis of microarrays with a network of protein-protein interactions identified subgroups of genes which predicted LV dysfunction (ejection fraction ≤ 40%) with areas under the receiver operating characteristic curve (AUC) above 0.80. Candidate genes included transforming growth factor beta receptor 1 (TGFBR1). In a validation cohort of 115 MI patients, TGBFR1 was up-regulated in patients with LV dysfunction (P < 0.001) and was associated with LV function at 4-months (P = 0.003). TGFBR1 predicted LV function with an AUC of 0.72, while peak levels of troponin T (TnT) provided an AUC of 0.64. Adding TGFBR1 to the prediction of TnT resulted in a net reclassification index of 8.2%. When added to a mixed clinical model including age, gender and time to reperfusion, TGFBR1 reclassified 17.7% of misclassified patients. TGFB1, the ligand of TGFBR1, was also up-regulated in patients with LV dysfunction (P = 0.004), was associated with LV function (P = 0.006), and provided an AUC of 0.66. In the rat MI model induced by permanent coronary ligation, the TGFB1-TGFBR1 axis was activated in the heart and correlated with the extent of remodeling at 2 months.</p> <p>Conclusions</p> <p>We identified TGFBR1 as a new candidate prognostic biomarker after acute MI.</p

A Unified Model of the GABA(A) Receptor Comprising Agonist and Benzodiazepine Binding Sites

We present a full-length α(1)β(2)γ(2) GABA receptor model optimized for agonists and benzodiazepine (BZD) allosteric modulators. We propose binding hypotheses for the agonists GABA, muscimol and THIP and for the allosteric modulator diazepam (DZP). The receptor model is primarily based on the glutamate-gated chloride channel (GluCl) from C. elegans and includes additional structural information from the prokaryotic ligand-gated ion channel ELIC in a few regions. Available mutational data of the binding sites are well explained by the model and the proposed ligand binding poses. We suggest a GABA binding mode similar to the binding mode of glutamate in the GluCl X-ray structure. Key interactions are predicted with residues α(1)R66, β(2)T202, α(1)T129, β(2)E155, β(2)Y205 and the backbone of β(2)S156. Muscimol is predicted to bind similarly, however, with minor differences rationalized with quantum mechanical energy calculations. Muscimol key interactions are predicted to be α(1)R66, β(2)T202, α(1)T129, β(2)E155, β(2)Y205 and β(2)F200. Furthermore, we argue that a water molecule could mediate further interactions between muscimol and the backbone of β(2)S156 and β(2)Y157. DZP is predicted to bind with interactions comparable to those of the agonists in the orthosteric site. The carbonyl group of DZP is predicted to interact with two threonines α(1)T206 and γ(2)T142, similar to the acidic moiety of GABA. The chlorine atom of DZP is placed near the important α(1)H101 and the N-methyl group near α(1)Y159, α(1)T206, and α(1)Y209. We present a binding mode of DZP in which the pending phenyl moiety of DZP is buried in the binding pocket and thus shielded from solvent exposure. Our full length GABA(A) receptor is made available as Model S1