In vitro characterisation of cell-level neurophysiological diversity in the rostral nucleus reuniens of adult mice

PublishedThis is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.The nucleus reuniens (Re) is the largest of the midline thalamic nuclei. We have performed a detailed neurophysiological characterization of neurons in the rostral Re of brain slices prepared from adult male mice. At resting potential (−63.7 ± 0.6 mV), circa 90% of Re neurons fired action potentials, typically continuously at ∼8 Hz. Although Re neurons experience a significant spontaneous barrage of fast, amino-acid-mediate synaptic transmission, this was not predominantly responsible for spontaneous spiking as firing persisted in the presence of glutamate and GABA receptor antagonists. With resting potential preset to −80 mV −20 pA current injections revealed a mean input resistance of 615 MΩ and mean time constant of 38 ms. Following cessation of this stimulus a significant rebound potential was seen that was sometimes large enough to trigger a short burst of very high frequency (100–300 Hz) firing. In most cells short (2 ms), strong (2 nA) current injections elicited a single spike followed by a large afterdepolarizing potential (ADP) which, when suprathreshold, generated high frequency spiking. Similarly, in the majority of cells preset at −80 mV, 500 ms depolarizing current injections to cells led to a brief initial burst of very high frequency firing, although this was lost when cells were preset at −72 mV. Biophysical and pharmacological experiments indicate a prominent role for T-type Ca2+ channels in the high-frequency bursting of Re neurons. Finally, we describe a novel form of activity-dependent intrinsic plasticity that persistently eliminates the burst firing potential of Re neurons

Neurophysiological alterations in the nucleus reuniens of a mouse model of Alzheimer's disease.

This is the author accepted manuscriptRecently, increased neuronal activity in nucleus reuniens (Re) has been linked to hyperexcitability within hippocampal-thalamo-cortical networks in the J20 mouse model of amyloidopathy. Here in vitro whole-cell patch clamp recordings were used to compare old pathology-bearing J20 mice and wild-type controls to examine whether altered intrinsic electrophysiological properties could contribute to the amyloidopathy-associated Re hyperactivity. A greater proportion of Re neurons display hyperpolarized membrane potentials in J20 mice without changes to the incidence or frequency of spontaneous action potentials. Re neurons recorded from J20 mice did not exhibit increased action potential generation in response to depolarizing current stimuli but an increased propensity to rebound burst following hyperpolarizing current stimuli. Increased rebound firing did not appear to result from alterations to T-type Ca2+ channels. Finally, in J20 mice, there was an ~8% reduction in spike width, similar to what has been reported in CA1 pyramidal neurons from multiple amyloidopathy mice. We conclude that alterations to the intrinsic properties of Re neurons may contribute to hippocampal-thalmo-cortical hyperexcitability observed under pathological beta-amyloid load.Alzheimer´s Research UKEli Lilly and Company Limited (T/A Lilly

Inhibition of free radical generation and improved survival by protection of the hepatic microvascular endothelium by targeted erythrocytes in orthotopic rat liver transplantation

The capacity of specifically targeted erythrocytes to inhibit free radical—mediated injury to the endothelial cell after cold preservation, and improve liver function was studied in two experimental models: An isolated perfused rat liver (IPRL) system and syngeneic orthotopic rat liver transplantation. In the IPRL model, livers were preserved in University of Wisconsin solution for 24 h at 4°C. At the end of the preservation period, livers were flushed with lactated Ringer’s (control), immu- noerythrocytes (IES), or blank intact erythrocytes prior to warm reperfusion for 2 h using an assanguinous Krebs-Henseleit buffer. Production of superoxide (O2-) anion during warm reperfusion in the IES-treated liver was reduced by 65% as compared with controls (P<0.001) and by 74% (P<0.001) when compared with blank erythrocyte—treated livers. Endothelial cell preservation, as assessed by levels of purine nucleoside phos- phorylase (PNP), was much better in the IES-treated group (P<0.001) when compared with untreated livers. Hepatocellular preservation was markedly improved in the IES-treated livers. In the syngeneic liver transplantation model, livers were preserved in UW solution for 24 h at 4°C. Prior to implantation, livers were flushed with 5 ml of cold lactated Ringer’s or immunoerythrocytes. Survival after three weeks was 60% in the IES-treated group and 30% in the untreated group. Survival in the IES-treated group was not significantly different from a control (no preservation) group. IES-treated livers in both models demonstrated better endothelial cell integrity and ultimate liver function. IES treatment therefore appears to protect the hepatic microvascular endothelial cell from reperfusion injury and could prove to be an easy reproducible method of donor organ preparation after cold preservation. © 1990 by Williams & Wilkins

Another tool in the genome-wide association study arsenal: population-based detection of somatic gene conversion

The hunt for the genetic contributors to complex disease has used a number of strategies, resulting in the identification of variants associated with many of the common diseases affecting society. However most of the genetic variants detected to date are single nucleotide polymorphisms (SNPs) and copy number variants (CNVs) and fall far short of explaining the full genetic component of any given disease. An as yet untapped genomic mechanism is somatic gene conversion and deletion, which could be complicit in disease risk but has been challenging to detect in genome-wide datasets. In a recent publication in BMC Medicine by Kenneth Ross, the author uses existing datasets to look at somatic gene conversion and deletion in human disease. Here, we describe how Ross's recent efforts to detect such occurrences could impact the field going forward

The dynamics of methylammonium ions in hybrid organic-inorganic perovskite solar cells

Methylammonium lead iodide perovskite can make high-efficiency solar cells, which also show an unexplained photocurrent hysteresis dependent on the device-poling history. Here we report quasielastic neutron scattering measurements showing that dipolar CH3NH3+ ions reorientate between the faces, corners or edges of the pseudo-cubic lattice cages in CH3NH3PbI3 crystals with a room temperature residence time of ~14 ps. Free rotation, π-flips and ionic diffusion are ruled out within a 1–200-ps time window. Monte Carlo simulations of interacting CH3NH3+ dipoles realigning within a 3D lattice suggest that the scattering measurements may be explained by the stabilization of CH3NH3+ in either antiferroelectric or ferroelectric domains. Collective realignment of CH3NH3+ to screen a device’s built-in potential could reduce photovoltaic performance. However, we estimate the timescale for a domain wall to traverse a typical device to be ~0.1–1 ms, faster than most observed hysteresis

Association between pain intensity and depressive symptoms in community-dwelling adults: longitudinal findings from the Survey of Health, Ageing and Retirement in Europe (SHARE)

Purpose: To investigate the longitudinal associations between pain and depressive symptoms in adults. Methods: Prospective cohort study on data from 28,515 community-dwelling adults ≥ 50 years, free from depression at baseline (Wave 5), with follow-up in Wave 6 of the Survey of Health, Ageing and Retirement in Europe (SHARE). Significant depressive symptoms were defined by a EURO-D score ≥ 4. The longitudinal association between baseline pain intensity and significant depressive symptoms at follow-up was analysed using logistic regression models; odds ratios (ORs) and confidence intervals (CI) were calculated, adjusting for socio-demographic and clinical factors, physical inactivity, loneliness, mobility and functional impairments. Results: Mean age was 65.4 years (standard deviation 9.0, range 50–99); 14,360 (50.4%) participants were women. Mean follow-up was 23.4 (standard deviation 3.4) months. At baseline, 2803 (9.8%) participants reported mild pain, 5253 (18.4%) moderate pain and 1431 (5.0%) severe pain. At follow-up, 3868 (13.6%) participants—1451 (10.3%) men and 2417 (16.8%) women—reported significant depressive symptoms. After adjustment, mild, moderate and severe baseline pain, versus no pain, were associated with an increased likelihood of significant depressive symptoms at follow-up: ORs (95% CI) were 1.20 (1.06–1.35), 1.32 (1.20–1.46) and 1.39 (1.19–1.63), respectively. These associations were more pronounced in men compared to women, and consistent in participants aged 50–64 years, those without mobility or functional impairment, and those without loneliness at baseline. Conclusion: Higher baseline pain intensity was longitudinally associated with a greater risk of significant depressive symptoms at 2-year follow-up, in community-dwelling adults without baseline depression

Distinctive dendritic cell subsets expressing factor XIIIa, CD1a, CD1b and CD1c in mycosis fungoides and psoriasis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73825/1/j.1600-0560.1995.tb00742.x.pd

Beta bursting in the retrosplenial cortex is a neurophysiological correlate of environmental novelty which is disrupted in a mouse model of Alzheimer's disease

This is the author accepted manuscript. The final version is available from the Society for Neuroscience via the DOI in this recordThe retrosplenial cortex (RSC) plays a significant role in spatial learning and memory and is functionally disrupted in the early stages of Alzheimer's disease. In order to investigate neurophysiological correlates of spatial learning and memory in this region we employed in vivo electrophysiology in awake and freely moving male mice, comparing neural activity between wild-type and J20 mice, a transgenic model of Alzheimer's disease-associated amyloidopathy. To determine the response of the RSC to environmental novelty local field potentials were recorded while mice explored novel and familiar recording arenas. In familiar environments we detected short, phasic bursts of beta (20-30 Hz) oscillations (beta bursts) which arose at a low but steady rate. Exposure to a novel environment rapidly initiated a dramatic increase in the rate, size and duration of beta bursts. Additionally, theta-alpha/beta cross-frequency coupling was significantly higher during novelty, and spiking of neurons in the RSC was significantly enhanced during beta bursts. Finally, excessive beta bursting was seen in J20 mice, including increased beta bursting during novelty and familiarity, yet a loss of coupling between beta bursts and spiking activity. These findings support the concept that beta bursting may be responsible for the activation and reactivation of neuronal ensembles underpinning the formation and maintenance of cortical representations, and that disruptions to this activity in J20 mice may underlie cognitive impairments seen in these animals.SIGNIFICANCE STATEMENTThe retrosplenial cortex is thought to be involved in the formation, recall and consolidation of contextual memory. The discovery of bursts of beta oscillations in this region, which are associated with increased neuronal spiking and strongly upregulated while mice explore novel environments, provides a potential mechanism for the activation of neuronal ensembles, which may underlie the formation of cortical representations of context. Excessive beta bursting in the retrosplenial cortex of J20 mice, a mouse model of Alzheimer's disease, alongside the disassociation of beta bursting from neuronal spiking, may underlie spatial memory impairments previously shown in these mice. These findings introduce a novel neurophysiological correlate of spatial learning and memory, and a potentially new form of Alzheimer's disease related cortical dysfunction.University of ExeterJanssen PharmaceuticaAlzheimer’s Research U

The TW Hya Rosetta Stone Project IV: A Hydrocarbon-rich Disk Atmosphere

Connecting the composition of planet-forming disks with that of gas giant exoplanet atmospheres, in particular through C/O ratios, is one of the key goals of disk chemistry. Small hydrocarbons like C2H and C3H2 have been identified as tracers of C/O, as they form abundantly under high C/O conditions. We present resolved c–C3H2 observations from the TW Hya Rosetta Stone Project, a program designed to map the chemistry of common molecules at 15–20 au resolution in the TW Hya disk. Augmented by archival data, these observations comprise the most extensive multi-line set for disks of both ortho and para spin isomers spanning a wide range of energies, Eu = 29–97 K. We find the ortho-to-para ratio of c–C3H2 is consistent with 3 throughout extent of the emission, and the total abundance of both c–C3H2 isomers is (7.5–10) × 10−11 per H atom, or 1%–10% of the previously published C2H abundance in the same source. We find c–C3H2 comes from a layer near the surface that extends no deeper than z/r = 0.25. Our observations are consistent with substantial radial variation in gas-phase C/O in TW Hya, with a sharp increase outside ~30 au. Even if we are not directly tracing the midplane, if planets accrete from the surface via, e.g., meridional flows, then such a change should be imprinted on forming planets. Perhaps interestingly, the HR 8799 planetary system also shows an increasing gradient in its giant planets' atmospheric C/O ratios. While these stars are quite different, hydrocarbon rings in disks are common, and therefore our results are consistent with the young planets of HR 8799 still bearing the imprint of their parent disk's volatile chemistry

A systematic review on health resilience to economic crises

Background The health effects of recent economic crises differ markedly by population group. The objective of this systematic review is to examine evidence from longitudinal studies on factors influencing resilience for any health outcome or health behaviour among the general population living in countries exposed to financial crises. Methods We systematically reviewed studies from six electronic databases (EMBASE, Global Health, MEDLINE, PsycINFO, Scopus, Web of Science) which used quantitative longitudinal study designs and included: (i) exposure to an economic crisis; (ii) changes in health outcomes/behaviours over time; (iii) statistical tests of associations of health risk and/or protective factors with health outcomes/behaviours. The quality of the selected studies was appraised using the Quality Assessment Tool for Quantitative Studies. PRISMA reporting guidelines were followed. Results From 14,584 retrieved records, 22 studies met the eligibility criteria. These studies were conducted across 10 countries in Asia, Europe and North America over the past two decades. Ten socio-demographic factors that increased or protected against health risk were identified: gender, age, education, marital status, household size, employment/occupation, income/ financial constraints, personal beliefs, health status, area of residence, and social relations. These studies addressed physical health, mortality, suicide and suicide attempts, mental health, and health behaviours. Women’s mental health appeared more susceptible to crises than men’s. Lower income levels were associated with greater increases in cardiovascular disease, mortality and worse mental health. Employment status was associated with changes in mental health. Associations with age, marital status, and education were less consistent, although higher education was associated with healthier behaviours. Conclusions Despite widespread rhetoric about the importance of resilience, there was a dearth of studies which operationalised resilience factors. Future conceptual and empirical research is needed to develop the epidemiology of resilience