Allostatic load and mental health during COVID-19: The moderating role of neuroticism.

BACKGROUND: During the COVID-19 pandemic increased risk of poor mental health has been evident across different cultures and contexts. This study aims to examine whether allostatic load (AL) prior to the pandemic was predictive of poor mental health during the pandemic, and if any associations were moderated by neuroticism. METHODS: Data were extracted from Waves 2 (2011, allostatic load), 3 (2012, neuroticism), and the COVID-19 study (April 2020) of the Understanding Society database in the UK; data were available for 956 participants. RESULTS: Mental health increased from 2012- to during the pandemic. Neuroticism and AL were positively associated with poorer mental health during COVID-19, such that those who had scored higher on neuroticism and had higher AL prior to the pandemic reported poorer mental health during the pandemic. Neuroticism was also a significant moderator; the effect of AL on mental health during the pandemic was exacerbated in those with high and moderate levels of neuroticism but not lower. Moreover, this was driven by the immune-related indices of AL. This withstood adjustment for age, gender, employment status and prior mental health. These findings are discussed in relation to the pathophysiological mechanisms of mental health.

Arts on prescription: observed changes in anxiety, depression, and well-being across referral cycles.

OBJECTIVES: Arts on prescription (AoP) interventions are part of mainstream social prescribing provision in primary health care. Whilst the body of evidence for AoP interventions has been developing, this has primarily focused on well-being. STUDY DESIGN: The present work is an observational longitudinal study on a community-based AoP social prescribing intervention in the South West UK. METHOD: The present study assessed changes in anxiety, depression, and well-being in a cohort of patients participating in up to two eight-week cycles of AoP. The sample consisted of 245 individuals referred into the programme from 2017 to 2019, with a sub-sample of participants (N = 110) with identifiable multimorbidity. Outcomes were measured pre- and post-intervention at both initial and re-referral. RESULTS: Anxiety, depression, and well-being were all significantly improved after initial referral, re-referral, and overall from initial to post re-referral for this intervention in the whole sample and multimorbid sub-sample. Multivariate analyses revealed that no participant variables appeared to account for the variance in outcome change scores. CONCLUSION: The research provides further support for AoP interventions, finding associations with reduced anxiety and depression and increased well-being. Additionally, these outcomes are evidenced in those with multimorbidity, as well as across initial- and re-referral cycles.

Neural plasticity is modified over the human menstrual cycle: Combined insight from sensory evoked potential LTP and repetition suppression.

In healthy women, fluctuations in hormones including progesterone and oestradiol lead to functional changes in the brain over the course of each menstrual cycle. Though considerable attention has been directed towards understanding changes in human cognition over the menstrual cycle, changes in underlying processes such as neural plasticity have largely only been studied in animals. In this study we explored predictive coding and repetition suppression via the roving mismatch negativity paradigm as a model of short-term plasticity (Garrido, Kilner, Kiebel, et al., 2009), and Hebbian learning via visual sensory long-term potentiation (LTP) as a model of long-term plasticity (Teyler et al., 2005). Electroencephalography (EEG) was recorded in 20 females during their early follicular and mid-luteal phases. Event-related potential (ERP) analyses were complemented with dynamic causal modelling (DCM) to characterise changes in the underlying neural architecture. More sustained variability in the ERP response to a change in tone during the luteal phase are interpreted as a delayed habituation of the P3a component in the luteal relative to the follicular phase. The additional increased forward connection strength over tone repetitions compared to the follicular phase suggests that, in this phase, females may be less efficient when processing deviations from predicted sensory input (error). In contrast, there appears to be no reliable change in sensory LTP. This suggests that predictive coding, but not Hebbian plasticity is modified in the mid-luteal compared to the follicular phase, at least at the days of the menstrual cycle tested. This finding implicates the human menstrual cycle in complex changes in neural plasticity and provides further evidence for the importance of considering the menstrual cycle when including females in electrophysiological research.

Indexing sensory plasticity: Evidence for distinct Predictive Coding and Hebbian learning mechanisms in the cerebral cortex.

The Roving Mismatch Negativity (MMN), and Visual LTP paradigms are widely used as independent measures of sensory plasticity. However, the paradigms are built upon fundamentally different (and seemingly opposing) models of perceptual learning; namely, Predictive Coding (MMN) and Hebbian plasticity (LTP). The aim of the current study was to compare the generative mechanisms of the MMN and visual LTP, therefore assessing whether Predictive Coding and Hebbian mechanisms co-occur in the brain. Forty participants were presented with both paradigms during EEG recording. Consistent with Predictive Coding and Hebbian predictions, Dynamic Causal Modelling revealed that the generation of the MMN modulates forward and backward connections in the underlying network, while visual LTP only modulates forward connections. These results suggest that both Predictive Coding and Hebbian mechanisms are utilized by the brain under different task demands. This therefore indicates that both tasks provide unique insight into plasticity mechanisms, which has important implications for future studies of aberrant plasticity in clinical populations.

An fMRI investigation of the relationship between future imagination and cognitive flexibility.

While future imagination is largely considered to be a cognitive process grounded in default mode network activity, studies have shown that future imagination recruits regions in both default mode and frontoparietal control networks. In addition, it has recently been shown that the ability to imagine the future is associated with cognitive flexibility, and that tasks requiring cognitive flexibility result in increased coupling of the default mode network with frontoparietal control and salience networks. In the current study, we investigated the neural correlates underlying the association between cognitive flexibility and future imagination in two ways. First, we experimentally varied the degree of cognitive flexibility required during future imagination by manipulating the disparateness of episodic details contributing to imagined events. To this end, participants generated episodic details (persons, locations, objects) within three social spheres; during fMRI scanning they were presented with sets of three episodic details all taken from the same social sphere (Congruent condition) or different social spheres (Incongruent condition) and required to imagine a future event involving the three details. We predicted that, relative to the Congruent condition, future simulation in the Incongruent condition would be associated with increased activity in regions of the default mode, frontoparietal and salience networks. Second, we hypothesized that individual differences in cognitive flexibility, as measured by performance on the Alternate Uses Task, would correspond to individual differences in the brain regions recruited during future imagination. A task partial least squares (PLS) analysis showed that the Incongruent condition resulted in an increase in activity in regions in salience networks (e.g. the insula) but, contrary to our prediction, reduced activity in many regions of the default mode network (including the hippocampus). A subsequent functional connectivity (within-subject seed PLS) analysis showed that the insula exhibited increased coupling with default mode regions during the Incongruent condition. Finally, a behavioral PLS analysis showed that individual differences in cognitive flexibility were associated with differences in activity in a number of regions from frontoparietal, salience and default-mode networks during both future imagination conditions, further highlighting that the cognitive flexibility underlying future imagination is grounded in the complex interaction of regions in these networks.

The effect of pasteurization on trace elements in donor breast milk.

OBJECTIVE: Premature infants often receive pasteurized donor human milk when mothers are unable to provide their own milk. This study aims to establish the effect of the pasteurization process on a range of trace elements in donor milk. STUDY DESIGN: Breast milk was collected from 16 mothers donating to the milk bank at the Royal Brisbane and Women's Hospital. Samples were divided into pre- and post-pasteurization aliquots and were Holder pasteurized. Inductively coupled plasma mass spectrometry was used to analyze the trace elements zinc (Zn), copper (Cu), selenium (Se), manganese (Mn), iodine (I), iron (Fe), molybdenum (Mo) and bromine (Br). Differences in trace elements pre- and post-pasteurization were analyzed. RESULTS: No significant differences were found between the trace elements tested pre- and post-pasteurization, except for Fe (P<0.05). The median (interquartile range, 25 to 75%; µg l(-1)) of trace elements for pre- and post- pasteurization aliquots were-Zn: 1639 (888-4508), 1743 (878-4143), Cu: 360 (258-571), 367 (253-531), Se: 12.34 (11.73-17.60), 12.62 (11.94-16.64), Mn: (1.48 (1.01-1.75), 1.49 (1.11-1.75), I (153 (94-189), 158 (93-183), Fe (211 (171-277), 194 (153-253), Mo (1.46 (0.37-2.99), 1.42 (0.29-3.73) and Br (1066 (834-1443), 989 (902-1396). CONCLUSIONS: Pasteurization had minimal effect on several trace elements in donor breast milk but high levels of inter-donor variability of trace elements were observed. The observed decrease in the iron content of pasteurized donor milk is, however, unlikely to be clinically relevant.

Initiation of adult myelopoiesis can occur in the absence of c-Myb whereas subsequent development is strictly dependent on the transcription factor.

The c-Myb transcriptional regulator is crucial to the development and functioning of haemopoietic cells, so much so that mouse embryos homozygous for an inactivated c-myb allele die from anaemia at about day 15 of gestation. By analysing c-myb(-/-) chimaeras we show that no mature cells of any lymphoid or myeloid lineage can be detected in adult haemopoietic tissues. This demonstrates that the effects of c-myb ablation on haemopoiesis are cell autonomous and correlates with an absence in the c-myb(-/-) foetal liver of uni- and multilineage CFUs. Indeed, CFU assays performed on E8.5 yolk sac cells revealed that haemopoietic progenitors are already defective at this stage. However, although cells expressing high levels of c-Kit were absent, we could detect a high proportion of CD34+CD45+ cells in the c-myb(-/-) foetal liver. Examination of chimaeric embryos revealed that c-myb(-/-) donor-derived CD34+/Kit+ cells, representing committed definitive progenitors, initially populated the foetal liver, but are unable to expand like wild type progenitors. Our results showing no megakaryocytic CFUs and a reduction in the absolute numbers of megakaryocytes in the c-myb(-/-) foetal liver also refute early suggestions that megakaryopoiesis is unaffected by the absence of c-Myb.

Density and composition of microorganisms during long-term (418 day) growth of potato using biologically reclaimed nutrients from inedible plant biomass.

A study evaluating alternative methods for long term operation of biomass production systems was recently completed at the Kennedy Space Center (KSC). The 418-day study evaluated repeated batch versus mixed-aged production of potato grown on either standard 1/2-strength Hoagland's nutrient solution or solutions including nutrients recycled from inedible plant material. The long term effects of closure and recycling on microbial dynamics were evaluated by monitoring the microbial communities associated with various habitats within the plant growth system (i.e., plant roots, nutrient solution, biofilms within the hydroponic systems, atmosphere, and atmospheric condensate). Plate count methods were used to enumerate and characterize microorganisms. Microscopic staining methods were used to estunate total cell densities. The primary finding was that the density and composition of microbial communities associated with controlled environmental plant growth systems are stable during long term operation. Continuous production resulted in slightly greater stability. Nutrient recycling, despite the addition of soluble organic material from the waste processing system, did not significantly increase microbial density in any of the habitats.

Vasopressor and depressor actions of angiotensin in the anesthetized fowl.

Vasopressor and depressor properties of angiotensins (ANG) were characterized in the anesthetized, adult female chicken Gallus gallus. [Asp1,Val5,Ser9]ANG I and [Asp1,Val5]ANG II (native fowl angiotensins) increased blood pressure, and removal or replacement of the amino acid in position 1 decreased pressor potency. The pressor effect of [Asp1,Val5]ANG II was inhibited nearly completely with [Sar1,Ile8]ANG II (5 micrograms.kg-1.min-1) and partially with [Sar1,Thr8]ANG II, [Ile8]ANG III, and [Ile8]ANG I. Phenoxybenzamine, reserpine, or 6-hydroxydopamine reduced the pressor action to one-third. After administration of these compounds [Asp1,Val5]ANG II caused biphasic responses, a depressor followed by a small pressor response. [Sar1,Ile8]ANG II completely, and meclofenamate partially, blocked the depressor response, whereas propranolol, methysergide, vasopressin antagonists, or atropine did not. These results suggest that in fowl 1) the first (Asp) and eighth (Phe) amino acids are important for receptor binding and action, 2) vasopressor action of angiotensin may be primarily caused by release of catecholamines, and 3) angiotensin may exert depressor action possibly by acting directly on the vascular smooth muscle.

Herniation of mitral leaflets in the Ehlers-Danlos syndrome.

A 47 year old patient with the Ehlers-Danlos syndrome (hypermobility of the joints, hyperextensibility of the skin and atrophic cutaneous scars) was evaluated because of a mitral regurgitant murmur and paroxysmal atrial tachycardia. Angiocardiography and echocardiography demonstrated marked systolic herniation of the posterior leaflets of the mitral valve. An echocardiogram from the patient's daughter, who also had paroxysmal atrial tachycardia, revealed the same abnormality. Although a "floppy" valve is common in Marfan's syndrome, this report emphasizes that it may also occur in patients with other heritable disorders of connective tissue.