Treatment with the vascular endothelial growth factor-A antibody, bevacizumab, has sex-specific effects in a rat model of mild traumatic brain injury

Mild traumatic brain injury (mTBI) involves damage to the cerebrovascular system. Vascular endothelial growth factor-A (VEGF-A) is an important modulator of vascular health and VEGF-A promotes the brain's ability to recover after more severe forms of brain injury; however, the role of VEGF-A in mTBI remains poorly understood. Bevacizumab (BEV) is a monoclonal antibody that binds to VEGF-A and neutralises its actions. To better understand the role of VEGF-A in mTBI recovery, this study examined how BEV treatment affected outcomes in rats given a mTBI. Adult Sprague-Dawley rats were assigned to sham-injury + vehicle treatment (VEH), sham-injury + BEV treatment, mTBI + VEH treatment, mTBI + BEV treatment groups. Treatment was administered intracerebroventricularly via a cannula beginning at the time of injury and continuing until the end of the study. Rats underwent behavioral testing after injury and were euthanized on day 11. In both females and males, BEV had a negative impact on cognitive function. mTBI and BEV treatment increased the expression of inflammatory markers in females. In males, BEV treatment altered markers related to hypoxia and vascular health. These novel findings of sex-specific responses to BEV and mTBI provide important insights into the role of VEGF-A in mTBI.

Measurements of Arterial Occlusion Pressure Using Hand-Held Devices

ABSTRACT

Vehrs, PR, Reynolds, S, Allen, J, Barrett, R, Blazzard, C, Burbank, T, Hart, H, Kasper, N, Lacey, R, Lopez, D, and Fellingham, GW. Measurements of arterial occlusion pressure using hand-held devices. J Strength Cond Res XX(X): 000-000, 2023-Arterial occlusion pressure (AOP) of the brachial artery was measured simultaneously using Doppler ultrasound (US), a hand-held Doppler (HHDOP), and a pulse oximeter (PO) in the dominant (DOM) and nondominant (NDOM) arms of males (n = 21) and females (n = 23) using continuous (CONT) and incremental (INCR) cuff inflation protocols. A mixed-model analysis of variance revealed significant (p < 0.05) overall main effects between AOP measured using a CONT (115.7 ± 10.9) or INCR (115.0 ± 11.5) cuff inflation protocol; between AOP measured using US (116.3 ± 11.2), HHDOP (115.4 ± 11.2), and PO (114.4 ± 11.2); and between males (120.7 ± 10.6) and females (110.5 ± 9.4). The small overall difference (1.81 ± 3.3) between US and PO measures of AOP was significant (p < 0.05), but the differences between US and HHDOP and between HHDOP and PO measures of AOP were not significant. There were no overall differences in AOP between the DOM and NDOM arms. Trial-to-trial variance in US measurements of AOP was not significant when using either cuff inflation protocol but was significant when using HHDOP and PO and a CONT cuff inflation protocol. Bland-Altman plots revealed reasonable limits of agreement for both HHDOP and PO measures of AOP. The small differences in US, HHDOP, and PO measurements of AOP when using CONT or INCR cuff inflation protocols are of minimal practical importance. The choice of cuff inflation protocol is one of personal preference. Hand-held Doppler of PO can be used to assess AOP before using blood flow restriction during exercise.

Psychedelics for acquired brain injury: a review of molecular mechanisms and therapeutic potential

Acquired brain injury (ABI), such as traumatic brain injury and stroke, is a leading cause of disability worldwide, resulting in debilitating acute and chronic symptoms, as well as an increased risk of developing neurological and neurodegenerative disorders. These symptoms can stem from various neurophysiological insults, including neuroinflammation, oxidative stress, imbalances in neurotransmission, and impaired neuroplasticity. Despite advancements in medical technology and treatment interventions, managing ABI remains a significant challenge. Emerging evidence suggests that psychedelics may rapidly improve neurobehavioral outcomes in patients with various disorders that share physiological similarities with ABI. However, research specifically focussed on psychedelics for ABI is limited. This narrative literature review explores the neurochemical properties of psychedelics as a therapeutic intervention for ABI, with a focus on serotonin receptors, sigma-1 receptors, and neurotrophic signalling associated with neuroprotection, neuroplasticity, and neuroinflammation. The promotion of neuronal growth, cell survival, and anti-inflammatory properties exhibited by psychedelics strongly supports their potential benefit in managing ABI. Further research and translational efforts are required to elucidate their therapeutic mechanisms of action and to evaluate their effectiveness in treating the acute and chronic phases of ABI.

New Collaborative Research on Suicide Prevention, Practice, and Policy With American Indian and Alaska Native Communities Holds Promise for All Peoples

Youth suicide is increasing in the United States, with deaths among younger people of color driving this upward trend. For more than four decades, American Indian and Alaska Native (AIAN) communities have suffered disproportionate rates of youth suicide and years of productive life lost compared to other U.S. Races. The National Institute of Mental Health (NIMH) recently funded three regional Collaborative Hubs to carry out suicide prevention research, practice, and policy development with AIAN communities in Alaska and rural and urban areas of the Southwestern United States. The Hub partnerships are supporting a diverse array of tribally-driven studies, approaches, and policies with immediate value for increasing empirically driven public health strategies to address youth suicide. We discuss unique features of the cross-Hub work, including: (a) long-standing Community-Based Participatory Research processes that led to the Hubs' innovative designs and novel approaches to suicide prevention and evaluation, (b) comprehensive ecological theoretical approaches that contextualize individual risk and protective factors in multilevel social contexts; (c) unique task-shifting and systems of care approaches to increase reach and impact on youth suicide in low-resource settings; and (d) prioritization of strengths-based approaches. The work of the Collaborative Hubs for AIAN youth suicide prevention is generating specific and substantive implications for practice, policy, and research presented in this article at a time when youth suicide prevention is a dire national priority. Approaches also have relevance for historically marginalized communities worldwide.

Effect of trans-cinnamaldehyde nanoemulsion wash on chicken embryo development in fertilized eggs

Cleanliness of eggs is critical in successful hatching egg operations. The objective of this study was to investigate the effect of trans-cinnamaldehyde nanoemulsion (TCNE) wash treatments, as a sanitation strategy, on embryonic development in fertilized eggs. Trans-cinnamaldehyde is a generally recognized as safe status phytochemical obtained from cinnamon bark. TCNE were prepared with emulsifiers Tween 80 (Tw.80) or gum Arabic and lecithin (GAL) by sonication. Day-old fertilized eggs were subjected to TCNE wash treatments at 34°C for 5 min, followed by 18 d of incubation at 37.7°C. Washing of fertilized eggs with TCNE-Tw.80 or GAL at 0.48% concentration did not significantly alter the egg weight at d 18 of incubation, as compared to baseline and control (P > 0.05). The egg weight loss (calculated as percentage) did not differ significantly between eggs subjected to nanoemulsion wash treatments and control eggs (P > 0.05). In case of embryo fertility and mortality, for baseline and control, ∼ 95% fertility rate was achieved, with combined early and midterm mortality at 16%. Likewise, TCNE-Tw.80 or TCNE-GAL resulted in 95% fertility (P > 0.05), with 11% and 17% combined early and midterm mortality, respectively. Furthermore, TCNE wash treatments did not differ significantly in yolk sac and embryo weight (as compared to control) and did not affect the length of the d 18 embryo (P > 0.05). Moreover, TCNE wash treatments did not alter tibia weight and length (P > 0.05). Results suggest that TCNE could potentially be used as a natural antimicrobial for fertilized egg sanitation. Further studies in industry settings are warranted.

Reelin Rescues Behavioral, Electrophysiological, and Molecular Metrics of a Chronic Stress Phenotype in a Similar Manner to Ketamine

Over the past decade, ketamine, an NMDA receptor antagonist, has demonstrated fast-acting antidepressant effects previously unseen with monoaminergic-based therapeutics. Concerns regarding psychotomimetic effects limit the use of ketamine for certain patient populations. Reelin, an extracellular matrix glycoprotein, has shown promise as a putative fast-acting antidepressant in a model of chronic stress. However, research has not yet demonstrated the changes that occur rapidly after peripheral reelin administration. To address this key gap in knowledge, male Long-Evans rats underwent a chronic corticosterone (CORT; or vehicle) paradigm (40 mg/kg, 21 d). On day 21, rats were then administered an acute dose of ketamine (10 mg/kg, i.p.), reelin (3 µg, i.v.), or vehicle. Twenty-four hours after administration, rats underwent behavioral or in vivo electrophysiological testing before killing. Immunohistochemistry was used to confirm changes in hippocampal reelin immunoreactivity. Lastly, the hippocampus was microdissected from fresh tissue to ascertain whole cell and synaptic-specific changes in protein expression through Western blotting. Chronic corticosterone induced a chronic stress phenotype in the forced swim test and sucrose preference test (SPT). Both reelin and ketamine rescued immobility and swimming, however reelin alone rescued latency to immobility. In vivo electrophysiology revealed decreases in hippocampal long-term potentiation (LTP) after chronic stress which was increased significantly by both ketamine and reelin. Reelin immunoreactivity in the dentate gyrus paralleled the behavioral and electrophysiological findings, but no significant changes were observed in synaptic-level protein expression. This exploratory research supports the putative rapid-acting antidepressant effects of an acute dose of reelin across behavioral, electrophysiological, and molecular measures.

Acute effects of single and repeated mild traumatic brain injury on levels of neurometabolites, lipids, and mitochondrial function in male rats

Introduction

Mild traumatic brain injuries (mTBIs) are the most common form of acquired brain injury. Symptoms of mTBI are thought to be associated with a neuropathological cascade, potentially involving the dysregulation of neurometabolites, lipids, and mitochondrial bioenergetics. Such alterations may play a role in the period of enhanced vulnerability that occurs after mTBI, such that a second mTBI will exacerbate neuropathology. However, it is unclear whether mTBI-induced alterations in neurometabolites and lipids that are involved in energy metabolism and other important cellular functions are exacerbated by repeat mTBI, and if such alterations are associated with mitochondrial dysfunction.

Methods

In this experiment, using a well-established awake-closed head injury (ACHI) paradigm to model mTBI, male rats were subjected to a single injury, or five injuries delivered 1 day apart, and injuries were confirmed with a beam-walk task and a video observation protocol. Abundance of several neurometabolites was evaluated 24 h post-final injury in the ipsilateral and contralateral hippocampus using in vivo proton magnetic resonance spectroscopy (1H-MRS), and mitochondrial bioenergetics were evaluated 30 h post-final injury, or at 24 h in place of 1H-MRS, in the rostral half of the ipsilateral hippocampus. Lipidomic evaluations were conducted in the ipsilateral hippocampus and cortex.

Results

We found that behavioral deficits in the beam task persisted 1- and 4 h after the final injury in rats that received repetitive mTBIs, and this was paralleled by an increase and decrease in hippocampal glutamine and glucose, respectively, whereas a single mTBI had no effect on sensorimotor and metabolic measurements. No group differences were observed in lipid levels and mitochondrial bioenergetics in the hippocampus, although some lipids were altered in the cortex after repeated mTBI.

Discussion

The decrease in performance in sensorimotor tests and the presence of more neurometabolic and lipidomic abnormalities, after repeated but not singular mTBI, indicates that multiple concussions in short succession can have cumulative effects. Further preclinical research efforts are required to understand the underlying mechanisms that drive these alterations to establish biomarkers and inform treatment strategies to improve patient outcomes.

First Direct Measurement Constraining the ^{34}Ar(α,p)^{37}K Reaction Cross Section for Mixed Hydrogen and Helium Burning in Accreting Neutron Stars

The rate of the final step in the astrophysical αp process, the ^{34}Ar(α,p)^{37}K reaction, suffers from large uncertainties due to a lack of experimental data, despite having a considerable impact on the observable light curves of x-ray bursts and the composition of the ashes of hydrogen and helium burning on accreting neutron stars. We present the first direct measurement constraining the ^{34}Ar(α,p)^{37}K reaction cross section, using the Jet Experiments in Nuclear Structure and Astrophysics gas jet target. The combined cross section for the ^{34}Ar,Cl(α,p)^{37}K,Ar reaction is found to agree well with Hauser-Feshbach predictions. The ^{34}Ar(α,2p)^{36}Ar cross section, which can be exclusively attributed to the ^{34}Ar beam component, also agrees to within the typical uncertainties quoted for statistical models. This indicates the applicability of the statistical model for predicting astrophysical (α,p) reaction rates in this part of the αp process, in contrast to earlier findings from indirect reaction studies indicating orders-of-magnitude discrepancies. This removes a significant uncertainty in models of hydrogen and helium burning on accreting neutron stars.

Intravenous Reelin Treatment Rescues Atrophy of Spleen White Pulp and Correlates to Rescue of Forced Swim Test Immobility and Neurochemical Alterations Induced by Chronic Stress

Reelin, an extracellular matrix protein with putative antidepressant-like properties, becomes dysregulated by chronic stress. Improvement in cognitive dysfunction and depression-like behavior induced by chronic stress has been reported with both intrahippocampal and intravenous Reelin treatment but the mechanisms responsible are not clear. To determine if treatment with Reelin modifies chronic stress-induced dysfunction in immune organs and whether this relates to behavioral and/or neurochemical outcomes, spleens were collected from both male (n = 62) and female (n = 53) rats treated with daily corticosterone injections for three weeks that received Reelin or vehicle. Reelin was intravenously administered once on the final day of chronic stress, or repeatedly, with weekly treatments throughout chronic stress. Behavior was assessed during the forced swim test and the object-in-place test. Chronic corticosterone caused significant atrophy of the spleen white pulp, but treatment with a single shot of Reelin restored white pulp in both males and females. Repeated Reelin injections also resolved atrophy in females. Correlations were observed between recovery of white pulp atrophy and recovery of behavioral deficits and expression of both Reelin and glutamate receptor 1 in the hippocampus, supporting a role of the peripheral immune system in the recovery of chronic stress-induced behaviors following treatment with Reelin. Our data adds to research indicating Reelin could be a valuable therapeutic target for chronic stress-related disorders including major depression.

Ketamine and serotonergic psychedelics: An update on the mechanisms and biosignatures underlying rapid-acting antidepressant treatment

The discovery of ketamine as a rapid-acting antidepressant spurred significant research to understand its underlying mechanisms of action and to identify other novel compounds that may act similarly. Serotonergic psychedelics (SPs) have shown initial promise in treating depression, though the challenge of conducting randomized controlled trials with SPs and the necessity of long-term clinical observation are important limitations. This review summarizes the similarities and differences between the psychoactive effects associated with both ketamine and SPs and the mechanisms of action of these compounds, with a focus on the monoaminergic, glutamatergic, gamma-aminobutyric acid (GABA)-ergic, opioid, and inflammatory systems. Both molecular and neuroimaging aspects are considered. While their main mechanisms of action differ-SPs increase serotonergic signaling while ketamine is a glutamatergic modulator-evidence suggests that the downstream mechanisms of action of both ketamine and SPs include mechanistic target of rapamycin complex 1 (mTORC1) signaling and downstream GABAA receptor activity. The similarities in downstream mechanisms may explain why ketamine, and potentially SPs, exert rapid-acting antidepressant effects. However, research on SPs is still in its infancy compared to the ongoing research that has been conducted with ketamine. For both therapeutics, issues with regulation and proper controls should be addressed before more widespread implementation. This article is part of the Special Issue on "Ketamine and its Metabolites".

Trans-cinnamaldehyde nanoemulsion wash inactivates Salmonella Enteritidis on shelled eggs without affecting egg color

Salmonella Enteritidis is a major foodborne pathogen that causes enteric illnesses in humans, primarily through the consumption of contaminated poultry meat and eggs. Despite implementation of traditional disinfection approaches to reduce S. Enteritidis contamination, egg-borne outbreaks continue to occur, raising public health concerns and adversely affecting the popularity and profitability for the poultry industry. Generally Recognized as Safe (GRAS) status phytochemicals such as Trans-cinnamaldehyde (TC) have previously shown to exhibit anti-Salmonella efficacy, however, the low solubility of TC is a major hurdle in its adoption as an egg wash treatment. Therefore, the present study investigated the efficacy of Trans-cinnamaldehyde nanoemulsions (TCNE) prepared with emulsifiers Tween 80 (Tw.80) or Gum Arabic and lecithin (GAL) as dip treatments, at 34°C, for reducing S. Enteritidis on shelled eggs in presence or absence of 5% chicken litter. In addition, the efficacy of TCNE dip treatments in reducing trans-shell migration of S. Enteritidis across shell barrier was investigated. The effect of wash treatments on shell color were evaluated on d 0, 1, 7, and 14 of refrigerated storage. TCNE-Tw.80 or GAL treatments (0.06, 0.12, 0.24, 0.48%) were effective in inactivating S. Enteritidis by at least 2 to 2.5 log cfu/egg as early as 1 min of washing time (P < 0.05). In presence of organic matter, nanoemulsions (0.48%) reduced S. Enteritidis counts by ∼ 2 to 2.5 log cfu/egg as early as 1 min, (P < 0.05). Nanoemulsion wash also inhibited trans-shell migration of S. Enteritidis, as compared to control (P < 0.05). The nanoemulsion wash treatments did not affect shell color (P > 0.05). Results suggest that TCNE could potentially be used as an antimicrobial wash to reduce S. Enteritidis on shelled eggs, although further studies investigating the effect of TCNE wash treatments on organoleptic properties of eggs are necessary.

Sex differences in basal reelin levels in the paraventricular hypothalamus and in response to chronic stress induced by repeated corticosterone in rats

Repeated exposure to the stress hormone corticosterone results in depressive-like behaviours paralleled by the downregulation of hippocampal reelin expression. Reelin is expressed in key neural populations involved in the stress response, but whether its hypothalamic expression is sex-specific or involved in sex-specific vulnerability to stress is unknown. Female and male rats were treated with either daily vehicle or corticosterone injections (40 mg/kg) for 21 days. Thereafter, they were subjected to several behavioural tasks before being sacrificed to allow the analysis of reelin expression in hypothalamic nuclei. The basal density of reelin-positive cells in males was significantly higher in the paraventricular nucleus (19 %) and in the medial preoptic area (51 %) compared to females. Chronic corticosterone injections increased the immobility time in the forced swim test in males (107 %) and females (108 %) and decreased the exploration of the elevated plus maze in males (34 %). Corticosterone also caused a significant decrease in the density of reelin-positive cells in males, in both ventrodorsal (37 %) and ventrolateral (32 %) subdivisions of the paraventricular nucleus, while not affecting females. Moreover, in the paraventricular nucleus of males, 30 % of the basal reelin-positive cells co-expressed oxytocin while only 17.5 % did in females, showing a positive correlation between reelin and oxytocin levels. Chronic corticosterone did not significantly affect co-localization levels. For the first time, this study shows that there is a sexually dimorphic subpopulation of reelin-positive neurons in the paraventricular nucleus that can be differentially affected by chronic stress.

Waning of SARS-CoV-2 IgG antibodies after vaccination: first results from the CoMoLo follow-up 2021

Background

In 2020, the study “Corona-Monitoring Lokal” (CoMoLo) assessed seroprevalences of SARS-CoV-2 IgG antibodies in four study locations that were particularly affected by outbreaks in the early stages of the pandemic in Germany. One of the objectives of the 2021 follow-up was to examine the development of immunological parameters over time, including the extent of IgG antibody waning after vaccination.

Methods

Venous blood specimens were collected from a sample of initial study participants over a 2-week period between May and October 2021, with an oversampling of seropositive or previously infected individuals. Levels of IgG antibodies to the SARS-CoV-2 spike protein were measured from serum using Anti-SARS-CoV-2-QuantiVac-ELISA (IgG) tests by Euroimmun. Information on SARS-CoV-2 vaccinations or known infections was collected via online questionnaires or telephone interviews.

Results

A total of 3328 participants (74% response) gave blood specimens for this follow-up study, with questionnaire information available for 2843 (85%) of these. Preliminary analyses suggest that in participants who had received two doses of a vaccine more than 3 weeks before giving blood (n = 1583), IgG levels decreased exponentially by about 9.8% (95%CI 9.1% - 10.4%) with each additional week since the last dose, when controlling for age, sex, and type of vaccine. There was evidence of this waning effect differing by vaccine type. Antibody levels also appear to decline with increasing age, according to preliminary results. Final results of the linear model used to assess the dynamics and predictive factors of antibody levels will be reported.

Conclusions

This follow-up study will add evidence to an improved understanding of antibody waning after SARS-CoV-2 vaccination. Preliminary results are in line with international studies and may be helpful for discussions on potential benefits of further vaccinations in Germany.

Key messages

• Antibodies induced by COVID-19 vaccination wane over time. The magnitude of this effect differs by vaccine type. Antibodies also decreased with increasing age.

• Our results may be helpful for discussions on potential benefits of further COVID-19 vaccinations in Germany.

International Horizon Scanning the impact of Covid-19 on increasing the health gap and vulnerability

 

The COVID-19 pandemic has caused unprecedented challenges for populations, health systems and governments worldwide, which have resulted in lasting economic, social and health impacts. The results of such have been felt disproportionately throughout society and existing vulnerabilities have been highlighted and heightened. A clear understanding of the extent of these vulnerabilities is needed in order to fully address the problem. The World Health Organization Collaborating Centre on Investment for Health and Well-being (WHOCC), Public Health Wales has developed a summary report focusing on the existing and emerging inequalities resulting from the pandemic, as identified through international evidence and learning from the International Horizon Scanning Reports. These reports, undertaken between May 2020 - August 2021, are based upon rapid evidence synthesis reviews of international literature. The summary report focuses on global learning and best practices in order to better understand and address the unequal impacts of the pandemic. The information has been categorised according to the five essential conditions required to enable a healthy life as presented within the WHO health equity conditions framework. The report provides evidence on groups most vulnerable to both direct and indirect impacts of the pandemic as well as promising practice to address the resulting inequity. Inequalities and related factors explored within the report include but are not limited to, level of deprivation and education. Taking a global perspective, this report summarises international evidence to support inclusive, sustainable, and equitable solutions, such as protecting economic well-being and taking an intergenerational lens in both response and recovery. To address and mitigate the impact of the pandemic upon vulnerable groups, collating and sharing international evidence and best practice has proven to support equitable long-term socio-economic and environmental recovery.

Key messages

• International learning provides vital insights to support recovery in Wales and beyond.

• Responses to the pandemic should address the needs of the vulnerable to reduce existing health gaps.

Recommendations for Medical and Mental Health Care in Assisted Living Based on an Expert Delphi Consensus Panel: A Consensus Statement

IMPORTANCE

Assisted living (AL) is the largest provider of residential long-term care in the US, and the morbidity of AL residents has been rising. However, AL is not a health care setting, and concern has been growing about residents' medical and mental health needs. No guidance exists to inform this care.

OBJECTIVE

To identify consensus recommendations for medical and mental health care in AL and determine whether they are pragmatic.

EVIDENCE REVIEW

A Delphi consensus statement study was conducted in 2021; as a separate effort, the extent to which the recommendations are reflected in practice was examined in data obtained from 2016 to 2021 (prepandemic). In the separate effort, data were from a 7-state study (Arkansas, Louisiana, New Jersey, New York, Oklahoma, Pennsylvania, Texas). The 19 Delphi panelists constituted nationally recognized experts in medical, nursing, and mental health needs of and care for older adults; dementia care; and AL and long-term care management, advocacy, regulation, and education. One invitee was unavailable and nominated an alternate. The primary outcome was identification of recommended practices based on consensus ratings of importance. Panelists rated 183 items regarding importance to care quality and feasibility.

FINDINGS

Consensus identified 43 recommendations in the areas of staff and staff training, nursing and related services, resident assessment and care planning, policies and practices, and medical and mental health clinicians and care. To determine the pragmatism of the recommendations, their prevalence was examined in the 7-state study and found that most were in practice. The items reflected the tenets of AL, the role of AL in providing dementia care, the need for pragmatism due to the diversity of AL, and workforce needs.

CONCLUSIONS AND RELEVANCE

In this consensus statement, 43 recommendations important to medical and mental health care in AL were delineated that are highly pragmatic as a guide for practice and policy.

Reelin has antidepressant-like effects after repeated or singular peripheral injections

Chronic stress is a significant risk factor for depression onset. The effects of chronic stress can be studied preclinically using a corticosterone (CORT)-administration paradigm that results in a phenotype of depressive-like behavior associated with neurochemical abnormalities in brain regions like the hippocampus. We have recently shown that intrahippocampal infusions of Reelin have a fast effect in normalizing CORT-induced behavioral and neurochemical alterations. Reelin is also expressed in multiple peripheral systems and is found in blood plasma which prompted us to investigate whether peripheral intravenous (i.v.) Reelin injections could also result in antidepressant (ATD)-like actions. Repeated i.v. injections of Reelin were effective in rescuing the CORT-induced increases in forced-swim-test immobility in male and female rats, decreases in Reelin-immunopositive cells in the dentate gyrus subgranular zone, and expression of hippocampal GABA_Aβ 2/3, GluA1, and GluN2B receptors. However, Reelin had only a partial effect on the number and maturation rate of dentate gyrus newborn cells. CORT and Reelin did not affect open field test behavior. After evaluating the effects of multiple Reelin injections, we demonstrated that a single Reelin injection administered at the end of CORT treatment could rescue in 24 h the behavioral (forced-swim-test and object-in-place test), as well as neurochemical effects of CORT. These findings show that i.v. injections of Reelin have fast ATD-like effects associated with the restoration of hippocampal neurochemical deficits. Although additional mechanistic and pharmacokinetic studies are necessary, our data open the possibility to develop Reelin-based therapeutics with putative fast-ATD activity.

Aligning tumor mutational burden (TMB) quantification across diagnostic platforms: phase II of the Friends of Cancer Research TMB Harmonization Project

BACKGROUND

Tumor mutational burden (TMB) measurements aid in identifying patients who are likely to benefit from immunotherapy; however, there is empirical variability across panel assays and factors contributing to this variability have not been comprehensively investigated. Identifying sources of variability can help facilitate comparability across different panel assays, which may aid in broader adoption of panel assays and development of clinical applications.

MATERIALS AND METHODS

Twenty-nine tumor samples and 10 human-derived cell lines were processed and distributed to 16 laboratories; each used their own bioinformatics pipelines to calculate TMB and compare to whole exome results. Additionally, theoretical positive percent agreement (PPA) and negative percent agreement (NPA) of TMB were estimated. The impact of filtering pathogenic and germline variants on TMB estimates was assessed. Calibration curves specific to each panel assay were developed to facilitate translation of panel TMB values to whole exome sequencing (WES) TMB values.

RESULTS

Panel sizes >667 Kb are necessary to maintain adequate PPA and NPA for calling TMB high versus TMB low across the range of cut-offs used in practice. Failure to filter out pathogenic variants when estimating panel TMB resulted in overestimating TMB relative to WES for all assays. Filtering out potential germline variants at >0% population minor allele frequency resulted in the strongest correlation to WES TMB. Application of a calibration approach derived from The Cancer Genome Atlas data, tailored to each panel assay, reduced the spread of panel TMB values around the WES TMB as reflected in lower root mean squared error (RMSE) for 26/29 (90%) of the clinical samples.

CONCLUSIONS

Estimation of TMB varies across different panels, with panel size, gene content, and bioinformatics pipelines contributing to empirical variability. Statistical calibration can achieve more consistent results across panels and allows for comparison of TMB values across various panel assays. To promote reproducibility and comparability across assays, a software tool was developed and made publicly available.

Sustaining suicide prevention programs in American Indian and Alaska Native communities and Tribal health centers

Background:

Research on sustaining community-based interventions is limited. This is particularly true for suicide prevention programs and in American Indian and Alaska Native (AIAN) settings. Aiming to inform research in this area, this paper sought to identify factors and strategies that are key to sustain suicide prevention efforts in AIAN communities.

Methods:

We used a modified Nominal Group Technique with a purposeful sample of N = 35 suicide prevention research experts, program implementors and AIAN community leaders to develop a list of prioritized factors and sustainability strategies. We then compared this list with the Public Health Program Capacity for Sustainability Framework (PHPCSF) to examine the extent the factors identified aligned with the existing literature.

Results:

Major factors identified included cultural fit of intervention approaches, buy in from local communities, importance of leadership and policy making, and demonstrated program success. Strategies to promote these factors included partnership building, continuous growth of leadership, policy development, and ongoing strategic planning and advocacy. All domains of the PHPCF were representative, but additional factors and strategies were identified that emerged as important in AIAN settings.

Conclusions:

Sustaining effective and culturally informed suicide prevention efforts is of paramount importance to prevent suicide and save lives. Future research will focus on generating empirical evidence of these strategies and their effectiveness at promoting program sustainability in AIAN communities.

Intracranial germ cell tumors in Adolescents and Young Adults: European and North American consensus review, current management and future development

The incidence of intracranial germ cell tumors (iGCT) is much lower in European and North American (E&NA) than in Asian population. However, E&NA cooperative groups have simultaneously developed with success treatment strategies with specific attention paid to long-term sequelae. Neurological sequelae may be reduced by establishing a diagnosis with an endoscopic biopsy and/or cerebrospinal fluid (CSF) and/or serum analysis, deferring the need to perform a radical surgery. Depending on markers and/or histological characteristics, patients are treated as either germinoma or non-germinomatous germ cell tumors (NGGCT). Metastatic disease is defined by a positive CSF cytology and/or distant drops in craniospinal MRI. The combination of surgery and/or chemotherapy and radiation therapy is tailored according to grouping and staging. With more than 90% 5-year event-free survival (EFS), localized germinomas can be managed without aggressive surgery, and benefit from chemotherapy followed by whole ventricular irradiation with local boost. Bifocal germinomas are treated as non-metastatic entities. Metastatic germinomas may be cured with craniospinal irradiation. With a 5-year EFS over 70%, NGGCT benefit from chemotherapy followed by delayed surgery in case of residual disease, and some form of radiotherapy. Future strategies will aim at decreasing long-term side effects while preserving high cure rates.

A critique of measures of emotion and empathy in First Peoples' cultural safety in nursing education: A systematic literature review

BACKGROUND

In Australia, undertaking cultural safety education often evokes strong emotional responses by health students. Despite the potential for emotion to drive transformative learning in this space, measures of emotion are uncommon.

AIM

To review existing tools that intend to measure emotional components of learning in relation to cultural safety education.

METHODS

Articles published in English from January 2005 to January 2020; reported studies from Australia, New Zealand, Canada and United States of America; and measured an emotional construct/s after an education intervention offered to university students enrolled in a health programme were included. Studies were assessed for quality according to the Critical Appraisals Skills Programme criteria.

RESULTS

Eight articles were reviewed; five conducted in the United States of America, and three in Australia. Intervention type, measures, methodological rigour and outcomes varied. Studies predominately measured empathy, guilt and/or fear.

CONCLUSIONS

Although students' emotional responses were measured, processes for students to reflect upon these reactions were not incorporated in the classroom. The review has implications for future research and curricula through developments in measuring and acting upon emotion in cultural safety education for nursing students in Australia.

Forecasting the economic consequences of COVID-19 on longstanding illnesses in Wales

Introduction

The unemployment rate following the COVID-19 pandemic in Wales is increasing and there is a positive link between unemployment and longstanding illnesses. This study aimed to project the percentage of adults with longstanding illnesses and chronic health conditions following COVID-19 associated with the economic consequences.

Methods

We retrieved historical data on the unemployment rates and status of longstanding illnesses among adults from the Office for National Statistics (ONS) and National Survey for Wales (NSW), and used time-series models to project the unemployment rates and percentage of adults with longstanding illnesses and chronic health conditions over a three year period (2020/21 - 2022/23).

Results

Without reparative interventions, the unemployment rate is expected to increase sharply from 3.8% in 2019 to about 7% in 2020 following COVID-19 and then gradually increase over the projected period. With increased unemployment, longstanding illness (LSI) would be expected to increase gradually following COVID-19, with an estimated increase of around or exceeding 4% over three years depending on the LSI measure. There would be a higher increment in the percentage of adults with limiting LSI compared with adults with any LSI, suggesting implications for wider health and social care services. With current unemployment predictions, the percentage of adults with chronic health conditions is projected to increase following the COVID-19 pandemic over the projected period, with a higher increment for mental health and endocrine/metabolic conditions

Conclusions

The longstanding illnesses and chronic health conditions are expected to increase in the coming years following COVID-19 pandemic. Therefore, preventative measures for longstanding illnesses and chronic health conditions should be a priority for a sustainable recovery from the COVID-19.

Key messages

Without reparative interventions, the unemployment rate is expected to increase following the COVID-19 pandemic. The projected prevalence of limiting longstanding illness in adults following COVID-19 suggests implications for wider health and social care services.

COVID-19 impact on financial security: evidence from the National Public Engagement Survey in Wales

Background

A nationally representative COVID-19 Public Engagement Survey for Wales, led by the World Health Organization Collaborating Centre on Investment for Health and Well-being at Public Health Wales, has been ongoing from April 2020, helping to inform a sustainable recovery from the COVID-19 pandemic. A data analysis was performed as part of the Welsh Health Equity Status Report initiative focusing on income and job security, which influences living conditions and lifestyle behaviours.

Methods

A Generalized Linear Model was used to calculate the predicted probability of response for variables of interest, e.g. whether an individual reported being in a worse financial situation due to the pandemic, across the life course, socio-economic gradient and sex. Data collected via telephone between 03 April - 25 July 2020 produced a sample ranging between approx. 2,500 - 7,500 participants. The sample was weighted according to deprivation quintile (using the Welsh Index of Multiple Deprivation), age group and sex.

Results

A significantly higher proportion of survey respondents (18 - 24 years of age) reported being worried about losing their job or not being able to find one, than any other age group. A significantly higher proportion of survey respondents in the most deprived population fifth (33.7%) reported being in a worse financial situation as a result of the restrictions, compared to the least deprived fifth (21.7%).

Conclusions

COVID-19 has had a major impact on people's lives and livelihoods in Wales, hitting the most deprived and vulnerable the most. It has increased job insecurity, especially among younger/working age people. The government has taken unprecedented financial and other measures to address inequities; nevertheless, most are temporary and not specifically targeted to support specific (vulnerable) groups. Measures to promote sustainable economic recovery, job security and safeguarding due to the COVID-19 pandemic need continuity and consistency

Key messages

COVID-19 has had a significant impact on income and job security in Wales, disproportionately affecting the most deprived. To mitigate COVID-19 harms, a continuous and consistent focus on equity is essential to promote sustainable economic recovery.

COVID-19 International Horizon Scanning – informing a response and recovery in Wales and beyond

Issue

The rapidly evolving nature and uncertainties of the COVID-19 pandemic have led to unprecedented challenges for health systems, as well as to wellbeing, social and economic impacts for individuals and communities across the globe. Effective, dynamic, innovative and evidence-based solutions are needed to address these challenges.

Description of Problem

The World Health Organization (WHO) Collaborating Centre on Investment for Health and Well-being, Public Health Wales, has initiated and continues to perform International Horizon Scanning work to inform the evolving COVID-19 public health response and recovery plans in Wales by learning from best practices from other countries. The learning and intelligence is systematically synthesized in rapid regular reports published every week/two weeks. The focus and scope vary, depending on the COVID-19 situation and public health and policy needs.

Results

The work stream has provided Welsh Government, the National Health Service (NHS), Public Health Wales and other key stakeholders with continuous and timely learning from the experience of other countries along with emerging evidence and guidance, provided by key international organisations. This includes international evidence, epidemiological data, experience, measures and recovery approaches, to understand and explore solutions. Reports have given a consistent overview of approaches across countries such as a comparative analysis of the vaccine roll-out or a systematic overview of the R-value and measures implemented accordingly.

Lessons

To understand, mitigate and address the impacts of the pandemic in Wales and beyond, a timely, dynamic and evidence-informed actionable intelligence has proven to be essential to inform and support decision-making on government and health system level to address the pandemic and mitigate harms from COVID-19.

Key messages

International learning has and continues to inform the evolving COVID-19 public health response in Wales.

Public Health Wales is contributing to an evidence-informed inclusive recovery from the pandemic in Wales and beyond.

Is all conflict the same? The role of perceived intensity in understanding its effects

While interpersonal conflict at work continues to draw attention, researchers have rarely considered the role that conflict intensity plays in amplifying individuals' affective reactions to it. Hence, this study examines conflict intensity as a moderator of the relationship between interpersonal conflict and perceived stress, physical symptoms, and job satisfaction, through negative affect. A total of 306 employees from various industries participated in this cross-sectional study. Supporting and expanding an emotion-centered model of conflict, results indicated that the indirect effects of conflict on the study's outcomes were higher when participants perceived the conflict to be of medium and high-level intensity.

Abstract 1006: Combination therapy with MEK inhibitors and a novel anti-neoplastic drug, imipridone ONC212, demonstrates synergy in pancreatic ductal adenocarcinoma cell lines

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with limited therapeutic options. Although KRAS is mutated or amplified in nearly 95% of PDAC, no effective KRAS directed therapy has entered clinical practice. There is emerging data suggesting that inhibition of downstream targets of KRAS, such as MEK or ERK, increases autophagic flux and dependence in KRAS-mutated tumors. Autophagy, a catabolic process used by many tumors to maintain viability, can be targeted with various agents such has hydroxychloroquine and chloroquine, and recent preclinical data has shown that the combination of these agents with inhibitors of MEK/ERK can synergistically induce cell death. Using viability assays, we established sensitivity of multiple KRAS-mutated and KRAS wild-type pancreatic cancer cell lines, BxPC3, PANC1, HPAF-II, AsPC-1 to ONC212, trametinib, chloroquine and combinations of these agents. Results were analyzed after 72 hours of incubation using Compusyn and Combenefit. We also performed Western Blotting on cell lysates after treatment for 48 hours with these agents. We found that trametinib exhibited strong synergy with both chloroquine and ONC212 in all cell lines. The synergistic potential appeared to be most profound in those cell lines treated with ONC212 and trametinib. We used MRC5, a normal lung fibroblast cell line, as a control and found that these combinations did not significantly induce cell death. Using Western Blotting, we assessed markers of autophagy, including Beclin-1 and LC3B, as well as key second messenger pathway activation/suppression with p-AKT/AKT and p-ERK/ERK. At increasing doses, trametinib increased conversion of LC3-I to LC3-II, more notably in KRAS mutant cell lines, suggesting increased autophagic flux. ONC212, however, reduced conversion of LC3-I to LC3-II and increased degradation of Beclin-1 suggesting inhibition of autophagy. The combination, did not appear to have as striking of an effect on this pathway. In addition, p-ERK, as expected, was downregulated with MEK inhibition. ONC212 also appeared to reduce p-ERK levels and, interestingly, increased p-AKT. This suggests possible PI3K pathway upregulation, however, this could be influenced by timing and dose of treatments. Western blot analysis also revealed increased cPARP/PARP with combination therapy across cell lines. In conclusion, the combination of trametinib and ONC212 produces a synergistic cytotoxic effect on tumor cells at doses that are non-toxic to normal cells. In KRAS-mutated pancreatic cancer cell lines, we hypothesize that this may, in part, be due to autophagy suppression by ON212. Similar synergistic effects were noted in a KRAS wild-type pancreatic cancer cell lines, suggesting an autophagy-independent mechanism. Thus, this combination may represent a potential therapeutic modality for PDAC.

Citation Format: Alexander G. Raufi, Casssandra Parker, Lanlan Zhou, Varun V. Prabhu, Josh Allen, Wafik S. El-Deiry. Combination therapy with MEK inhibitors and a novel anti-neoplastic drug, imipridone ONC212, demonstrates synergy in pancreatic ductal adenocarcinoma cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1006.

Abstract 1044: ONC201 as a novel anti-cancer therapeutic via modulation of inhibitors of apoptosis and up-regulation of DR5 in gastric adenocarcinoma

Gastric adenocarcinoma is commonly asymptomatic early in its course, leading to late-stage diagnosis at a time when patients are inoperable. Currently available chemotherapy options are non-targeted and highly toxic, leading to a poor 5-year survival of only 31.5%. ONC201 is a small molecule imipridone anti-cancer therapy discovered by our lab that induces cell death in a variety of malignant tumors via a multitude of mechanisms including activation of the integrated stress response (ISR) leading to up-regulation of TNF-related apoptosis-inducing ligand (TRAIL), which induces apoptosis after binding to the death receptor 5 (DR5). We investigated the ability of ONC201 to induce cell death in gastric adenocarcinoma cells when used in combination with recombinant human TRAIL (rhTRAIL), and its affect on DR5 cell surface expression and expression of inhibitors of apoptosis (IAP) in order to further establish mechanism of action. AGS (caspase 8, KRAS, PIK3CA mutant, HER2 amplified), SNU-1 (KRAS and MLH1 mutant, microsatellite instable), SNU-5 (p53 mutant) and SNU-16 (p53 mutant) gastric adenocarcinoma cell lines were treated with ONC201 and rhTRAIL and viability assays were performed to determine cell line sensitivities. All lines were then treated with combination therapy based on sensitivities and viability assays were performed in order to determine combination indices. Cell death was verified with sub-G1 analysis via flow cytometry and protein expression was established via western blotting. All cell lines exhibited strong synergy in response to dual therapy with ONC201 and rhTRAIL, with combination indices &lt;0.6 at doses that did not induce cell death in normal fibroblast cells. Synergy was confirmed via flow cytometry analysis with increased cells in the sub-G1 phase of the cell cycle with dual therapy in excess of what would be expected from an additive effect. On western blot analysis, apoptosis was confirmed with increased cleavage of PARP, caspase 8 and caspase 3 after dual treatment with ONC201 and rhTRAIL. Flow cytometry revealed increased cell surface expression of DR5 with ONC201 therapy, and western blot analysis showed that ONC201 lead to up-regulation of ATF-4 and CHOP, indicating activation of the ISR, and down-regulation of anti-apoptotic CIAP-2 and XIAP in all cell lines except AGS, as well as FLIP in all cell lines except SNU-16. These in vitro results suggest that ONC201 in combination with rhTRAIL may be an effective and non-toxic option for the treatment of gastric adenocarcinoma by inducing apoptosis via activation of the ISR, increased cell surface expression of DR5 and down-regulation of inhibitors of apoptosis. We are currently applying this regimen to an organoid model, as well as a murine sub-cutaneous xenograft model using AGS and SNU-1 cells.

Citation Format: Cassandra Susan Parker, Lanlan Zhou, Varun Prabhu, Josh Allen, Wafik El-Deiry. ONC201 as a novel anti-cancer therapeutic via modulation of inhibitors of apoptosis and up-regulation of DR5 in gastric adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1044.

182 Treating Distal Femur Fractures Without Fluoroscopy: Comparison of Implants Used in a Rural Hospital in Tanzania

Introduction

SIGN is a charity providing implants for hospitals with limited resources. There are two nails that can be inserted without fluoroscopy - the standard SIGN nail and the Fin nail. We aimed to evaluate the effectiveness of these implants in treating distal femur fractures.

Method

Retrospective analysis of SIGN database at Nkoaranga Hospital, Tanzania between July 2017 and January 2019. 28 patients (20 male, 8 female) with distal femur fractures had a standard nail (n = 14) or a Fin nail (n = 14). Inclusion criteria: distal femur fractures treated with intramedullary nail. Exclusion criteria: age&lt;16, open injury, antegrade approach, no follow-up at 4 weeks.

Results

Mean age was 41.4 (18-81). Average time from injury to surgery was 29 days. Average first follow-up was 14 weeks (4-73). Painless weight-bearing was achieved in 93% (13/14) of standard nails and 100% (14/14) of Fin nails. Knee flexion &gt;30° was 64% (9/14) in standard nails and 50% (7/14) in Fin nails. Screw loosening was seen in 7% (1/14) in standard nails and no patients with Fin nails. There were no instances of implant breakage, clinical deformity, or infection.

Conclusions

Patients had variable follow-up and presented late causing delayed treatment. Both nails can achieve excellent results. A larger sample size is required.

O61: TEXTBOOK SURGICAL OUTCOMES IN OESOPHAGO-GASTRIC CANCER: THE INFLUENCE OF NATIONAL KEY PERFORMANCE INDICATORS

Introduction

High quality surgery remains the cornerstone of treating oesophago-gastric malignancy. Recent work from the Dutch Upper-gastrointestinal Cancer Audit (DUCA) have defined ten surgical and perioperative ‘textbook’ parameters that correlate with improved overall survival. The aim of this project was to examine the proportion of patients attaining ‘textbook’ outcomes for oesophagectomy and gastrectomy in our unit before and after the introduction of national key performance indicators (KPIs).

Method

A retrospective review of all oesophagectomies and gastrectomies from January 2010 until June 2019 was performed. Clinical, pathological, perioperative, morbidity and mortality outcomes were recorded. 10 ‘textbook’ parameters were studied pre- and post-KPI introduction.

Result

269 and 284 patients underwent oesophagectomy and gastrectomy respectively, 167 pre-KPI and 386 post-KPI. There were no significant differences in age (67.6 vs 66.4 years, p=0.6), gender (71% male, 29% female vs 68% male, 22% female, p=0.48), ASA grade (p=0.6) or tumour stage (p=0.37) pre- and post-KPI. In the pre-KPI era, 28/167 (17%) patients achieved all ten textbook parameters, compared with 157/386, (41%, p=0.001) post-KPI. This compares favourably to DUCA ‘textbook’ data. There was an improvement in adequate lymphadenectomy (56% vs 83%, p=0.002), a reduction in margin positivity (21% vs 7%, p= 0.001) and peri-operative mortality (6% vs 2%, p=0.03) post-KPI.

Conclusion

There has been a significant improvement in perioperative outcomes in esophagectomy following the introduction of national KPIs in our unit. The number of patients achieving ‘textbook’ outcomes is comparable with international standards. The identification of textbook parameters allows further focus for future quality improvement initiatives.

Take-home message

National KPIs improve peri-operative outcomes in oesophago-gastric cancer.

Patient oriented research in mental health: matching laboratory to life and beyond in Canada

As patient-oriented research gains popularity in clinical research, the lack of patient input in foundational science grows more evident. Research has shown great utility in active partnerships between patient partners and scientists, yet many researchers are still hesitant about listening to the voices of those with lived experience guide and shape their experiments. Mental health has been a leading area for patient movements such as survivor-led research, however the stigma experienced by these patients creates difficulties not present in other health disciplines. The emergence of COVID-19 has also created unique circumstances that need to be addressed. Through this lens, we have taken experiences from our patient partners, students, and primary investigator to create recommendations for the better facilitation of patient-oriented research in foundational science in Canada. With these guidelines, from initial recruitment and leading to sustaining meaningful partnerships, we hope to encourage other researchers that patient-oriented research is necessary for the future of mental health research and foundational science.

Anger bias in the evaluation of crowds

People are good at categorizing the emotions of individuals and crowds of faces. People also make mistakes when classifying emotion. When they do so with judgments of individuals, these errors tend to be negatively biased, potentially serving a protective function. For example, a face with a subtle expression is more likely to be categorized as angry than happy. Yet surprisingly little is known about the errors people make when evaluating multiple faces. We found that perceivers were biased to classify faces as angry, especially when evaluating crowds. This amplified bias depended on uncertainty, occurring when categorization was difficult, and it reached peak intensity for crowds with four members. Drift diffusion modeling revealed the mechanisms behind this bias, including an early response component and more efficient processing of anger from crowds with subtle expressions. Our findings introduce bias as an important new dimension for understanding how perceivers make judgments about crowds. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Severe life stress, mitochondrial dysfunction, and depressive behavior: A pathophysiological and therapeutic perspective

Mitochondria are responsible for providing our cells with energy, as well as regulating oxidative stress and apoptosis, and considerable evidence demonstrates that mitochondria-related alterations are prevalent during chronic stress and depression. Here, we discuss how chronic stress may induce depressive behavior by potentiating mitochondrial allostatic load, which ultimately decreases energy production, elevates the generation of harmful reactive oxygen species, damages mitochondrial DNA and increases membrane permeability and pro-apoptotic factor release. We also discuss how mitochondrial insults can exacerbate the immune response, contributing to depressive symptomology. Furthermore, we illustrate how depression symptoms are associated with specific mitochondrial defects, and how targeting of these defects with pharmacological agents may be a promising avenue for the development of novel, more efficacious antidepressants. In summary, this review supports the notion that severe psychosocial stress induces mitochondrial dysfunction, thereby increasing the vulnerability to developing depressive symptoms.

Diel cycles of carbon, nutrient and metal in humic lakes of permafrost peatlands

Despite the importance of surface waters of permafrost landscapes in carbon (C) emission and dissolved C and metal storage and export, the majority of available observations in high latitude aquatic systems deal with punctual or seasonal sampling without accounting for diurnal variations in temperature and primary productivity-respiration cycles. Towards providing comprehensive understanding of diel variations in CO₂ emission, organic C and element concentrations in lakes of frozen peatlands, we monitored, each 2 h over 2 days, the water temperature, pH, CO₂ fluxes, CO₂, CH₄, dissolved organic and inorganic carbon (DOC and DIC, respectively), nutrients, carboxylic acids, bacterial number, and major and trace elements in two acidic (pH = 3.6 and 4.0) and humic (DOC = 15 and 35 mg L^-1) thermokarst lakes of discontinuous permafrost zone in Western Siberia. We discovered a factor of 2 to 3 higher CO₂ concentrations and fluxes during the night compared to daytime in the high-DOC lake. The emission fluxes in the low-DOC lake increased from zero to negative values during the day to highly positive values during the end of night and early morning. The methane concentration varied within a factor of 5 without any link to the diurnal cycle. The bulk of dissolved (< 0.45 μm) hydrochemical parameters remained highly stable with ±10% variation in concentration over 2 days of observation (DOC, DIC, SUVA_254nm, carboxylates (formate, oxalate, puryvate and glutarate), Mn, Fe, Al, other trace elements). Concentrations of Si, P, K, Cu varied within ±20% whereas those of Zn and Ni ranged by a factor of 2 to 4 without any link to diurnal pattern. Overall, the impact of diel cycle on CH₄, DOC, nutrient and metal concentration was below 10%. However, neglecting night-time period may underestimate net CO₂ emission by ca. 30 to 50% in small organic-rich thaw ponds and switch the CO₂ exchange from uptake/zero to net emission in larger thermokarst lakes. Given the dominance of large lakes in permafrost regions, the global underestimation of the emission flux may be quite high. As such, monitoring CO₂ concentrations and fluxes in thermokarst lakes during months of extended night time (August to October) is mandatory for assessing the net emissions from lentic waters of frozen peatlands.