Intramuscular diacylglycerol accumulates with acute hyperinsulinemia in insulin-resistant phenotypes.

Elevated skeletal muscle diacylglycerols (DAGs) and ceramides can impair insulin signaling, and acylcarnitines (acylCNs) reflect impaired mitochondrial fatty acid oxidation, thus, the intramuscular lipid profile is indicative of insulin resistance. Acute (i.e., postprandial) hyperinsulinemia has been shown to elevate lipid concentrations in healthy muscle and is an independent risk factor for type 2 diabetes (T2D). However, it is unclear how the relationship between acute hyperinsulinemia and the muscle lipidome interacts across metabolic phenotypes, thus contributing to or exacerbating insulin resistance. We therefore investigated the impact of acute hyperinsulinemia on the skeletal muscle lipid profile to help characterize the physiological basis in which hyperinsulinemia elevates T2D risk. In a cross-sectional comparison, endurance athletes (n = 12), sedentary lean adults (n = 12), and individuals with obesity (n = 13) and T2D (n = 7) underwent a hyperinsulinemic-euglycemic clamp with muscle biopsies. Although there were no significant differences in total 1,2-DAG fluctuations, there was a 2% decrease in athletes versus a 53% increase in T2D during acute hyperinsulinemia (P = 0.087). Moreover, C18 1,2-DAG species increased during the clamp with T2D only, which negatively correlated with insulin sensitivity (P < 0.050). Basal muscle C18:0 total ceramides were elevated with T2D (P = 0.029), but not altered by clamp. Acylcarnitines were universally lowered during hyperinsulinemia, with more robust reductions of 80% in athletes compared with only 46% with T2D (albeit not statistically significant, main effect of group, P = 0.624). Similar fluctuations with acute hyperinsulinemia increasing 1,2 DAGs in insulin-resistant phenotypes and universally lowering acylcarnitines were observed in male mice. In conclusion, acute hyperinsulinemia elevates muscle 1,2-DAG levels with insulin-resistant phenotypes. This suggests a possible dysregulation of intramuscular lipid metabolism in the fed state in individuals with low insulin sensitivity, which may exacerbate insulin resistance.NEW & NOTEWORTHY Postprandial hyperinsulinemia is a risk factor for type 2 diabetes and may increase muscle lipids. However, it is unclear how the relationship between acute hyperinsulinemia and the muscle lipidome interacts across metabolic phenotypes, thus contributing to insulin resistance. We observed that acute hyperinsulinemia elevates muscle 1,2-DAGs in insulin-resistant phenotypes, whereas ceramides were unaltered. Insulin-mediated acylcarnitine reductions are also hindered with high-fat feeding. The postprandial period may exacerbate insulin resistance in metabolically unhealthy phenotypes.

Loss of α-actinin-3 during human evolution provides superior cold resilience and muscle heat generation.

The protein α-actinin-3 expressed in fast-twitch skeletal muscle fiber is absent in 1.5 billion people worldwide due to homozygosity for a nonsense polymorphism in ACTN3 (R577X). The prevalence of the 577X allele increased as modern humans moved to colder climates, suggesting a link between α-actinin-3 deficiency and improved cold tolerance. Here, we show that humans lacking α-actinin-3 (XX) are superior in maintaining core body temperature during cold-water immersion due to changes in skeletal muscle thermogenesis. Muscles of XX individuals displayed a shift toward more slow-twitch isoforms of myosin heavy chain (MyHC) and sarcoplasmic reticulum (SR) proteins, accompanied by altered neuronal muscle activation resulting in increased tone rather than overt shivering. Experiments on Actn3 knockout mice showed no alterations in brown adipose tissue (BAT) properties that could explain the improved cold tolerance in XX individuals. Thus, this study provides a mechanism for the positive selection of the ACTN3 X-allele in cold climates and supports a key thermogenic role of skeletal muscle during cold exposure in humans.

Quasiparticle Poisoning of Superconducting Qubits from Resonant Absorption of Pair-Breaking Photons.

The ideal superconductor provides a pristine environment for the delicate states of a quantum computer: because there is an energy gap to excitations, there are no spurious modes with which the qubits can interact, causing irreversible decay of the quantum state. As a practical matter, however, there exists a high density of excitations out of the superconducting ground state even at ultralow temperature; these are known as quasiparticles. Observed quasiparticle densities are of order 1 µm^{-3}, tens of orders of magnitude greater than the equilibrium density expected from theory. Nonequilibrium quasiparticles extract energy from the qubit mode and can induce dephasing. Here we show that a dominant mechanism for quasiparticle poisoning is direct absorption of high-energy photons at the qubit junction. We use a Josephson junction-based photon source to controllably dose qubit circuits with millimeter-wave radiation, and we use an interferometric quantum gate sequence to reconstruct the charge parity of the qubit. We find that the structure of the qubit itself acts as a resonant antenna for millimeter-wave radiation, providing an efficient path for photons to generate quasiparticles. A deep understanding of this physics will pave the way to realization of next-generation superconducting qubits that are robust against quasiparticle poisoning.

A single bout of vigorous intensity exercise enhances the efficacy of rituximab against human chronic lymphocytic leukaemia B-cells ex vivo.

Chronic lymphocytic leukaemia (CLL) is characterised by the clonal proliferation and accumulation of mature B-cells and is often treated with rituximab, an anti-CD20 monoclonal antibody immunotherapy. Rituximab often fails to induce stringent disease eradication, due in part to failure of antibody-dependent cellular cytotoxicity (ADCC) which relies on natural killer (NK)-cells binding to rituximab-bound CD20 on B-cells. CLL cells are diffusely spread across lymphoid and other bodily tissues, and ADCC resistance in survival niches may be due to several factors including low NK-cell frequency and a suppressive stromal environment that promotes CLL cell survival. It is well established that exercise bouts induce a transient relocation of NK-cells and B-cells into peripheral blood, which could be harnessed to enhance the efficacy of rituximab in CLL by relocating both target and effector cells together with rituximab in blood. In this pilot study, n = 20 patients with treatment-naïve CLL completed a bout of cycling 15 % above anaerobic threshold for âˆ¼ 30-minutes, with blood samples collected pre-, immediately post-, and 1-hour post-exercise. Flow cytometry revealed that exercise evoked a 254 % increase in effector (CD3-CD56+CD16+) NK-cells in blood, and a 67 % increase in CD5+CD19+CD20+ CLL cells in blood (all p < 0.005). NK-cells were isolated from blood samples pre-, and immediately post-exercise and incubated with primary isolated CLL cells with or without the presence of rituximab to determine specific lysis using a calcein-release assay. Rituximab-mediated cell lysis increased by 129 % following exercise (p < 0.001). Direct NK-cell lysis of CLL cells - independent of rituximab - was unchanged following exercise (p = 0.25). We conclude that exercise improved the efficacy of rituximab-mediated ADCC against autologous CLL cells ex vivo and propose that exercise should be explored as a means of enhancing clinical responses in patients receiving anti-CD20 immunotherapy.

Myths and Methodologies: Standardisation in human physiology research-should we control the controllables?

The premise of research in human physiology is to explore a multifaceted system whilst identifying one or a few outcomes of interest. Therefore, the control of potentially confounding variables requires careful thought regarding the extent of control and complexity of standardisation. One common factor to control prior to testing is diet, as food and fluid provision may deviate from participants' habitual diets, yet a self-report and replication method can be flawed by under-reporting. Researchers may also need to consider standardisation of physical activity, whether it be through familiarisation trials, wash-out periods, or guidance on levels of physical activity to be achieved before trials. In terms of pharmacological agents, the ethical implications of standardisation require researchers to carefully consider how medications, caffeine consumption and oral contraceptive prescriptions may affect the study. For research in females, it should be considered whether standardisation between- or within-participants in regards to menstrual cycle phase is most relevant. The timing of measurements relative to various other daily events is relevant to all physiological research and so it can be important to standardise when measurements are made. This review summarises the areas of standardisation which we hope will be considered useful to anyone involved in human physiology research, including when and how one can apply standardisation to various contexts.

Extracorporeal Membrane Oxygenation-Associated Compartment Syndrome: Review of a National Database.

INTRODUCTION: Extracorporeal membrane oxygenation (ECMO)-associated compartment syndrome (CS) is a rare complication seen in critically ill patients. The epidemiology and management of ECMO-associated CS in the upper extremity (UE) and lower extremity (LE) are poorly defined in the literature. We sought to determine the epidemiology and characterize treatment and outcomes of UE-CS compared to LE-CS in the setting of ECMO therapy. METHODS: Adult patients undergoing ECMO therapy were identified in the Nationwide Readmission Database (2015-2019) and followed up for 6 months. Patients were stratified based on UE-CS versus LE-CS. Primary outcomes were fasciotomy and amputation. All-cause mortality and length of stay were also collected. Risk-adjusted modeling was performed to determine patient- and hospital-level factors associated with differences in the management UE-CS versus LE-CS while controlling for confounders. RESULTS: A total of 24,047 cases of ECMO during hospitalization were identified of which 598 were complicated by CS. Of this population, 507 cases were in the LE (84.8%), while 91 (15.5%) were in the UE. After multivariate analysis, UE-CS patients were less likely to undergo fasciotomy (50.5 vs. 70.9; P = 0.013) and were less likely to undergo amputation of the extremity (3.3 vs. 23.7; P = 0.001) although there was no difference in mortality (58.4 vs. 65.4; P = 0.330). CONCLUSIONS: ECMO patients with CS experience high mortality and morbidity. UE-CS has lower rates of fasciotomy and amputations, compared to LE-CS, with similar mortality. Further studies are needed to elucidate the reasons for these differences.

More Than Under-Eye Bags: Treatment of Formidable Festoons.

A 64-year-old male with no medical care over the last decade was transferred from his local emergency room to a level 1 trauma center following an unwitnessed fall. Upon ophthalmic evaluation, he was noted to have significant lethargy and bilateral large festoons with secondary ectropion. Laboratory workup revealed severe hypothyroidism, consistent with myxedema coma, and his lethargy improved with medical treatment. The festoons were surgically removed to address the ectropion, and the patient was satisfied with the results following a single procedure. This case report features the largest reported festoons to date in the literature and emphasizes the importance of balancing cosmesis with function during surgical excision and correction of ectropion.

Myths and Methodologies: Standardisation in Human Physiology Research-Should We Control the Controllables?

The premise of research in human physiology is to explore a multifaceted system whilst identifying one or a few outcomes of interest. Therefore, the control of potentially confounding variables requires careful thought regarding the extent of control and complexity of standardisation. One common factor to control prior to testing is diet, as food and fluid provision may deviate from participants' habitual diets, yet a self-report and replication method can be flawed by under-reporting. Researchers may also need to consider standardisation of physical activity, whether it be through familiarisation trials, wash-out periods, or guidance on levels of physical activity to be achieved before trials. In terms of pharmacological agents, the ethical implications of standardisation require researchers to carefully consider how medications, caffeine consumption and oral contraceptive prescriptions may affect the study. For research in females, it should be considered whether standardisation between- or within-participants in regards to menstrual cycle phase is most relevant. The timing of measurements relative to various other daily events is relevant to all physiological research and so it can be important to standardise when measurements are made. This review summarises the areas of standardisation which we hope will be considered useful to anyone involved in human physiology research, including when and how one can apply standardisation to various contexts.

Proximal lateral insertion portal of an intra-articular arthroscopic stifle lever: A cadaveric study.

OBJECTIVE: To (1) Describe the proximal lateral insertion portal for the placement of an intra-articular distraction lever. (2) Assess for associated damage with the insertion of the lever and (3) evaluate the impact of duration of lever use on articular cartilage damage. STUDY DESIGN: Ex vivo canine cadaveric experimental study. ANIMALS: Paired canine stifles from seven cadavers (14 stifles from dogs weighing >20 kg). METHODS: A separate 0.5 cm proximal lateral portal was established adjacent to the lateral scope portal. A standard Ventura stifle thrust lever (VSTL) was inserted without removing the arthroscope. In Group A, the VSTL was placed in distraction for 5 min while in Group B the VSTL was placed for 10 min. The stifle joints were disarticulated and evaluated for associated damage to the long digital extensor tendon and iatrogenic articular cartilage injury (IACI) via India ink assay. RESULTS: No damage to the long digital extensor tendon was noted in any of the specimens during dissection. Superficial IACI was present in all specimens. There were no differences between groups when assessing for overall IACI. CONCLUSION: A proximal lateral portal and insertion of a standard VSTL can be performed without removing the arthroscope. CLINICAL SIGNIFICANCE: The use of a proximal lateral lever portal without repositioning the arthroscope was repeatable without damaging the long digital extensor tendon. A duration of up to 10 min in which the thrust lever was engaged did not result in increased visual cartilage damage.

Increased Patient Age as a Risk Factor Following Free Flap Reconstruction after Breast Cancer: A Single Institutional Review of 2,598 Cases.

BACKGROUND: Autologous breast reconstruction (ABR) after mastectomy is increasing due to benefits over implant-based reconstruction. However, free flap reconstruction is not universally offered to patients of advanced age due to perceived increased perioperative risk. METHODS: Patients undergoing free flap breast reconstruction at our institution from 2005 to 2018 were included. Risk-adjusted logistic regression models were fit while controlling for demographic and comorbid characteristics to determine the association of age with the probability of venous thromboembolism (VTE), delayed healing, skin necrosis, surgical site infection (SSI), seroma, hematoma, hernia, and flap loss. Linear predictions from risk-adjusted logistic regression models were used to create spline curves and determine the risk of outcomes associated with age. RESULTS: A cohort of 2,598 patients underwent free flap breast reconstruction in the period examined. The median age was 51 with approximately 9% of patients being 65 or older. Increased age was associated with a greater risk of delayed healing, skin necrosis, and hematoma after surgery. There was no increased risk of medical complications such as VTE or complications such as flap loss, seroma, or SSI. CONCLUSION: A set age cutoff for patients undergoing free flap breast reconstruction does not appear warranted. There is no difference in major surgical complications such as flap loss with increasing age. However, older age does predispose patients to specific wound complications such as hematoma, skin necrosis, and delayed wound healing, which should guide preoperative counseling. Further, medical complications do not increase with advanced age. Overall, however, the safety of ABR in older patients appears uncompromised.

THE GODINA PRINCIPLE IN THE 21ST CENTURY: FREE FLAP TIMING AFTER ISOLATED LOWER EXTREMITY TRAUMA IN A RETROSPECTIVE NATIONAL COHORT.

BACKGROUND: The timing of free flap reconstruction after lower extremity trauma has been a controversial debate since Marko Godina's original 72 hour recommendation. Recent advances in microsurgery warrant an evaluation of the optimal time to reconstruction. METHODS: The Nationwide Readmission Database (2014-2019) was used to identify patients undergoing free flap reconstruction after lower extremity trauma. Risk-adjusted statistical methods were used to identify optimal time where risk of infectious and microsurgical complications increase and to quantify the risk associated with time delays. RESULTS: One-thousand and thirty patients undergoing reconstruction were identified. The mean time to flap coverage was 24.3 days. Thirty-three percent were performed within 72 hours, 24% from 72 hours-10 days, 18% from 10-30 days, and 24% after 30 days. Flaps performed after 10 days were associated with increased risk of surgical site infection, osteomyelitis, and other wound complications, compared to those performed within 72 hours. There was no increased risk in the period of 72 hours to 10 days. Revision amputation and microsurgical complications were not increased after 10 days. The predicted optimal cutoff was 9.5 days for microsurgical complications and 14.5 days for infectious complications. CONCLUSIONS: Advances in microsurgery may be responsible for extending the time in which definitive soft tissue coverage is required for wounds resulting from lower extremity trauma. Although it appears the original 72-hour time window can be safely extended, efforts should be made to refer patients to specialty limb salvage centers in a timely fashion.

Review of 451 Patients Presenting With Orbital Wall Fractures: A Retrospective Analysis.

A retrospective review of the electronic medical records of patients presenting to the University Medical Center in Lubbock, Texas with orbital wall fractures. Clinical data such as associated ocular injuries and different management approaches are analyzed and discussed to help clarify the specific indications for, and timing of, a formal ophthalmologic examination. All patients who presented to the emergency department for an orbital fracture after suffering various types of traumas between 2008 and 2017 were included. The study reviewed 451 patients with orbital wall fractures with a wide variety of presentations as well as demographics. There were 411 cases of adults presenting with an average age of 34 years and 40 pediatric presentations with an average age of 14 years. The average age of the combined study population was 30 years. Only 16.9% of patients required surgical correction for their orbital fractures and assault accounted for nearly 50% of all the orbital fractures reviewed in this study. In this large retrospective review, no notable relationship was found between orbital wall fractured and ocular injury. Alarm symptoms for more visual threatening injuries such as retinal tears, detachments, open globe injury, and extraocular muscle entrapment are all reasonable indications to consult ophthalmology emergently. Most orbital fractures are not vision threatening, do not usually require surgical correction, and typically occur in the setting of assault.

Obesity as a Risk Factor in Cosmetic Abdominal Body Contouring: A Systematic Review and Meta-Analysis.

BACKGROUND: The incidence of obesity is on the rise around the globe. Outside of the massive weight loss (MWL) patient population, knowledge of risk factors associated with abdominal body contouring (BC) is limited. This systematic review and meta-analysis assesses the impact of obesity has on cosmetic abdominal BC outcomes. METHODS: A systematic review conducted in accordance with PRISMA 2020 was done. PubMed, Embase, Scopus, and COCHRANE databases were reviewed under search syntax "obesity," "abdominoplasty," "panniculectomy," and "body contouring" for articles. Cosmetic was defined as abdominoplasty or panniculectomy outside the context of MWL. Obesity was defined as BMI ≥ 30 kg/m2. Studies reporting postoperative outcomes with less than 50% of their population involving MWL patients were included. Postoperative outcomes were assessed by pooled analysis and meta-analysis. RESULTS: Of 3088 initial studies, 16 met inclusion criteria, and nine were used for pooled and meta-analysis. Meta-analysis demonstrated that obesity was associated with more seromas (OR 1.45, 1.06-1.98, p = 0.02), hematomas (OR 2.21, 1.07-4.57, p = 0.03), and total surgical site occurrences (OR 1.99, 1.30-3.04, p = 0.0016). There was no significant difference in odds of any other complications. Analysis by obesity class showed no significant increase in odds in seromas or wound dehiscence. CONCLUSIONS: This review demonstrates obesity increased odds of postoperative complications following cosmetic abdominal BC. However, risk of complications does not continue to increase with higher obesity class. A BMI ≥ 30 kg/m2 should not be a strict contraindication to cosmetic abdominal BC. Instead, plastic surgeons should evaluate patients on a case-by-case basis. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The effects of exercise on complement system proteins in humans: a systematic scoping review.

BACKGROUND: The complement system is comprised of the classical, lectin and alternative pathways that result in the formation of: pro-inflammatory anaphylatoxins; opsonins that label cells for phagocytic removal; and, a membrane attack complex that directly lyses target cells. Complement-dependent cytotoxicity (CDC) - cell lysis triggered by complement protein C1q binding to the Fc region of antibodies bound to target cells - is another effector function of complement and a key mechanism-of-action of several monoclonal antibody therapies. At present, it is not well established how exercise affects complement system proteins in humans. METHODS: A systematic search was conducted to identify studies that included original data and investigated the association between soluble complement proteins in the blood of healthy humans, and: 1) an acute bout of exercise; 2) exercise training interventions; or, 3) measurements of habitual physical activity and fitness. RESULTS: 77 studies were eligible for inclusion in this review, which included a total of 10,236 participants, and 40 complement proteins and constituent fragments. Higher levels of exercise training and cardiorespiratory fitness were commonly associated with reduced C3 in blood. Additionally, muscle strength was negatively associated with C1q. Elevated C3a-des-Arg, C4a-des-Arg and C5a, lower C1-inhibitor, and unchanged C3 and C4 were reported immediately post-laboratory based exercise, compared to baseline. Whereas, ultra-endurance running and resistance training increased markers of the alternative (factor B and H), classical (C1s), and leptin (mannose binding lectin) pathways, as well as C3 and C6 family proteins, up to 72-h following exercise. Heterogeneity among studies may be due to discrepancies in blood sampling/handling procedures, analytical techniques, exercise interventions/measurements and fitness of included populations. CONCLUSIONS: Increased anaphylatoxins were observed immediately following an acute bout of exercise in a laboratory setting, whereas field-based exercise interventions of a longer duration (e.g. ultra-endurance running) or designed to elicit muscle damage (e.g. resistance training) increased complement proteins for up to 72-h. C3 in blood was mostly reduced by exercise training and associated with increased cardiorespiratory fitness, whereas C1q appeared to be negatively associated to muscle strength. Thus, both acute bouts of exercise and exercise training appear to modulate complement system proteins. Future research is needed to assess the clinical implications of these changes, for example on the efficacy of monoclonal antibody therapies dependent on CDC.

Oxidizing Americium(III) with Sodium Bismuthate in Acidic Aqueous Solutions.

Historic perspectives describing f-elements as being redox "inactive" are fading. Researchers continue to discover new oxidation states that are not as inaccessible as once assumed for actinides and lanthanides. Inspired by those contributions, we studied americium(III) oxidation in aqueous media under air using NaBiO3(s). We identified selective oxidation of Am3+(aq) to AmO22+(aq) or AmO21+(aq) could be achieved by changing the aqueous matrix identity. AmO22+(aq) formed in H3PO4(aq) (1 M) and AmO21+(aq) formed in dilute HCl(aq) (0.1 M). These americyl products were stable for weeks in solution. Also included is a method to recover 243Am from the americium and bismuth mixtures generated during these studies.

Silencing Itch in human peripheral blood monocytes promotes their differentiation into osteoclasts.

INTRODUCTION: Two clinical case reports of humans with mutations in Itch reported distinct morphological defects such as stunted growth, macrocephaly, and dysmorphic features indicating a role for Itch in bone remodelling. Studies in mice have found that the encoded E3 ubiquitin ligase acts as a negative regulator of osteoclastogenesis, however no studies have investigated whether this is translatable to a human model. EXPERIMENTAL PROCEDURES: Human peripheral blood monocytes were separated from whole blood and grown in M-CSF containing media. Media was later supplemented with RANKL to promote osteoclast differentiation. Transient siRNA-mediated Itch knockdown (si-Itch) in monocytes was verified by qPCR and western blot to confirm reduction in both Itch mRNA and protein respectively. Monocytes were aliquoted onto 96-well plates where confluence and osteoclast formation were analysed using automated cytometry analysis before and after staining for tartrate resistant acid phosphatase activity (TRAP). Cells were also stained with Hoechst33342 to look for multinucleate cells. RESULTS: Cells treated with si-Itch showed an 80% knockdown in Itch mRNA and > 75% reduction in protein. Following the 7-day differentiation period, si-Itch caused a 47% increase in multinucleate cells and a 17% increase in numbers of large cellular bodies and, indicating an overall increase in mature osteoclast formation. CONCLUSIONS: Our preliminary data shows silencing Itch expression increases the potential of primary human monocytes to differentiate into osteoclast-like cells in vitro.

Break-induced telomere synthesis underlies alternative telomere maintenance.

Homology-directed DNA repair is essential for genome maintenance through templated DNA synthesis. Alternative lengthening of telomeres (ALT) necessitates homology-directed DNA repair to maintain telomeres in about 10-15% of human cancers. How DNA damage induces assembly and execution of a DNA replication complex (break-induced replisome) at telomeres or elsewhere in the mammalian genome is poorly understood. Here we define break-induced telomere synthesis and demonstrate that it utilizes a specialized replisome, which underlies ALT telomere maintenance. DNA double-strand breaks enact nascent telomere synthesis by long-tract unidirectional replication. Proliferating cell nuclear antigen (PCNA) loading by replication factor C (RFC) acts as the initial sensor of telomere damage to establish predominance of DNA polymerase δ (Pol δ) through its POLD3 subunit. Break-induced telomere synthesis requires the RFC-PCNA-Pol δ axis, but is independent of other canonical replisome components, ATM and ATR, or the homologous recombination protein Rad51. Thus, the inception of telomere damage recognition by the break-induced replisome orchestrates homology-directed telomere maintenance.

Structural and Ultrastructural Analysis of the Multiple Myeloma Cell Niche and a Patient-Specific Model of Plasma Cell Dysfunction.

Multiple myeloma (MM) is a deadly, incurable malignancy in which antibody-secreting plasma cells (PCs) become neoplastic. Previous studies have shown that the PC niche plays a role cancer progression. Bone marrow (BM) cores from MM and a premalignant condition known as monoclonal gammopathy of unknown significance (MGUS) patients were analyzed with confocal and transmission electron microscopy. The BM aspirates from these patients were used to generate 3D PC cultures. These in vitro cultures were then assayed for the molecular, cellular, and ultrastructural hallmarks of dysfunctional PC at days 1 and 5. In vivo, evidence of PC endoplasmic reticulum stress was found in both MM and MGUS BM; however, evidence of PC autophagy was found only in MM BM. Analysis of in vitro cultures found that MM PC can survive and maintain a differentiated phenotype over an unprecedented 5 days, had higher levels of paraprotein production when compared to MGUS-derived cultures, and showed evidence of PC autophagy as well. Increased fibronectin deposition around PC associated with disease severity and autophagy dysregulation was also observed. 3D cultures constructed from BM aspirates from MGUS and MM patients allow for long-term culture of functional PC while maintaining their distinct morphological phenotypes.

Impact of stress and decision fatigue on parenting practices related to food and physical activity during COVID-19.

BACKGROUND: The COVID-19 pandemic has resulted in substantial disruptions to daily functioning and lifestyle behaviours, with negative health consequences for youth. Parents play a large role in their children's health behaviour; yet changes to parenting behaviours during the pandemic related to food and physical activity remain relatively unexplored. The present study is the first to our knowledge to examine specific changes in American parents' parenting behaviours related to food and physical activity during COVID-19, and potential correlates of such changes, including perceived stress and decision fatigue. METHODS: A total of 140 parents (88.57% female; 88.41% White; 87.59% married; with one to five children) from middle to upper income households completed an online survey assessing demographics, perceived stress (Perceived Stress Scale), decision fatigue (Decision Fatigue Scale) and food and activity parenting behaviour changes during COVID-19. RESULTS: Overall, a greater proportion of parents engaged primarily in positive (57.14%) than negative (22.86%) parenting practices related to food and physical activity during the pandemic. Moderation analyses showed that the negative relation between perceived stress and positive parental behaviour changes was stronger at higher perceived increases in decision fatigue during the pandemic. CONCLUSIONS: In the face of a major public health crisis, adaptive parental responses may emerge, but perceived stress may inhibit such behaviour change. Perceived stress and decision fatigue may represent important explanatory factors in parental health promoting behaviours during times of uncertainty and change.

PFTAIRE Kinase L63 Interactor 1A (Pif1A Protein) Is Required for Actin Cone Movement during Spermatid Individualization in Drosophila melanogaster.

A useful model for determining the mechanisms by which actin and actin binding proteins control cellular architecture is the Drosophila melanogaster process of spermatogenesis. During the final step of spermatogenesis, 64 syncytial spermatids individualized as stable actin cones move synchronously down the axonemes and remodel the membranes. To identify new genes involved in spermatid individualization, we screened a collection of Drosophila male-sterile mutants and found that, in the line Z3-5009, actin cones formed near to the spermatid nuclei but failed to move, resulting in failed spermatid individualization. However, we show by phalloidin actin staining, electron microscopy and immunocytochemical localization of several actin binding proteins that the early cones had normal structure. We sequenced the genome of the Z3-5009 line and identified mutations in the PFTAIRE kinase L63 interactor 1A (Pif1A) gene. Quantitative real-time PCR showed that Pif1A transcript abundance was decreased in the mutant, and a transgene expressing Pif1A fused to green fluorescent protein (GFP) was able to fully rescue spermatid individualization and male fertility. Pif1A-GFP localized to the front of actin cones before initiation of movement. We propose that Pif1A plays a pivotal role in directing actin cone movement.