Interdisciplinary Implementation of a Synoptic Reporting Template for Melanoma Nodal Surveillance Ultrasound.

BACKGROUND: With nodal surveillance increasingly used for sentinel lymph node-positive (SLN+) melanoma following the Second Multicenter Selective Lymphadenectomy Trial (MSLT-II), high-quality nodal ultrasonography (U/S) has become a critical need. Previous work has demonstrated low utilization of MSLT-II U/S criteria to define abnormal lymph nodes requiring intervention or biopsy. To address this gap, an evidence-based synoptic template was designed and implemented in this single-center study. METHODS: Sentinel lymph node-positive patients undergoing nodal surveillance at a tertiary cancer center from July 2017 to June 2023 were identified retrospectively. Ultrasound reporting language was analyzed for MSLT-II criteria reported and clinically actionable recommendations (e.g., normal, abnormal with recommendation for biopsy). Following a multidisciplinary design process, the synoptic template was implemented in January 2023. Postimplementation outcomes were evaluated by using U/S reports and provider surveys. RESULTS: A total of 337 U/S studies were performed on 94 SLN+ patients, with a median of 3 U/S per patient (range 1-12). Among 42 synoptic-eligible U/S performed postimplementation, 32 U/S (76.0%) were reported synoptically. Significant increases were seen in the number of MSLT-II criteria reported (Pre 0.5 ± 0.8 vs. Post 2.5 ± 1.0, p < 0.001), and clinically actionable recommendations for abnormal findings (Pre 64.0% vs. Post 93.0%, p = 0.04). Nearly all surgeon and radiologist survey respondents were "very" or "completely" satisfied with the clinical utility of the synoptic template (90.0%). CONCLUSIONS: Following implementation of a synoptic template, U/S reports were significantly more likely to document MSLT-II criteria and provide an actionable recommendation, increasing usefulness to providers. Efforts to disseminate this synoptic template to other centers are ongoing.

Quantifying and Controlling the Proteolytic Degradation of Cell Adhesion Peptides.

Peptides are widely used within biomaterials to improve cell adhesion, incorporate bioactive ligands, and enable cell-mediated degradation of the matrix. While many of the peptides incorporated into biomaterials are intended to be present throughout the life of the material, their stability is not typically quantified during culture. In this work, we designed a series of peptide libraries containing four different N-terminal peptide functionalizations and three C-terminal functionalizations to better understand how simple modifications can be used to reduce the nonspecific degradation of peptides. We tested these libraries with three cell types commonly used in biomaterials research, including mesenchymal stem/stromal cells (hMSCs), endothelial cells, and macrophages, and quantified how these cell types nonspecifically degraded peptides as a function of terminal amino acid and chemistry. We found that peptides in solution which contained N-terminal amines were almost entirely degraded by 48 h, irrespective of the terminal amino acid, and that degradation occurred even at high peptide concentrations. Peptides with C-terminal carboxylic acids also had significant degradation when cultured with the cells. We found that simple modifications to the termini could significantly reduce or completely abolish nonspecific degradation when soluble peptides were added to cells cultured on tissue culture plastic or within hydrogel matrices, and that functionalizations which mimicked peptide conjugations to hydrogel matrices significantly slowed nonspecific degradation. We also found that there were minimal differences in peptide degradation across cell donors and that sequences mimicking different peptides commonly used to functionalize biomaterials all had significant nonspecific degradation. Finally, we saw that there was a positive trend between RGD stability and hMSC spreading within hydrogels, indicating that improving the stability of peptides within biomaterial matrices may improve the performance of engineered matrices.

Predictors of Paroxysmal Atrial Fibrillation in Patients With a Cryptogenic Stroke: Selecting Patients for Long-Term Rhythm Monitoring.

BACKGROUND: After a cryptogenic stroke, patients will often require prolonged cardiac monitoring; however, the subset of patients who would benefit from long-term rhythm monitoring is not clearly defined. OBJECTIVE: Using significant predictors of AF using age, sex, comorbidities, baseline 12-lead electrocardiogram, short term rhythm monitoring and echocardiogram data, we created a risk score and compared it to previously published risk scores. METHODS: Patients admitted to Montefiore Medical Center between May 2017 and June 2022 with a primary diagnosis of cryptogenic stroke or TIA who underwent long-term rhythm monitoring with an implantable cardiac monitor were retrospectively analyzed. RESULTS: Variables positively associated with a diagnosis of clinically significant atrial fibrillation include age (p < 0.001), race (p = 0.022), diabetes status (p = 0.026), and COPD status (p = 0.012), the presence of atrial runs (p = 0.003), the number of atrial runs per 24 hours (p < 0.001), the total number of atrial run beats per 24 hours (p < 0.001) and the number of beats in the longest atrial run (p < 0.001), LA enlargement (p = 0.007) and at least mild mitral regurgitation (p = 0.009). We created a risk stratification score for our population, termed the "ACL score." The ACL score demonstrated superiority to the CHA2DS2-VASc score and comparability to the C2HEST score for predicting device-detected AF. CONCLUSION: The ACL score enables clinicians to better predict which patients are more likely to be diagnosed with device-detected AF after a cryptogenic stroke.

Dopamine Release in the Nucleus Accumbens Core Encodes the General Excitatory Components of Learning.

Dopamine release in the nucleus accumbens core (NAcC) is generally considered to be a proxy for phasic firing of dopamine neurons in the ventral tegmental area (VTADA). Thus, dopamine release in NAcC is hypothesized to reflect a unitary role in reward prediction error signalling. However, recent studies revealed more diverse roles of dopamine neurons, which support an emerging idea that dopamine regulates learning differently in distinct circuits. To understand whether the NAcC might regulate a unique component of learning, we recorded dopamine release in NAcC while male rats performed a backward conditioning task where a reward is followed by a cue. We used this task because we can delineate different components of learning, which include sensory-specific inhibitory and general excitatory components. Further, we have shown that VTADA neurons are necessary for both the specific and general components of backward associations. Here, we found that dopamine release in NAcC increased to the reward across learning, while reducing to the cue that followed as it became more expected. This mirrors the dopamine prediction error signal seen during forward conditioning and cannot be accounted for temporal-difference reinforcement learning (TDRL). Subsequent tests allowed us to dissociate these learning components and revealed that dopamine release in NAcC reflects the general excitatory component of backward associations, but not their sensory-specific component. These results emphasize the importance of examining distinct functions of different dopamine projections in reinforcement learning.Significance Statement Dopamine regulates reinforcement learning. While it was previously believed that this system contributed to simple value assignment to reward cues, we now know dopamine plays increasingly diverse roles in reinforcement learning. How these diverse roles are achieved in distinct circuits is not fully understood. By using behavioural tasks that examine distinctive components of learning separately, we reveal that NAcC dopamine release contributes to a unique component of learning. Thus, the present study supports a distinct role of NAcC in reinforcement learning, consistent with the idea that different dopamine systems serve different learning functions. Examining the roles of different dopamine projections is an important approach to identify neuronal mechanisms underlying the reinforcement-learning deficits observed in schizophrenia and drug addiction.

Pediatric sex estimation using AI-enabled ECG analysis: influence of pubertal development.

AI-enabled ECGs have previously been shown to accurately predict patient sex in adults and correlate with sex hormone levels. We aimed to test the ability of AI-enabled ECGs to predict sex in the pediatric population and study the influence of pubertal development. AI-enabled ECG models were created using a convolutional neural network trained on pediatric 10-second, 12-lead ECGs. The first model was trained de novo using pediatric data. The second model used transfer learning from a previously validated adult data-derived algorithm. We analyzed the first ECG from 90,133 unique pediatric patients (aged ≤18 years) recorded between 1987-2022, and divided the cohort into training, validation, and testing datasets. Subgroup analysis was performed on prepubertal (0-7 years), peripubertal (8-14 years), and postpubertal (15-18 years) patients. The cohort was 46.7% male, with 21,678 prepubertal, 26,740 peripubertal, and 41,715 postpubertal children. The de novo pediatric model demonstrated 81% accuracy and an area under the curve (AUC) of 0.91. Model sensitivity was 0.79, specificity was 0.83, positive predicted value was 0.84, and the negative predicted value was 0.78, for the entire test cohort. The model's discriminatory ability was highest in postpubertal (AUC = 0.98), lower in the peripubertal age group (AUC = 0.91), and poor in the prepubertal age group (AUC = 0.67). There was no significant performance difference observed between the transfer learning and de novo models. AI-enabled interpretation of ECG can estimate sex in peripubertal and postpubertal children with high accuracy.

The Micromechanical Environment of the Impinged Achilles Tendon.

Although tendon predominantly experiences longitudinal tensile forces, transverse forces due to impingement from bone are implicated in both physiological and pathophysiological processes. However, prior studies have not characterized the micromechanical strain environment in the context of tendon impingement. To address this knowledge gap, mouse hindlimb explants are imaged on a multiphoton microscope, and image stacks of the same population of tendon cells are obtained in the Achilles tendon before and after dorsiflexion-induced impingement by the heel bone. Based on the acquired images, multiaxial strains are measured at the extracellular matrix (ECM), pericellular matrix (PCM), and cell scales. Impingement generated substantial transverse compression at the matrix-scale, which led to longitudinal stretching of cells, increased cell aspect ratio, and enormous volumetric compression of the PCM. These experimental results are corroborated by a finite element model, which further demonstrated that impingement produces high cell surface stresses and strains that greatly exceed those brought about by longitudinal tension. Moreover, in both experiments and simulations, impingement-generated microscale stresses and strains are highly dependent on initial cell-cell gap spacing. Identifying factors that influence the microscale strain environment generated by impingement could contribute to a more mechanistic understanding of impingement-induced tendinopathies.

Safety-netting advice documentation out-of-hours: a retrospective cohort from 2013 to 2020.

BACKGROUND: Providing safety-netting advice (SNA) in out-of-hours primary care is a recognised standard of safe care but it is not known how frequently this occurs in practice. AIM: Assess the frequency and type of SNA documented in out-of-hours primary care and explore factors associated with its presence. DESIGN AND SETTING: Retrospective cohort using the Birmingham Out-of-hours General Practice Research Database. METHOD: A stratified sample of 30 adult consultation records per month from July 2013 to February 2020 were assessed using a safety-netting coding tool. Associations were tested using linear and logistic regression. RESULTS: The overall frequency of SNA per consultation was 78.0%, increasing from 75.7% (2014) to 81.5% (2019). The proportion of specific SNA and the average number of symptoms patients were told to look out for increased with time. The most common symptom to look out for was if the patients' condition worsened followed by if their symptoms persisted, but only one in five consultations included a time-frame to reconsult for persistent symptoms. SNA was more frequently documented in face-to-face treatment-centre encounters compared to telephone-consultations (Odds Ratio [OR]=1.77, p=0.02), for possible infections (OR=1.53, p=0.006), and less frequently for mental (vs. physical) health consultations (OR=0.33, p=0.002) and where follow-up was planned (OR=0.34, p<0.001). CONCLUSION: The frequency of SNA documented in OOH was higher than previously reported during in-hours care. Over time, the frequency of SNA and proportion that contained specific advice increased, however this study highlights potential consultations where SNA could be improved, such as mental health and telephone consultations.

Understanding Public Perceptions of Nipple and Scar Characteristics After Chest Wall Masculinization Surgery.

BACKGROUND: Surgical chest masculinization procedures, especially gender-affirming top surgery (GATS), are becoming increasingly prevalent in the USA. While a variety of surgical techniques have been established as both safe and effective, there is limited research examining ideal aesthetic nipple appearance and incision scar pattern. This study employs patient images to understand the public's perception on top surgery outcomes when adjusting for BMI ranges and Fitzpatrick skin types. METHODS: Images from RealSelf modified via Adobe Photoshop depicted various scar types and nipple-areolar complex (NAC) sizes/positions. A Qualtrics survey was distributed utilizing Amazon Mechanical Turk. Statistical analysis was performed through JMP Pro 17 for ordinal and categorical values, with a p value less than or equal to 0.05 statistically significant. RESULTS: A moderately sized and laterally placed NAC was preferred. A transverse scar that resembles the pectoral border between the level of the inframammary fold and pectoral insertion was deemed most masculine and aesthetic. Majority of results demonstrated that this is unaffected by Fitzpatrick skin types. Increased BMI images impacted public preferences, as a nipple placed farther from the transverse incision (p = 0.04) and a transverse scar position closer to the IMF was preferred in higher BMI patients. CONCLUSIONS: An understanding of the most popular NAC and scar choices, as well as how these factors may differ when considering a Fitzpatrick skin type or BMI categorization was attained. This validates the importance of patient-centered approach when employing surgical techniques in GATS. Future studies intend to obtain reports from actual patients considering GATS. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable.

Exploring the effects of taurolidine on tumor weight and microvessel density in a murine model of osteosarcoma.

Background: Osteosarcoma is the most common malignant primary bone tumor. The prognosis for patients with disseminated disease remains very poor despite recent advancements in chemotherapy. Moreover, current treatment regimens bear a significant risk of serious side effects. Thus, there is an unmet clinical need for effective therapies with improved safety profiles. Taurolidine is an antibacterial agent that has been shown to induce cell death in different types of cancer cell lines. Methods: In this study, we examined both the antineoplastic and antiangiogenic effects of taurolidine in animal models of osteosarcoma. K7M2 murine osteosarcoma cells were injected, both intramuscular and intraperitoneal, into 60 BALB/c mice on day zero. Animals were then randomized to receive treatment with taurolidine 2% (800 mg/kg), taurolidine 1% (400 mg/kg), or NaCl 0.9% control for seven days by intravenous or intraperitoneal administration. Results: After 35 days, mice were euthanized, and the tumors were harvested for analysis. Eighteen mice were excluded from the analysis due to complications. Body weight was significantly lower in the 2% taurolidine intraperitoneal treatment group from day 9 to 21, consistent with elevated mortality in this group. Intraperitoneal tumor weight was significantly lower in the 1% (p = 0.003) and 2% (p = 0.006) intraperitoneal taurolidine treatment groups compared to the control. No antineoplastic effects were observed on intramuscular tumors or for intravenous administration of taurolidine. There were no significant differences in microvessel density or mitotic rate between treatment groups. Reduced body weight and elevated mortality in the 2% taurolidine intraperitoneal group suggest that the lower 1% dose is preferable. Conclusions: In conclusion, there is no evidence of antiangiogenic activity, and the antitumor effects of taurolidine on osteosarcoma observed in this study are limited. Moreover, its toxic profile grants further evaluation. Given these observations, further research is necessary to refine the use of taurolidine in osteosarcoma treatment.

Cannabis in Combat Sports: position statement of the association of ringside physicians.

and ARP Position StatementBased on the available body of scientific evidence and with the goals of promoting safety of combat sports athletes and striving for the advancement of clean sport, the Association of Ringside Physicians recommends the following regarding cannabis:●Use of marijuana or synthetic cannabinoids by combat sports athletes is discouraged due to unproven benefits and many known adverse effects. Acute use can impair cognition and complex motor function, which likely leads to reduced performance in combat sports. Chronic use can increase risk for heart and lung disease, several cancers, schizophrenia, and can reduce testosterone in men and impair fertility. Benefits from cannabis in most contexts, including athletic performance, have not been proven.●Use of topical purified CBD is neither encouraged nor discouraged.●Since acute cannabis intoxication can impair complex cognitive and motor function, any athlete suspected of acute intoxication at the time of competition - based on clinical judgment - should be banned from that competition.●Wide-scale regulation of cannabis based on quantitative testing has limited usefulness in combat sports, for the following reasons:○Cannabis is not ergogenic and is likely ergolytic.○Concentrations in body fluids correlate poorly with clinical effects and timing of use.○Access to testing resources varies widely across sporting organizations.

Kelvin-Helmholtz instability as one of the key features for fast and efficient emulsification by hydrodynamic cavitation.

The paper investigates the oil-water emulsification process inside a micro-venturi channel. More specifically, the possible influence of Kelvin-Helmholtz instability on the emulsification process. High-speed visualizations were conducted inside a square venturi constriction with throat dimensions of 450 µm by 450 µm, both under visible light and X-Rays. We show that cavity shedding caused by the instability results in the formation of several cavity vortices. Their rotation causes the deformation of the oil stream into a distinct wave-like shape, combined with fragmentation into larger drops due to cavitation bubble collapse. Later on, the cavity collapse further disperses the larger drops into a finer emulsion. Thus, it turns out that the Kelvin-Helmholtz instability is similarly characteristic for hydrodynamic cavitation emulsification inside a microchannel as is the Rayleigh-Taylor instability for acoustically driven emulsion formation.

Irritability in young people with copy number variants associated with neurodevelopmental disorders (ND-CNVs).

A range of rare mutations involving micro-deletion or -duplication of genetic material (copy number variants (CNVs)) have been associated with high neurodevelopmental and psychiatric risk (ND-CNVs). Irritability is frequently observed in childhood neurodevelopmental conditions, yet its aetiology is largely unknown. Genetic variation may play a role, but there is a sparsity of studies investigating the presentation of irritability in young people with ND-CNVs. This study aimed to investigate whether there is a difference in irritability in young people with rare ND-CNVs compared to those without ND-CNVs, and to what extent irritability is associated with psychiatric diagnoses and cognitive ability (IQ). Irritability and broader psychopathology were assessed in 485 young people with ND-CNVs and 164 sibling controls, using the child and adolescent psychiatric assessment. Autism was assessed using the social communication questionnaire, and intelligence quotient (IQ) by the Wechsler abbreviated scale of intelligence. Fifty four percent of young people with ND-CNVs met the threshold for irritability; significantly more than controls (OR = 3.77, CI = 3.07-7.90, p = 5.31 × 10-11). When controlling for the presence of other psychiatric comorbidities, ND-CNV status was still associated with irritability. There was no evidence for a relationship between irritability and IQ. Irritability is an important aspect of the clinical picture in young people with ND-CNVs. This work shows that genetic variation is associated with irritability in young people with ND-CNVs, independent of psychiatric comorbidities or IQ impairment. Clinicians should be aware of this increased risk to inform management and interventions.

Beyond Rubik: The Embodiment-Presence-Interactivity Cube applied to exercise.

Evidence-based interventions are needed to promote engagement in physical activity. Audio-visual stimuli are frequently employed to enhance the exercise experience. Nonetheless, there is a paucity of research that examines the qualities of technological devices that are employed. Using the Embodiment-Presence-Interactivity Cube (Flavián et al., 2019) as a guiding conceptual framework, the aim of this registered report was to examine how each dimension of the cube (i.e., embodiment, presence and interactivity) influenced a range of exercise-related affective and perceptual variables. A counterbalanced within-subjects design was employed (N = 24). Participants completed 20-min exercise bouts on a cycle ergometer under four conditions: Television, augmented reality, 360° video and virtual reality. A repeated-measures ANOVA indicated a significant Condition × Timepoint interaction for affective valence (p = 0.046), with greater embodiment offered by technological devices leading to more positive responses. Analyses also indicated main effects of condition for exercise enjoyment, remembered pleasure and forecasted pleasure, with greater presence of technological devices leading to more positive responses. Technologies that combine high levels of embodiment, presence and interactivity (e.g., virtual reality) appear to yield several benefits in terms of in-task (e.g., affective valence) and post-task (e.g., remembered pleasure) responses for exercise conducted at ventilatory threshold.

Comparing Collagenase and Tissue Subcision for Cellulite Treatment of the Buttock and Thigh Regions: A Systematic Review and Meta-analysis.

Background: In this systematic review, we assessed the therapeutic efficacy and safety of Clostridium histolyticum collagenase (CCH) and tissue subcision (TS) for treating cellulite, which ranges from subtle to pronounced lesions. Methods: A systematic review was performed following PRISMA guidelines for CCH and TS treatment to the thigh and gluteal regions. A proportion meta-analysis was then conducted using Stata statistical software. Results: A total of 14 studies were incorporated into the final analysis. Nine focused on TS and five on CCH injection, collectively reporting outcomes for 1254 patients. Of these, 465 received CCH injection and 789 underwent subcision. For bruising, rates were 89% [95% confidence interval (CI), 71%-96%] with CCH injection and 99% (95% CI, 85%-99%) for subcision; pain requiring analgesic was reported at 74% (95% CI, 55%-87%) for CCH and 60% (95% CI, 43%-76%) for subcision; both showed induration at 7% (95% CI, 5%-11% for CCH, 95% CI, 2%-25% for subcision), whereas skin discoloration was higher post-CCH injection at 16% (95% CI, 10%-26%) compared with 7% (95% CI, 5%-10%) postsubcision. Conclusions: Both CCH and TS seem effective treatments for cellulite. However, upon evaluating the adverse outcomes between the two modalities, subcision demonstrated a higher incidence of bruising, albeit similar rates of induration compared with CCH injection. Conversely, the CCH injection group manifested a higher propensity for pain requiring analgesia and notably exhibited increased instances of skin discoloration compared with their subcision patient group. Further standardized research is crucial for more informed cellulite treatment decisions and for comparing efficacy, safety, and cost-effectiveness between TS and CCH.

Expanding salivary biomarker detection by creating a synthetic neuraminic acid sensor via chimeragenesis.

Accurate and timely diagnosis of oral squamous cell carcinoma (OSCC) is crucial in preventing its progression to advanced stages with a poor prognosis. As such, the construction of sensors capable of detecting previously established disease biomarkers for the early and non-invasive diagnosis of this and many other conditions has enormous therapeutic potential. In this work, we apply synthetic biology techniques for the development of a whole-cell biosensor (WCB) that leverages the physiology of engineered bacteria in vivo to promote the expression of an observable effector upon detection of a soluble molecule. To this end, we have constructed a bacterial strain expressing a novel chimeric transcription factor (Sphnx) for the detection of N-acetylneuraminic acid (Neu5Ac), a salivary biomolecule correlated with the onset of OSCC. This WCB serves as the proof-of-concept of a platform that can eventually be applied to clinical screening panels for a multitude of oral and systemic medical conditions whose biomarkers are present in saliva.

A stargate mechanism of Microviridae genome delivery unveiled by cryogenic electron tomography.

Single-stranded DNA bacteriophages of the Microviridae family are major components of the global virosphere. Microviruses are highly abundant in aquatic ecosystems and are prominent members of the mammalian gut microbiome, where their diversity has been linked to various chronic health disorders. Despite the clear importance of microviruses, little is known about the molecular mechanism of host infection. Here, we have characterized an exceptionally large microvirus, Ebor, and provide crucial insights into long-standing mechanistic questions. Cryogenic electron microscopy of Ebor revealed a capsid with trimeric protrusions that recognise lipopolysaccharides on the host surface. Cryogenic electron tomography of the host cell colonized with virus particles demonstrated that the virus initially attaches to the cell via five such protrusions, located at the corners of a single pentamer. This interaction triggers a stargate mechanism of capsid opening along the 5-fold symmetry axis, enabling delivery of the virus genome. Despite variations in specific virus-host interactions among different Microviridae family viruses, structural data indicate that the stargate mechanism of infection is universally employed by all members of the family. Startlingly, our data reveal a mechanistic link for the opening of relatively small capsids made out of a single jelly-roll fold with the structurally unrelated giant viruses.

Transcobalamin receptor antibodies in autoimmune vitamin B12 central deficiency.

Vitamin B12 is critical for hematopoiesis and myelination. Deficiency can cause neurologic deficits including loss of coordination and cognitive decline. However, diagnosis relies on measurement of vitamin B12 in the blood, which may not accurately reflect the concentration in the brain. Using programmable phage display, we identified an autoantibody targeting the transcobalamin receptor (CD320) in a patient with progressive tremor, ataxia, and scanning speech. Anti-CD320 impaired cellular uptake of cobalamin (B12) in vitro by depleting its target from the cell surface. Despite a normal serum concentration, B12 was nearly undetectable in her cerebrospinal fluid (CSF). Immunosuppressive treatment and high-dose systemic B12 supplementation were associated with increased B12 in the CSF and clinical improvement. Optofluidic screening enabled isolation of a patient-derived monoclonal antibody that impaired B12 transport across an in vitro model of the blood-brain barrier (BBB). Autoantibodies targeting the same epitope of CD320 were identified in seven other patients with neurologic deficits of unknown etiology, 6% of healthy controls, and 21.4% of a cohort of patients with neuropsychiatric lupus. In 132 paired serum and CSF samples, detection of anti-CD320 in the blood predicted B12 deficiency in the brain. However, these individuals did not display any hematologic signs of B12 deficiency despite systemic CD320 impairment. Using a genome-wide CRISPR screen, we found that the low-density lipoprotein receptor serves as an alternative B12 uptake pathway in hematopoietic cells. These findings dissect the tissue specificity of B12 transport and elucidate an autoimmune neurologic condition that may be amenable to immunomodulatory treatment and nutritional supplementation.

CaMKII autophosphorylation is the only enzymatic event required for synaptic memory.

Ca2+/calmodulin (CaM)-dependent kinase II (CaMKII) plays a critical role in long-term potentiation (LTP), a well-established model for learning and memory through the enhancement of synaptic transmission. Biochemical studies indicate that CaMKII catalyzes a phosphotransferase (kinase) reaction of both itself (autophosphorylation) and of multiple downstream target proteins. However, whether either type of phosphorylation plays any role in the synaptic enhancing action of CaMKII remains hotly contested. We have designed a series of experiments to define the minimal requirements for the synaptic enhancement by CaMKII. We find that autophosphorylation of T286 and further binding of CaMKII to the GluN2B subunit are required both for initiating LTP and for its maintenance (synaptic memory). Once bound to the NMDA receptor, the synaptic action of CaMKII occurs in the absence of target protein phosphorylation. Thus, autophosphorylation and binding to the GluN2B subunit are the only two requirements for CaMKII in synaptic memory.

Iron status is associated with tibial structure and vitamin D metabolites in healthy young men.

The influence of iron on collagen synthesis and vitamin D metabolism has implications for bone health. This cross-sectional observational study investigated associations between markers of iron status and tibial structure, vitamin D metabolites, and circulating biochemical markers of bone metabolism in young healthy men. A total of 343 male British Army recruits participated (age 22 ± 3 y, height 1.77 ± 0.06 m, body mass 75.5 ± 10.1 kg). Circulating biochemical markers of iron status, vitamin D metabolites, and bone metabolism, and tibial structure and density by high-resolution peripheral quantitative computed tomography scans (HRpQCT) were measured in participants during week 1 of basic military training. Associations between markers of iron status and HRpQCT outcomes, bone metabolism, and vitamin D metabolites were tested, controlling for age, height, lean body mass, and childhood exercise volume. Higher ferritin was associated with higher total, trabecular, and cortical volumetric bone mineral density, trabecular volume, cortical area and thickness, stiffness, and failure load (all p ≤ 0.037). Higher soluble transferrin receptor (sTfR) was associated with lower trabecular number, and higher trabecular thickness and separation, cortical thickness, and cortical pore diameter (all p ≤ 0.033). Higher haemoglobin was associated with higher cortical thickness (p = 0.043). Higher ferritin was associated with lower ßCTX, PINP, total 25(OH)D, and total 24,25(OH)2D, and higher 1,25(OH)2D:24,25(OH)2D ratio (all p ≤ 0.029). Higher sTfR was associated with higher PINP, total 25(OH)D, and total 24,25(OH)2D (all p ≤ 0.025). The greater density, size, and strength of the tibia, and lower circulating concentrations of markers of bone resorption and formation with better iron stores (higher ferritin) are likely as a result of the direct role of iron in collagen synthesis.