Pediatric Pharmacology for the Primary Care Provider: Advances and Limitations.

Despite >1 in 5 children taking prescription drugs in the United States, off-label drug use is common. To increase the study of drugs in children, regulatory bodies have enacted legislation to incentivize and require pediatric drug studies. As a result of this legislation, novel trial approaches, and an increase in personnel with pediatric expertise, there have been numerous advancements in pediatric drug development. With this review, we aim to highlight developments in pediatric pharmacology over the past 6 years for the most common disease processes that may be treated pharmacologically by the pediatric primary care provider. Using information extracted from label changes between 2018 and 2023, the published literature, and Clinicaltrials.gov, we discuss advances across multiple therapeutic areas relevant to the pediatric primary care provider, including asthma, obesity and related disorders, mental health disorders, infections, and dermatologic conditions. We highlight instances in which new drugs have been developed on the basis of a deeper mechanistic understanding of illness and instances in which labels have been expanded in older drugs on the basis of newly available data. We then consider additional factors that affect pediatric drug use, including cost and nonpharmacologic therapies. Although there is work to be done, efforts focused on pediatric-specific drug development will increase the availability of evidence-based, labeled guidance for commonly prescribed drugs and improve outcomes through the safe and effective use of drugs in children.

Judicial Opinion 130.

Opinion 130 deals with a Request for an Opinion asking the Judicial Commission to clarify whether the genus name Rhodococcus Zopf 1891 (Approved Lists 1980) is illegitimate. The Request is approved and an answer is given. The name Rhodococcus Zopf 1891 (Approved Lists 1980) is illegitimate because it is a later homonym of the validly published cyanobacterial name Rhodococcus Hansgirg 1884. The Judicial Commission also clarifies that it has the means to resolve such cases by conserving a name over an earlier homonym. It is concluded that the name Rhodococcus Zopf 1891 (Approved Lists 1980) is significantly more important than the name Rhodococcus Hansgirg 1884 and therefore the former is conserved over the latter. This makes the name Rhodococcus Zopf 1891 (Approved Lists 1980) legitimate.

Trans-synaptic association of vesicular zinc transporter 3 and Shank3 supports synapse-specific dendritic spine structure and function in mouse auditory cortex.

Shank3 is a synaptic scaffolding protein that assists in tethering and organizing structural proteins and glutamatergic receptors in the postsynaptic density of excitatory synapses. The localization of Shank3 at excitatory synapses and the formation of stable Shank3 complexes is regulated by the binding of zinc to the C-terminal sterile-alpha-motif (SAM) domain of Shank3. Mutations in the SAM domain of Shank3 result in altered synaptic function and morphology, and disruption of zinc in synapses that express Shank3 leads to a reduction of postsynaptic proteins important for synaptic structure and function. This suggests that zinc supports the localization of postsynaptic proteins via Shank3. Many regions of the brain are highly enriched with free zinc inside glutamatergic vesicles at presynaptic terminals. At these synapses, zinc transporter 3 (ZnT3) moves zinc into vesicles where it is co-released with glutamate. Alterations in ZnT3 are implicated in multiple neurodevelopmental disorders, and ZnT3 knock-out (KO) mice - which lack synaptic zinc - show behavioral deficits associated with autism spectrum disorder and schizophrenia. Using male and female mice, we show that ZnT3 KO mice have smaller dendritic spines and miniature excitatory postsynaptic current amplitudes than wildtype (WT) mice in the auditory cortex. Additionally, spine size deficits in ZnT3 KO mice are restricted to synapses that express Shank3. In WT mice, synapses that express both Shank3 and ZnT3 have larger spines compared to synapses that express Shank3 but not ZnT3. Together these findings suggest a mechanism whereby presynaptic ZnT3-dependent zinc supports postsynaptic structure and function via Shank3 in a synapse-specific manner.Significance Statement Shank3 is a scaffolding protein that assists in the organization of glutamatergic receptors in the postsynaptic density of excitatory synapses in the brain. The structure and function of Shank3 is regulated by zinc ions. Specifically, zinc allows Shank3 to form tight sheets that assist in stabilizing the postsynaptic density. Zinc packaged by the zinc transporter ZnT3 which is released from presynaptic terminals may contribute to the function of Shank3. In this study, we find an association between ZnT3, Shank3, synaptic strength, and spine size, suggesting that zinc released from presynaptic terminals supports dendritic spine structure and function via interactions with Shank3.

High Blood Pressure in Children Aged 3 to 12 Years Old With Overweight or Obesity.

Objective: (1) To describe the prevalence of high blood pressure (BP) and the association with BMI in young children with overweight/obesity; (2) to evaluate the accuracy of a single high BP to diagnose sustained hypertension over three visits. Methods: We used pre-intervention data from the Improving Pediatric Obesity Practice Using Prompts (iPOP-UP) trial. We included children aged 3-12 years with BMI ≥85th percentile at well-visits in 2019-2021 at 84 primary care practices in 3 US health systems in the Northeast, Midwest, and South. BP percentiles were calculated from the first visit with BP recorded during the study period. Hypertensive-range BP was defined by the 2017 American Academy of Pediatrics guideline. We tested the association between BMI classification and hypertensive BP using multivariable logistic regression. Results: Of 78,280 children with BMI ≥85th percentile, 76,214 (97%) had BP recorded during the study period (mean 7.4 years, 48% female, 53% with overweight, and 13% with severe obesity). The prevalence of elevated or hypertensive BP was 31%, including 27% in children with overweight and 33%, 39%, and 49% with class I, II, and III obesity, respectively. Higher obesity severity was associated with higher odds of hypertensive BP in the multivariable model. Stage 2 hypertensive BP at the initial visit had specificity of 99.1% (95% confidence interval 98.9-99.3) for detecting sustained hypertension over ≥3 visits. Conclusions: High BP is common in 3- to 12-year-olds with overweight/obesity, with higher obesity severity associated with greater hypertension. Children with overweight/obesity and stage 2 BP are likely to have sustained hypertension and should be prioritized for evaluation. Trial Registration: ClinicalTrials.gov Identifier: NCT05627011.

Amplification of positivity for depression and anxiety: Neural prediction of treatment response.

Psychosocial treatments targeting the positive valence system (PVS) in depression and anxiety demonstrate efficacy in enhancing positive affect (PA), but response to treatment varies. We examined whether individual differences in neural activation to positive and negative valence incentive cues underlies differences in benefitting from a PVS-targeted treatment. Individuals with clinically elevated depression and/or anxiety (N = 88, ages 18 to 55) participated in one of two randomized, waitlist-controlled trials of Amplification of Positivity (AMP; NCT02330627, NCT03196544), a cognitive and behavioral intervention targeting the PVS. Participants completed a monetary incentive delay (MID) task during fMRI acquisition at baseline measuring neural activation to the possibility of gaining or losing money. Change in PA from before to after treatment was assessed using the Positive and Negative Affect Schedule. No significant associations were observed between baseline neural activation during gain anticipation and AMP-related changes in PA in regions of interest (striatum and insula) or whole-brain analyses. However, higher baseline striatal and insula activation during loss anticipation was associated with greater increases in PA post-AMP. This study provides preliminary evidence suggesting neural reactivity to negative valence cues may inform who stands to benefit most from treatments targeting the PVS.

Architecture and functions of stomatal cell walls in eudicots and grasses.

BACKGROUND: Like all plant cells, the guard cells of stomatal complexes are encased in cell walls that are composed of diverse, interacting networks of polysaccharide polymers. The properties of these cell walls underpin the dynamic deformations that occur in guard cells as they expand and contract to drive the opening and closing of the stomatal pore, the regulation of which is critical for photosynthesis and water transport in plants. SCOPE: Our understanding of how cell wall mechanics are influenced by the nanoscale assembly of cell wall polymers in guard cell walls, how this architecture changes over stomatal development, maturation, and aging, and how the cell walls of stomatal guard cells might be tuned to optimize stomatal responses to dynamic environmental stimuli is still in its infancy. CONCLUSION: In this review, we discuss advances in our ability to experimentally probe and quantitatively model the structure and dynamics of guard cell walls across a range of plant species, highlighting new ideas and exciting opportunities for further research into these actively moving plant cells.

Glycosylated Polyhydroxyproline Is a Potent Antifreeze Molecule.

Molecules that inhibit the growth of ice crystals are highly desirable for applications in building materials, foods, and agriculture. Antifreezes are particularly essential in biomedicine for tissue banking, yet molecules currently in use have known toxic effects. Antifreeze glycoproteins have evolved naturally in polar fish species living in subzero climates, but practical issues with collection and purification have limited their commercial use. Here, we present a synthetic strategy using polymerization of amino acid N-carboxyanhydrides to produce polypeptide mimics of these potent natural antifreeze proteins. We investigated a set of mimics with varied structural properties and identified a glycopolypeptide with potent ice recrystallization inhibition properties. We optimized for molecular weight, characterized their conformations, and verified their cytocompatibility in a human cell line. Overall, we present a material that will have broad applications as a biocompatible antifreeze.

A Mixed-Methods Evaluation of a Project ECHO Program for the Evidence-Based Management of Sickle Cell Disease.

Sickle cell disease (SCD) is a group of chronic, genetic disorders of the red blood cells with significant gaps in access to evidence-based clinical care. Sickle Treatment and Outcomes Research in the Midwest (STORM), a provider network, utilized Project ECHO (Extension for Community Health Outcomes), a telementoring model, to deliver evidence-based education about SCD management. The purpose of this mixed-methods study is to evaluate the utility of Project ECHO as an educational strategy for healthcare providers treating children and adults with SCD. Annual evaluations were administered to STORM TeleECHO participants from 2016 to 2021. Survey data showed a statistically significant change in self-reported provider confidence in the ability to provide care for adult patients with SCD; identify suitable candidates for disease-modifying therapies; and confidence to prescribe disease-modifying therapies. Participants who attended at least 10 sessions were invited to participate in a semi-structured interview. Qualitative data were analyzed using thematic analysis and several themes emerged about the benefits, including (1) increased confidence, (2) integrated best-practice care, (3) connection to provider network and access to experts, (4) high-quality educational presentations and (5) opportunities for collaboration and a sense of community. This suggests that Project ECHO is accessible and leads to increased confidence in providers caring for individuals with SCD. Overall, participant knowledge gains successfully demonstrated the utility of Project ECHO as an educational resource for providers.

Trends in Arthritis Prevalence and Associated Chronic Health Indicators Among Adults: Insights From the Behavioral Risk Factor Surveillance System (BRFSS) Database.

Background Arthritis is a prevalent, chronic condition with significant implications for morbidity and healthcare utilization. Understanding trends in arthritis prevalence and associated chronic health indicators is vital for informing public health interventions and healthcare policies. Objective This retrospective study aimed to analyze trends in arthritis prevalence and associated chronic health indicators among adults using data from the Behavioral Risk Factor Surveillance System (BRFSS) database. Methods This retrospective study utilized data from the BRFSS database covering 2019 to 2022. Participants included United States adults aged 18 years and older who completed BRFSS surveys during the specified period. Primary variables included arthritis prevalence and its correlation with chronic health indicators and demographics. Data collection involved standardized telephone questionnaires administered annually, with rigorous attention to data quality and consistency. Prevalence estimates were calculated using weighted proportions, and statistical analysis utilized analysis of variance (ANOVA). Results The study revealed relatively stable arthritis prevalence over the study period, with notable demographic variations. Arthritis prevalence remained stable (2019: 43.3%, 2021: 42.5%). Females consistently had higher rates than males (2019: 45%, 2021: 44.9%). Activity limitation, joint pain, and work limitation were more prevalent in arthritis patients. White, non-Hispanic individuals had higher rates than other groups. Physical inactivity increased from 2019 (29.4%) to 2022 (72.4%), particularly in males. Counseling for physical activity was lower in males. Targeted interventions are needed to address these disparities and improve arthritis management. Conclusion This study provides insights into trends in arthritis prevalence and associated chronic health indicators among United States adults. The findings underscore the importance of considering demographic factors in arthritis prevention and management strategies. Targeted interventions promoting physical activity counseling, particularly among high-risk populations, are warranted to address the rising trend of physical inactivity among individuals with arthritis.

User-Centered Framework for Implementation of Technology (UFIT): Development of an Integrated Framework for Designing Clinical Decision Support Tools Packaged With Tailored Implementation Strategies.

BACKGROUND: Electronic health record-based clinical decision support (CDS) tools can facilitate the adoption of evidence into practice. Yet, the impact of CDS beyond single-site implementation is often limited by dissemination and implementation barriers related to site- and user-specific variation in workflows and behaviors. The translation of evidence-based CDS from initial development to implementation in heterogeneous environments requires a framework that assures careful balancing of fidelity to core functional elements with adaptations to ensure compatibility with new contexts. OBJECTIVE: This study aims to develop and apply a framework to guide tailoring and implementing CDS across diverse clinical settings. METHODS: In preparation for a multisite trial implementing CDS for pediatric overweight or obesity in primary care, we developed the User-Centered Framework for Implementation of Technology (UFIT), a framework that integrates principles from user-centered design (UCD), human factors/ergonomics theories, and implementation science to guide both CDS adaptation and tailoring of related implementation strategies. Our transdisciplinary study team conducted semistructured interviews with pediatric primary care clinicians and a diverse group of stakeholders from 3 health systems in the northeastern, midwestern, and southeastern United States to inform and apply the framework for our formative evaluation. RESULTS: We conducted 41 qualitative interviews with primary care clinicians (n=21) and other stakeholders (n=20). Our workflow analysis found 3 primary ways in which clinicians interact with the electronic health record during primary care well-child visits identifying opportunities for decision support. Additionally, we identified differences in practice patterns across contexts necessitating a multiprong design approach to support a variety of workflows, user needs, preferences, and implementation strategies. CONCLUSIONS: UFIT integrates theories and guidance from UCD, human factors/ergonomics, and implementation science to promote fit with local contexts for optimal outcomes. The components of UFIT were used to guide the development of Improving Pediatric Obesity Practice Using Prompts, an integrated package comprising CDS for obesity or overweight treatment with tailored implementation strategies. TRIAL REGISTRATION: ClinicalTrials.gov NCT05627011; https://clinicaltrials.gov/study/NCT05627011.

Validation of the Approach-Avoidance Temperament Questionnaire in Individuals with Anxiety and Depression.

The Approach-Avoidance Temperament Questionnaire (ATQ) is a well-established measure assessing heightened sensitivity and reactivity to reward/positive stimuli (approach temperament) and to punishment/negative stimuli (avoidance temperament). These basic dimensions of personality are believed to be important for understanding the etiology and maintenance of anxiety and depressive disorders. Despite the ATQ's potential utility in clinical psychology research, its psychometric properties and factor structure have yet to be examined in a psychiatric sample. The aims of the present study were to 1) conduct confirmatory factor analysis to replicate the ATQ's factor structure in individuals diagnosed with an anxiety or depressive disorder (N = 244), 2) assess internal consistency and convergent and divergent validity, and 3) explore differences in approach and avoidance temperaments in individuals with versus without a diagnosis of anxiety or depression. Results confirmed the original two-factor structure of the ATQ in a clinical sample, with approach and avoidance temperaments representing orthogonal dimensions. The measure demonstrated strong internal consistency, convergent and divergent validity, and predictive validity. Individuals with anxiety and depression scored higher on avoidance items and lower on approach items compared to those without clinical diagnoses. This study supports the use of the ATQ in clinical populations.

Geographic Progression of Infant Respiratory Syncytial Virus Associated Bronchiolitis Across the United States Before and Since the Onset of COVID-19: Results From Four Health Systems, 2015-2023.

BACKGROUND: Respiratory syncytial virus (RSV) is a substantial cause of infant morbidity and mortality due to seasonal peaks of bronchiolitis across the United States. Clinical and viral surveillance plays a pivotal role in helping hospital systems prepare for expected surges in RSV bronchiolitis. Existing surveillance efforts have shown a geographic pattern of RSV positivity across the United States, with cases typically starting in the southeast and spreading north and west. Public health measures implemented due to the COVID-19 pandemic disrupted viral transmission across the nation and altered the expected seasonality of RSV. The impact of these changes on the geographic progression of infant RSV bronchiolitis across the United States has not been described. METHODS: Here, we used clinical and viral surveillance data from four health care systems located in different regions of the United States to describe the geographic progression of infant RSV bronchiolitis across the country from 2015 to 2023. RESULTS: Prior to widespread circulation of SARS-CoV-2, infant RSV bronchiolitis followed an established geographic pattern associated with seasonal epidemics originating in Florida and spreading north (North Carolina and New York) and later westward (Nevada). Although public health and social measures implemented during the COVID-19 pandemic disrupted the seasonality of RSV disease, infant RSV bronchiolitis epidemics progressed across the nation in a pattern identical to the prepandemic era. CONCLUSIONS: Our findings highlight the importance of ongoing clinical and viral surveillance to optimally track the onset of RSV epidemics and allow health care systems to prepare for expected RSV bronchiolitis surges.

Application of an egocentric social network approach to examine changes in social connections following treatment for anxiety and depression: A novel measurement tool for clinical trials research?

The epidemic of loneliness and social isolation has been recognized as a public health crisis warranting the same prioritization as other public health issues today, such as obesity, substance use disorders, and tobacco use. Social disconnection is particularly prevalent and disabling among individuals with anxiety and depression, yet it is inadequately evaluated and addressed in most clinical psychology treatment research. Studies generally employ global measures of perceived connectedness, loneliness, or relationship satisfaction, limiting understanding about elements of one's social network that may change with treatment. This study examined changes in the degree (number of people nominated) and quality of one's social network from pre-to post-treatment using an egocentric social network approach in 59 adults (mean age = 30.8 years, range = 18 to 54) with clinically elevated anxiety or depression who were randomized to a cognitive and behavioral positive valence treatment versus waitlist. Participants (egos) named people in their lives (alters) with whom they discussed important issues or spent free time. For each alter, participants rated how close they felt, how close they thought the alter felt to them, and how frequently they communicated. Linear regressions, which included treatment group as a predictor, revealed no group differences in changes in network degree, perceived alter feelings of closeness, or communication frequency, despite prior findings from this sample indicating larger increases in perceived global connectedness in the treatment group. Unexpectedly, the control group reported a greater increase in perceived closeness to alters. Post-hoc analyses revealed this was explained by the treatment group identifying more distal social ties (e.g., extended family, colleagues, roommates) as alters following treatment - an outcome positively associated with global improvements in connectedness. This proof-of-concept study suggests egocentric social network surveys may provide unique information on treatment-related changes in social functioning. Suggestions are provided for adaptations to facilitate application of social network surveys to mental health treatment research.

A core of cell wall proteins functions in wall integrity responses in Arabidopsis thaliana.

Cell walls surround all plant cells, and their composition and structure are tightly regulated to maintain cellular and organismal homeostasis. In response to wall damage, the cell wall integrity (CWI) system is engaged to ameliorate effects on plant growth. Despite the central role CWI plays in plant development, our current understanding of how this system functions at the molecular level is limited. Here, we investigated the transcriptomes of etiolated seedlings of mutants of Arabidopsis thaliana with defects in three major wall polysaccharides, pectin (quasimodo2), cellulose (cellulose synthase3 je5), and xyloglucan (xyloglucan xylosyltransferase1 and 2), to probe whether changes in the expression of cell wall-related genes occur and are similar or different when specific wall components are reduced or missing. Many changes occurred in the transcriptomes of pectin- and cellulose-deficient plants, but fewer changes occurred in the transcriptomes of xyloglucan-deficient plants. We hypothesize that this might be because pectins interact with other wall components and/or integrity sensors, whereas cellulose forms a major load-bearing component of the wall; defects in either appear to trigger the expression of structural proteins to maintain wall cohesion in the absence of a major polysaccharide. This core set of genes functioning in CWI in plants represents an attractive target for future genetic engineering of robust and resilient cell walls.

Young guard cells function dynamically despite low mechanical anisotropy but gain efficiency during stomatal maturation in Arabidopsis thaliana.

Stomata are pores at the leaf surface that enable gas exchange and transpiration. The signaling pathways that regulate the differentiation of stomatal guard cells and the mechanisms of stomatal pore formation have been characterized in Arabidopsis thaliana. However, the process by which stomatal complexes develop after pore formation into fully mature complexes is poorly understood. We tracked the morphogenesis of young stomatal complexes over time to establish characteristic geometric milestones along the path of stomatal maturation. Using 3D-nanoindentation coupled with finite element modeling of young and mature stomata, we found that despite having thicker cell walls than young guard cells, mature guard cells are more energy efficient with respect to stomatal opening, potentially attributable to the increased mechanical anisotropy of their cell walls and smaller changes in turgor pressure between the closed and open states. Comparing geometric changes in young and mature guard cells of wild-type and cellulose-deficient plants revealed that although cellulose is required for normal stomatal maturation, mechanical anisotropy appears to be achieved by the collective influence of cellulose and additional wall components. Together, these data elucidate the dynamic geometric and biomechanical mechanisms underlying the development process of stomatal maturation.

The viscoelasticity of high concentration monoclonal antibodies using particle tracking microrheology.

The viscoelasticity of monoclonal antibodies (mAbs) is important during their production, formulation, and drug delivery. High concentration mAbs can provide higher efficacy therapeutics (e.g., during immunotherapy) and improved efficiency during their production (economy of scale during processing). Two humanized mAbs were studied (mAb-1 and mAb-2) with differing isoelectric points. Using high speed particle tracking microrheology, we demonstrated that the mAb solutions have significant viscoelasticities above concentrations of 40 mg/ml. Power law viscoelasticity was observed over the range of time scales (10-4-1 s) probed for the high concentration mAb suspensions. The terminal viscosity demonstrated an exponential dependence on mAb concentration (a modified Mooney relationship) as expected for charged stabilized Brownian colloids. Gelation of the mAbs was explored by lowering the pH of the buffer and a power law scaling of the gelation transition was observed, i.e., the exponent of the anomalous diffusion of the probe particles scaled inversely with the gelation time.

Single-molecule tracking reveals dual front door/back door inhibition of Cel7A cellulase by its product cellobiose.

Degrading cellulose is a key step in the processing of lignocellulosic biomass into bioethanol. Cellobiose, the disaccharide product of cellulose degradation, has been shown to inhibit cellulase activity, but the mechanisms underlying product inhibition are not clear. We combined single-molecule imaging and biochemical investigations with the goal of revealing the mechanism by which cellobiose inhibits the activity of Trichoderma reesei Cel7A, a well-characterized exo-cellulase. We find that cellobiose slows the processive velocity of Cel7A and shortens the distance moved per encounter; effects that can be explained by cellobiose binding to the product release site of the enzyme. Cellobiose also strongly inhibits the binding of Cel7A to immobilized cellulose, with a Ki of 2.1 mM. The isolated catalytic domain (CD) of Cel7A was also inhibited to a similar degree by cellobiose, and binding of an isolated carbohydrate-binding module to cellulose was not inhibited by cellobiose, suggesting that cellobiose acts on the CD alone. Finally, cellopentaose inhibited Cel7A binding at micromolar concentrations without affecting the enzyme's velocity of movement along cellulose. Together, these results suggest that cellobiose inhibits Cel7A activity both by binding to the "back door" product release site to slow activity and to the "front door" substrate-binding tunnel to inhibit interaction with cellulose. These findings point to strategies for engineering cellulases to reduce product inhibition and enhance cellulose degradation, supporting the growth of a sustainable bioeconomy.

Trends in RSV testing patterns among infants presenting with bronchiolitis: Results from four United States health systems, 2015-2023.

BACKGROUND: Bronchiolitis due to respiratory syncytial virus (RSV) is the leading cause of hospitalization among American infants. The overall burden of RSV among infants has been historically under-estimated due to variable testing practices, particularly in the outpatient setting. Universal masking and social distancing implemented during the coronavirus disease 2019 (COVID-19) pandemic altered RSV seasonality, however potential consequences on RSV testing practices across different healthcare settings and sociodemographic groups have not been described. Variable testing practices could also affect accurate assessment of the effects of two recently approved RSV preventative agents targeting infants. METHODS: Utilizing real-time clinical and viral surveillance, we examined RSV testing practices among infants with bronchiolitis within four United States healthcare systems across different healthcare settings and sociodemographic groups pre- and post-COVID-19. RESULTS: RSV testing among infants with bronchiolitis increased since 2015 within each healthcare system across all healthcare settings and sociodemographic groups, with a more dramatic increase since the COVID-19 pandemic. Outpatient testing remained disproportionately low compared to hospital-based testing, although there were no major differences in testing frequency among sociodemographic groups in either setting. CONCLUSIONS: Although RSV testing increased among infants with bronchiolitis, relatively low outpatient testing rates remain a key barrier to accurate RSV surveillance.

Nucleocytoplasmic transport rates are regulated by cellular processes that modulate GTP availability.

Nucleocytoplasmic transport (NCT), the facilitated diffusion of cargo molecules between the nucleus and cytoplasm through nuclear pore complexes (NPCs), enables numerous fundamental eukaryotic cellular processes. Ran GTPase uses cellular energy in the direct form of GTP to create a gradient across the nuclear envelope (NE) that drives the majority of NCT. We report here that changes in GTP availability resulting from altered cellular physiology modulate the rate of NCT, as monitored using synthetic and natural cargo, and the dynamics of Ran itself. Cell migration, cell spreading, and/or modulation of the cytoskeleton or its connection to the nucleus alter GTP availability and thus rates of NCT, regulating RNA export and protein synthesis. These findings support a model in which changes in cellular physiology that alter GTP availability can regulate the rate of NCT, impacting fundamental cellular processes that extensively utilize NCT.

Tissue oxygen saturation is positively correlated with oxygen delivery and cardiac output in a canine hemorrhagic shock and resuscitation model.

OBJECTIVE: To determine if tissue oxygen saturation (StO2) correlates with oxygen delivery (DO2) and/or cardiac output (CO) in a canine hemorrhagic shock model. ANIMALS: 8 healthy purpose-bred dogs. METHODS: Dogs were anesthetized, and hemorrhagic shock was induced by withdrawing up to 60% of total blood volume, targeting a mean arterial pressure (MAP) of 40 mm Hg. The withdrawn blood was returned to the patient in 2 equal aliquots. Data was collected at 4 time points: 10 minutes after MAP was stabilized under anesthesia (time point [TP]-1), 10 minutes after up to 60% of blood volume was removed to target a MAP of 40 mm Hg (TP2), 10 minutes after the return of 50% of shed blood (TP3), and 10 minutes after the return of the remaining 50% of shed blood (TP4). Total blood volume withdrawn, StO2, CO, heart rate, and MAP were recorded, and DO2 was calculated at each TP. RESULTS: Mean StO2 significantly decreased between TP1 (77.8% [± 9.54]) and TP2 (44.8% [± 19.5]; P < .001 vs TP1). Mean StO2 increased to 63.1% (± 9.85) at TP3, but remained significantly lower compared to TP1 (P = .002). There was no difference between mean StO2 at TP4 (82.5% [± 12.6]) versus TP1 (P = .466). StO2 has a strong, positive correlation to both CO (r = 0.80; P < .001) and DO2 (r = 0.75; P < .001). CLINICAL RELEVANCE: A decrease in StO2 may be used in conjunction with physical examination findings and diagnostic parameters to support a diagnosis of shock. The return of shed blood was correlated with increases in StO2, DO2, and CO, suggesting that StO2 may be used as a marker of adequate resuscitation.