Occupancy of the HbYX hydrophobic pocket is sufficient to induce gate opening in the archaeal 20S proteasomes.

Enhancing proteasome function has been a long-standing but challenging target of interest for the potential treatment of neurodegenerative diseases, emphasizing the importance of understanding proteasome activation mechanisms. Most proteasome activator complexes use the C-terminal HbYX motif to bind and trigger gate-opening in the 20S proteasome. This study defines a critical molecular interaction in the HbYX mechanism that triggers gate opening. Here, we focus on the Hb site interaction and find it plays a surprisingly central and crucial role in driving the allosteric conformational changes that induce gate opening in the archaeal 20S. We examined the cryo-EM structure of two mutant archaeal proteasomes, αV24Y T20S and αV24F T20S. These two mutants were engineered to place a bulky aromatic residue in the HbYX hydrophobic pocket and both mutants are highly active, though their mechanisms of activation are undefined. Collectively, our findings indicate that the interaction between the Hb group of the HbYX motif and its corresponding hydrophobic pocket is sufficient to induce gate opening in a mechanistically similar way to the HbYX motif. The involved activation mechanism appears to involve expansion of this hydrophobic binding site affecting the state of the IT switch to triggering gate-opening. Furthermore, we show that the canonical αK66 residue, understood to be critical for proteasome activator binding, plays a key role in stabilizing the open gate, irrespective of activator binding. This study differentiates between the residues in the HbYX motif that support binding interactions ("YX") versus those that allosterically contribute to gate opening (Hb). The insights reported here will guide future drug development efforts, particularly in designing small molecule proteasome activators, by targeting the identified hydrophobic pocket.

A Retrospective Cohort Analysis of Analgosedation Requirements in COVID-19 Compared to Non-COVID-19 Extracorporeal Membrane Oxygenation Patients.

BACKGROUND: Reports have described increased sedation requirements in patients with acute respiratory distress syndrome (ARDS) while on extracorporeal membrane oxygenation (ECMO) and for intubated COVID-19 patients. Thus, the objective of this study was to assess the analgosedation requirements of COVID-19 patients receiving ECMO compared to non-COVID-19 ECMO patients. METHODS: This retrospective, observational cohort study included adult patients with ARDS requiring venovenous or venopulmonary arterial ECMO admitted to a single intensive care unit from January 2017 to December 2021. Patients were categorized as COVID-19 ECMO or non-COVID-19 ECMO. The primary outcome was median daily dosing of parenteral analgosedative medications. Pertinent secondary outcomes included incidence of extubation or tracheostomy and change in sedation following tracheostomy or addition of oral agents. RESULTS: A total of 109 patients were evaluated; 63 COVID-19 ECMO patients and 46 non-COVID ECMO patients. The primary outcome was statistically higher in the COVID-19 compared to non-COVID-19 patients for propofol (4131.0 mg vs 2704.8 mg, P < .001), dexmedetomidine (1581.4 mcg vs 1081.3 mcg, P = .016), and parenteral morphine equivalents ([PME], 209.3 mg vs 154.1 mg, P = .027), but only propofol remained significant after adjustment for weight (31.1 mcg/kg/day vs 37.7 mcg/kg/day, P = .014). COVID-19 was significantly associated with increased propofol and PME requirements after adjustment for confounders on linear regression analysis. COVID-19 patients had more days with non-zero dose for propofol (8 days vs 7 days), dexmedetomidine (13 days vs 8.5 days), and PME (17 days vs 8.5 days). The only interventions that were associated with reductions in propofol dose were tracheostomy and antipsychotics. CONCLUSIONS: COVID-19 patients on ECMO had significantly longer durations and higher doses of propofol, dexmedetomidine, and parenteral opioids over the first 28 days of cannulation. The only interventions that were associated with statistical reductions in propofol were antipsychotics and tracheostomy.

Comparison of Outcomes in Patients Requiring Mechanical Circulatory Support Who Received Cangrelor in Addition to Anticoagulation Versus Anticoagulation Alone.

OBJECTIVES: To evaluate the safety of cangrelor administered concurrently with heparin or bivalirudin in patients on mechanical circulatory support. DESIGN: A single-center, retrospective cohort study of adult patients consecutively admitted between January 2016 and October 2020. SETTING: A tertiary medical center. PARTICIPANTS: Adult patients admitted to the cardiovascular intensive care unit put on mechanical circulatory support for acute myocardial infarction (AMI) or non-AMI indications. Patients who received cangrelor underwent percutaneous coronary intervention with stenting during the index event or within the last year. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the incidence of major bleeding, defined by the Extracorporeal Life Support Organization criteria, in patients with mechanical circulatory support receiving cangrelor plus anticoagulation with heparin or bivalirudin with or without aspirin versus patients who did not receive cangrelor. Sixty-eight patients were included in the study. Twenty-nine patients received cangrelor, and 39 did not. Cangrelor was not associated with an increase in major bleeding; however, the CI was wide (adjusted hazard ratio 1.93, 95% CI 0.61-6.11; p = 0.262). CONCLUSIONS: Patients receiving cangrelor did not appear to be at higher risk of major bleeding compared to patients not receiving cangrelor. Larger trials should be conducted to better evaluate the safety of cangrelor in patients with mechanical circulatory support.

Individual Quality Drives Life History Variation in a Long-Lived Marine Predator.

AbstractIndividual quality and environmental conditions may mask or interact with energetic trade-offs in life history evolution. Deconstructing these sources of variation is especially difficult in long-lived species that are rarely observed on timescales long enough to disentangle these effects. Here, we investigated relative support for variation in female quality and costs of reproduction as factors shaping differences in life history trajectories using a 32-year dataset of repeated reproductive measurements from 273 marked, known-age female gray seals (Halichoerus grypus). We defined individual reproductive investment using two traits, reproductive frequency (a female's probability of breeding) and provisioning performance (offspring weaning mass). Fitted hierarchical Bayesian models identified individual investment relative to conspecifics (over a female's entire life and in three age classes) and subsequently estimated how these investment metrics and the Atlantic Multidecadal Oscillation are associated with longevity. Individual differences (i.e., quality) contributed a large portion of the variance in reproductive traits. Females that consistently invest well in their offspring relative to other females survive longer. The best-supported model estimated survival as a function of age class-specific provisioning performance, where late-life performance was particularly variable and had the greatest impact on survival, possibly indicating individual variation in senescence. There was no evidence to support a trade-off in reproductive performance and survival at the individual level. Overall, these results suggest that in gray seals, individual quality is a stronger driver in life history variation than individual strategies resulting from energetic trade-offs.

High resolution structures define divergent and convergent mechanisms of archaeal proteasome activation.

Considering the link between neurodegenerative diseases and impaired proteasome function, and the neuro-protective impact of enhanced proteasome activity in animal models, it's crucial to understand proteasome activation mechanisms. A hydrophobic-tyrosine-any residue (HbYX) motif on the C-termini of proteasome-activating complexes independently triggers gate-opening of the 20S core particle for protein degradation; however, the causal allosteric mechanism remains unclear. Our study employs a structurally irreducible dipeptide HbYX mimetic to investigate the allosteric mechanism of gate-opening in the archaeal proteasome. High-resolution cryo-EM structures pinpoint vital residues and conformational changes in the proteasome α-subunit implicated in HbYX-dependent activation. Using point mutations, we simulated the HbYX-bound state, providing support for our mechanistic model. We discerned four main mechanistic elements triggering gate-opening: 1) back-loop rearrangement adjacent to K66, 2) intra- and inter- α subunit conformational changes, 3) occupancy of the hydrophobic pocket, and 4) a highly conserved isoleucine-threonine pair in the 20S channel stabilizing the open and closed states, termed the "IT switch." Comparison of different complexes unveiled convergent and divergent mechanism of 20S gate-opening among HbYX-dependent and independent activators. This study delivers a detailed molecular model for HbYX-dependent 20S gate-opening, enabling the development of small molecule proteasome activators that hold promise to treat neurodegenerative diseases.

Minimal mechanistic component of HbYX-dependent proteasome activation that reverses impairment by neurodegenerative-associated oligomers.

The implication of reduced proteasomal function in neurodegenerative diseases combined with studies showing the protective effects of increasing proteasome activity in animal models highlight the need to understand the capacity for proteasome activation by small molecules. The C-terminal HbYX motif is present on many proteasome binding proteins and functions to tether activators to the 20S core particle. Previous studies have shown that peptides with a HbYX motif can autonomously activate 20S gate-opening to allow protein degradation. In this study, through an iterative process of peptide synthesis, we design a HbYX-like dipeptide mimetic that represents only the fundamental components of the HbYX motif. The mimetic robustly induces gate-opening in archaeal, yeast, and mammalian proteasomes. We identify multiple proteasome α subunit residues in the archaeal proteasome involved in HbYX-dependent activation. When stimulated by the mimetic, the mammalian 20S can degrade unfolded proteins such as tau. Findings using our peptide mimetic suggest the HbYX-dependent mechanism requires cooperative binding in at least two intersubunit pockets of the α ring. Most significantly, our peptide mimetic reverses proteasome impairment by neurodegenerative disease-associated oligomers. Collectively, these results validate HbYX-like molecules as having robust potential to stimulate proteasome function, which are potentially useful for treating neurodegenerative diseases.

Large offspring have enhanced lifetime reproductive success: Long-term carry-over effects of weaning size in gray seals (Halichoerus grypus).

An individual's size in early stages of life may be an important source of individual variation in lifetime reproductive performance, as size effects on ontogenetic development can have cascading physiological and behavioral consequences throughout life. Here, we explored how size-at-young influences subsequent reproductive performance in gray seals (Halichoerus grypus) using repeated encounter and reproductive data on a marked sample of 363 females that were measured for length after weaning, at ~4 weeks of age, and eventually recruited to the Sable Island breeding colony. Two reproductive traits were considered: provisioning performance (mass of weaned offspring), modeled using linear mixed effects models; and reproductive frequency (rate at which a female returns to breed), modeled using mixed effects multistate mark-recapture models. Mothers with the longest weaning lengths produced pups 8 kg heavier and were 20% more likely to breed in a given year than mothers with the shortest lengths. Correlation in body lengths between weaning and adult life stages, however, is weak: Longer pups do not grow to be longer than average adults. Thus, covariation between weaning length and future reproductive performance appears to be a carry-over effect, where the size advantages afforded in early juvenile stages may allow enhanced long-term performance in adulthood.

Minimal mechanistic component of HbYX-dependent proteasome activation.

The implication of reduced proteasomal function in neurodegenerative diseases combined with numerous studies showing the protective effects of increasing proteasome activity in animal models justify the need to understand how the proteasome is activated for protein degradation. The C-terminal HbYX motif is present on many proteasome binding proteins and functions to tether activators to the 20S core particle. Peptides with a HbYX motif can also autonomously activate 20S gate-opening to allow protein degradation, but the underlying allosteric molecular mechanism is not clear. We designed a HbYX-like dipeptide mimetic that represents only the fundamental components of the HbYX motif to allow rigorous elucidation of the underlying molecular mechanisms of HbYX induced 20S gate-opening in the archaeal and mamalian proteasome. By generating several high-resolution cryo-EM structures (e.g. 1.9Å) we identified multiple proteasome α subunit residues involved in HbYX-dependent activation and the conformational changes involved in gate-opening. In addition, we generated mutants probing these structural findings and identified specific point mutations that strongly activate the proteasome by partially mimicking a HbYX-bound state. These structures resolve 3 novel mechanistic features that are critical for allosteric α subunit conformational changes that ultimately trigger gate-opening: 1) rearrangement of the loop adjacent to K66, 2) inter- and intra- α subunit conformational changes and 3) a pair of IT residues on the α N-terminus in the 20S channel that alternate binding sites to stabilize the open and closed states. All gate-opening mechanisms appear to converge on this "IT switch". When stimulated by the mimetic, the human 20S can degrade unfolded proteins such as tau, and prevent proteasomal inhibition by toxic soluble oligomers. Collectively, the results presented here provide a mechanistic model of HbYX-dependent 20S gate-opening and offer proof of concept for the robust potential of HbYX-like small molecules to stimulate proteasome function, which could be useful to treat neurodegenerative diseases.

Isolation and Identification of Acylphloroglucinols in the Medicinal Plant, Melaleuca alternifolia (Australian Tea Tree).

Melaleuca alternifolia (tea tree), family Myrtaceae, is endemic to the northern rivers of NSW, Australia. Since 1925, the volatile components of the hydro- and steam-distilled oils of the leaves have been studied in detail. However, the less-volatile compounds have not been investigated. Using an ethanolic extract of the seedling leaves, the non-volatile components were studied using gas chromatography-mass spectrometry (GC/MS) and liquid chromatography- mass spectrometry (LC/MS). Four of these less-volatile components were isolated by preparative-HPLC from young seedling leaves and identified as the acylphloroglucinols 1-(2,6-dihydroxy-4-methoxy-3-methylphenyl)-2-methylpropan-1-one, callisalignone A, 1-(2,6-dihydroxy-4-methoxyphenyl)-3-methylbutan-1-one and pulverulentone B described here for the first time from M. alternifolia. These compounds change in concentration in the leaf sets as later seedling leaves mature on the seedling.

Heparin Monitoring with an Anti-Xa Protocol Compared to Activated Clotting Time in Patients on Temporary Mechanical Circulatory Support.

BACKGROUND: Temporary mechanical circulatory support (tMCS) devices are used for patients with severe cardiac or respiratory failure; however, these patients are at high risk for clotting and bleeding. The best method to monitor heparin in these patients has not been established. OBJECTIVE: To determine the risks for bleeding and clotting while monitoring heparin with either anti-Xa or activated clotting time (ACT) in tMCS patients. METHODS: A retrospective cohort study was conducted on tMCS patients who received heparin adjusted according to an anti-Xa or ACT protocol. The primary outcome was incidence of major bleeding. Pertinent secondary outcomes were individual components of the primary outcome, clotting events, and time to therapeutic range. RESULTS: There were 103 patients included in the study: 53 in the ACT group and 50 in the anti-Xa group. Overall, there were 30 (56.6%) patients with major bleeding in the ACT group, compared with 16 (32%) patients in the anti-Xa group (P = 0.017). An anti-Xa-based protocol was associated with a decreased hazard of major bleeding (hazard ratio = 0.388 [0.215-0.701]; P = 0.002) in the univariate analysis. In the multivariable analysis, an anti-Xa protocol remained associated with a significantly lower hazard of bleeding. Findings were similar when broken down into more discrete subgroups of the entire cohort, extracorporeal membrane oxygenation life support (ECMO), and non-ECMO groups. CONCLUSION AND RELEVANCE: Anti-Xa monitoring was associated with a lower hazard of bleeding during tMCS compared to an ACT-based protocol. Further studies should evaluate if anti-Xa monitoring should be preferentially used in tMCS.

Validation of a Novel Multitarget Blood Test Shows High Sensitivity to Detect Early Stage Hepatocellular Carcinoma.

BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide. Although biannual ultrasound surveillance with or without α-fetoprotein (AFP) testing is recommended for at-risk patients, sensitivity for early stage HCC, for which potentially curative treatments exist, is suboptimal. We conducted studies to establish the multitarget HCC blood test (mt-HBT) algorithm and cut-off values and to validate test performance in patients with chronic liver disease. METHODS: Algorithm development and clinical validation studies were conducted with participants in an international, multicenter, case-control study. Study subjects had underlying cirrhosis or chronic hepatitis B virus; HCC cases were diagnosed per the American Association for the Study of Liver Diseases criteria and controls were matched for age and liver disease etiology. Whole blood and serum were shipped to a central laboratory and processed while blinded to case/control status. An algorithm was developed for the mt-HBT, which incorporates methylation biomarkers (HOXA1, TSPYL5, and B3GALT6), AFP, and sex. RESULTS: In algorithm development, with 136 HCC cases (60% early stage) and 404 controls, the mt-HBT showed 72% sensitivity for early stage HCC at 88% specificity. Test performance was validated in an independent cohort of 156 HCC cases (50% early stage) and 245 controls, showing 88% overall sensitivity, 82% early stage sensitivity, and 87% specificity. Early stage sensitivity in clinical validation was significantly higher than AFP at 20 ng/mL or greater (40%; P < .0001) and GALAD (gender, age, Lens culinaris agglutinin-reactive AFP, AFP, and des-γ-carboxy-prothrombin score) of -0.63 or greater (71%; P = .03), although AFP and GALAD at these cut-off values had higher specificities (100% and 93%, respectively). CONCLUSIONS: The mt-HBT may significantly improve early stage HCC detection for patients undergoing HCC surveillance, a critical step to increasing curative treatment opportunities and reducing mortality. ClinicalTrials.gov number NCT03628651.

Analytical validation of a novel multi-target blood-based test to detect hepatocellular carcinoma.

INTRODUCTION: Surveillance is essential to diagnose and more effectively treat hepatocellular carcinoma (HCC) in at-risk patients. However, the performance of currently recommended surveillance strategies is suboptimal, particularly for early-stage detection, and patient adherence remains low. Here, we establish the analytical performance of a novel liquid biopsy test to evaluate the presence of HCC. METHODS: The multi-target HCC blood test (mt-HBT) integrates results from three DNA methylation markers (HOXA1, TSPYL5, and B3GALT6), the protein biomarker α-fetoprotein (AFP), and patient sex. The methylation markers are quantified from cell-free DNA extracted from plasma, and AFP is measured from serum. We conducted analytical validation studies on the mt-HBT, including analytical sensitivity, linearity, cross-contamination, interference, analytical accuracy, and precision. RESULTS: The mt-HBT performance met all pre-specified analytical performance criteria. The test demonstrated high reproducibility, with ≥97% concordance relative to the expected results for six categories of surrogate samples across the test's dynamic range. Of 17 candidate interfering substances, none caused significant interference to biomarker quantitation, and no occurrences of sample-to-sample cross-contamination were observed. CONCLUSION: These data demonstrate that the mt-HBT can produce consistent, reliable results for patients in the intended-use population, for whom surveillance is recommended.

As Time Goes by: Understanding Child and Family Factors Shaping Behavioral Outcomes After Traumatic Brain Injury.

Objective: To model pre-injury child and family factors associated with the trajectory of internalizing and externalizing behavior problems across the first 3 years in children with pediatric traumatic brain injury (TBI) relative to children with orthopedic injuries (OI). Parent-reported emotional symptoms and conduct problems were expected to have unique and shared predictors. We hypothesized that TBI, female sex, greater pre-injury executive dysfunction, adjustment problems, lower income, and family dysfunction would be associated with less favorable outcomes. Methods: In a prospective longitudinal cohort study, we examined the level of behavior problems at 12 months after injury and rate of change from pre-injury to 12 months and from 12 to 36 months in children ages 4-15 years with mild to severe TBI relative to children with OI. A structural equation model framework incorporated injury characteristics, child demographic variables, as well as pre-injury child reserve and family attributes. Internalizing and externalizing behavior problems were indexed using the parent-rated Emotional Symptoms and Conduct Problems scales from the Strengths and Difficulties questionnaire. Results: The analysis cohort of 534 children [64% boys, M (SD) 8.8 (4.3) years of age] included 395 with mild to severe TBI and 139 with OI. Behavior ratings were higher after TBI than OI but did not differ by TBI severity. TBI, higher pre-injury executive dysfunction, and lower income predicted the level and trajectory of both Emotional Symptoms and Conduct Problems at 12 months. Female sex and poorer family functioning were vulnerability factors associated with greater increase and change in Emotional Symptoms by 12 months after injury; unique predictors of Conduct Problems included younger age and prior emotional/behavioral problems. Across the long-term follow-up from 12 to 36 months, Emotional Symptoms increased significantly and Conduct Problems stabilized. TBI was not a significant predictor of change during the chronic stage of recovery. Conclusions: After TBI, Emotional Symptoms and Conduct Problem scores were elevated, had different trajectories of change, increased or stayed elevated from 12 to 36 months after TBI, and did not return to pre-injury levels across the 3 year follow-up. These findings highlight the importance of addressing behavioral problems after TBI across an extended time frame.

Post-Concussion and Post-Traumatic Stress Symptoms after Pediatric Traumatic Brain Injury: Shared Vulnerability Factors?

Following pediatric traumatic brain injury (TBI), post-concussion symptoms (PCS) and post-traumatic stress symptoms (PTSS) occur commonly; however, it is unknown to what degree they overlap. The study examined PCS and PTSS persisting 7 weeks after injury in children and adolescents ages 8-15 years with TBI (n = 89) or extracranial injury (EI; n = 40) after vehicle collisions. TBI was divided into mild, complicated-mild/moderate, and severe groups. Parents retrospectively rated children's pre-injury symptoms and behavior problems, and children completed self-report measures after injury. PCS and PTSS total scores were significantly correlated in TBI and EI groups, respectively, for child (rs = 0.75; rs = 0.44), and adolescent (rs = 0.61; rs = 0.67) cohorts. Generalized linear models examined whether injury type and severity, age, sex, and pre-injury symptom ratings predicted PCS and PTSS total scores and factor scores. Specific PCS and PTSS factor scores were elevated in different TBI severity groups, with most frequent problems following mild or severe TBI. PCS did not differ by age; however, girls had more emotional symptoms than boys. Only PTSS were predicted by pre-injury externalizing behavior. Significant age by sex interactions indicated that adolescent girls had more total, avoidance, and hyperarousal PTSS symptoms than younger girls or all boys. PCS and PTSS significantly overlapped in both TBI and EI groups, highlighting shared persistent symptoms after injury. Shared vulnerability factors included female sex, milder TBI, and poorer pre-injury adjustment. Older age was a unique vulnerability factor for PTSS. Psychological health interventions after injury should be customized to address comorbid symptoms.

A Novel Blood-Based Panel of Methylated DNA and Protein Markers for Detection of Early-Stage Hepatocellular Carcinoma.

BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) can be treated effectively if detected at an early stage. Recommended surveillance strategies for at-risk patients include ultrasound with or without α-fetoprotein (AFP), but their sensitivity is suboptimal. We sought to develop a novel, blood-based biomarker panel with improved sensitivity for early-stage HCC detection. METHODS: In a multicenter, case-control study, we collected blood specimens from patients with HCC and age-matched controls with underlying liver disease but without HCC. Ten previously reported methylated DNA markers (MDMs) associated with HCC, methylated B3GALT6 (reference DNA marker), and 3 candidate proteins, including AFP, were assayed and analyzed by a logistic regression algorithm to predict HCC cases. The accuracy of the multi-target HCC panel was compared with that of other blood-based biomarkers for HCC detection. RESULTS: The study included 135 HCC cases and 302 controls. We identified a multi-target HCC panel of 3 MDMs (HOXA1, EMX1, and TSPYL5), B3GALT6 and 2 protein markers (AFP and AFP-L3) with a higher sensitivity (71%, 95% CI: 60-81%) at 90% specificity for early-stage HCC than the GALAD score (41%, 95% CI: 30-53%) or AFP ≥7.32 ng/mL (45%, 95% CI: 33-57%). The AUC for the multi-target HCC panel for detecting any stage HCC was 0.92 compared with 0.87 for the GALAD score and 0.81 for AFP alone. The panel performed equally well in important subgroups based on liver disease etiology, presence of cirrhosis, or sex. CONCLUSIONS: We developed a novel, blood-based biomarker panel that demonstrates high sensitivity for early-stage HCC. These data support the potential for liquid biopsy detection of early-stage HCC to clinically benefit at-risk patients. This study was registered on ClinicalTrials.gov (NCT03628651).

Variation in individual reproductive performance amplified with population size in a long-lived carnivore.

Individual variation in reproductive ability is a key component of natural selection within populations, driving the evolution of life histories and population responses to changing environmental conditions. Evidence that population density affects individual-level fitness in wild populations is limited, particularly for long-lived animals, which are difficult to observe on a biologically relevant scale. We tested for individual heterogeneity in reproductive performance in female grey seals (Halichoerus grypus) using 35 yr of mark-resighting data at Sable Island, Canada (43.93° N 59.91° W). We used Bayesian generalized linear mixed-effect models and multistate open robust design mark-resight models to investigate whether population size negatively influences individual reproductive performance. We measured reproductive performance in two ways: reproductive frequency (the probability of returning to the island to breed) and annual provisioning performance (the probability of successfully weaning a pup given a female bred). Sighting histories of 1,655 known-aged females with a total of 22,961 pupping events were used for analysis. After accounting for effects of female age, parity, and random year effects, we found that both provisioning performance and reproductive frequency demonstrated a strong, positive correlation with population size. Among-individual variance in reproductive traits and responses to population size indicated considerable heterogeneity in overall reproductive performance. As population size grew, "robust" females increased their reproductive performance more than their more "frail" conspecifics in both reproductive traits, resulting in an amplification of differences among individuals. Consequently, simulations from posterior distributions revealed a large fitness consequence of heterogeneity in this population, with "frail" individuals having 47.1% fewer successful pups than more "robust" females (mean reproductive output ± SD: 9.12 ± 3.77 pups for frail individuals, 16.97 ± 2.94 for robust individuals). Repeatability of overall reproductive performance across environments indicates individual quality may be more influential to lifetime reproductive success than costs associated with reproductive investment. This quantification of relative fitness and its dynamics is crucial to understanding broad evolutionary processes in natural populations.

Adequacy of hemostatic resuscitation improves therapeutic efficacy of recombinant activated factor VII and reduces reexploration rate for bleeding in postoperative cardiac surgery patients with refractory hemorrhage.

Background: Excessive bleeding and surgical reexploration are common complications that increase the risk of multi-organ failure and prolonged hospitalization after cardiac surgery. Off-label use of recombinant activated factor VII (rFVIIa) is a recommended treatment for refractory bleeding. Objective: The objective of the study is to determine if the adequacy of hemostatic resuscitation enhances the efficacy of rFVIIa. Methods: This retrospective, observational, cohort study included patients who received rFVIIa for refractory postoperative bleeding after cardiac surgery. Patients were divided into two groups based on the presence or absence of adequate coagulation resuscitation before rFVIIa administration, defined as international ratio (INR) ≤1.5, platelet count ≥100 K/mL, and fibrinogen ≥200 mg/dL. The failure of rFVIIa treatment was defined as surgical reexploration within 24 h, thoracostomy drainage >400 mL/h within 6 h or transfusion of additional blood products or another rFVIIa dose within 6 h after initial rFVIIa dose. Results: Of the 3833 patients, screened who underwent cardiothoracic surgery procedures, 58 patients received rFVIIa for refractory postoperative bleeding. Successful hemostasis with rFVIIa was more likely in patients who were adequately resuscitated compared with those who were not (20 [71.4%] vs. 10 [33.3%], respectively; P = 0.0046). Multiple logistic regression analysis indicated that patients who were adequately resuscitated before rFVIIa were less likely to fail treatment (odds ratio, 0.16; 95% confidence interval [0.04-0.62]; P = 0.007). Conclusions: The therapeutic efficacy of rFVIIa is dependent on the adequacy of hemostatic resuscitation; restoration of normal serum fibrinogen, INR, and platelet counts >100 K/mL may provide an adequate substrate for rFVIIa to be effective in managing refractory postoperative cardiac surgical bleeding.

The effect of the Preparing Pequeños small-group cognitive instruction program on academic and concurrent social and behavioral outcomes in young Spanish-speaking dual-language learners.

Academic achievement for young dual language learners (DLL) is a critically acknowledged problem of national significance that has been understudied. To address this shortage, this study evaluated the effectiveness of Preparing Pequeños, an integrated small-group instruction program designed to promote increased learning for Spanish speaking DLL in language, literacy, and math. The DLL in the randomized Preparing Pequeños intervention classrooms were compared to control DLL with comparable Spanish language delays and in which the school district's core curriculum was being implemented. Intervention teachers and paraprofessionals, as part of Preparing Pequeños, implemented new classroom and time management systems in order to conduct 90 min of small-group instruction four days each week across the school year. In total, 51 control and 52 intervention classrooms participated; pre-test measures were completed with 829 children, with 777 of these children also completing post-test measures (7% attrition). Results showed that intervention teachers and paraprofessionals, as compared to control, showed greater increases in most of the targeted areas of cognitive instruction (d range = 0.60-2.38) and in the use of small groups (d range = 3.32-4.46), progress monitoring (d = 0.17) to inform instruction, and team teaching (d = 1.94). Intervention children, as compared to control, showed significantly greater gains in Spanish oral language, print knowledge, phonological awareness, and phonics with small to large effect sizes (d range = 0.14-0.52). Also, potentially as a result of greater attention to children's individual needs and support for managing their behavior, intervention children, as compared to control, showed greater decreases in school avoidance, anger, and aggression with small effect sizes (d range = -0.22 to -0.29). Results are discussed in relation to the need for greater attention in teachers' training in effective approaches for small-group instruction.

Self-regulation and the Development of Literacy and Language Achievement from Preschool through Second Grade.

Previous research has established that higher levels of behavioral self-regulation are associated with higher levels of language and literacy. In this study, we take a more developmental perspective by considering how trajectories of self-regulation development (early, intermediate, late) predict the way literacy and language skills develop from preschool through second grade. Children (n = 351) were assessed twice per year for up to four years on indicators of decoding, reading comprehension, phonological awareness, and vocabulary. Using non-linear growth curve models, we found that children who demonstrated self-regulation earlier had higher language and literacy skills throughout preschool to second grade. More specifically, earlier self-regulation trajectories were associated with both higher levels and earlier development of both decoding and reading comprehension, but not faster development. Children with early self-regulation trajectories developed phonological awareness earlier than those with late self-regulation trajectories. Finally, children with early self-regulation trajectories had higher levels of vocabulary than children with intermediate trajectories, but did not differ on the rate or timing of vocabulary development. Findings point to the enduring and interconnected nature of self-regulation and children's language and literacy development.

Nurturing the preterm infant brain: leveraging neuroplasticity to improve neurobehavioral outcomes.

An intrinsic feature of the developing brain is high susceptibility to environmental influence-known as plasticity. Research indicates cascading disruption to neurological development following preterm (PT) birth; yet, the interactive effects of PT birth and plasticity remain unclear. It is possible that, with regard to neuropsychological outcomes in the PT population, plasticity is a double-edged sword. On one side, high plasticity of rapidly developing neural tissue makes the PT brain more vulnerable to injury resulting from events, including inflammation, hypoxia, and ischemia. On the other side, plasticity may be a mechanism through which positive experience can normalize neurological development for PT children. Much of the available literature on PT neurological development is clinically weighted and focused on diagnostic utility for predicting long-term outcomes. Although diagnostic utility is valuable, research establishing neuroprotective factors is equally beneficial. This review will: (1) detail specific mechanisms through which plasticity is adaptive or maladaptive depending on the experience; (2) integrate research from neuroimaging, intervention, and clinical science fields in a summary of findings suggesting inherent plasticity of the PT brain as a mechanism to improve child outcomes; and (3) summarize how responsive caregiving experiences situate parents as agents of change in normalizing PT infant brain development.