87 research outputs found

    Review of the Interactions between Catfishes and Freshwater Mollusks in North America

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    Catfishes are important in freshwater ecosystems not only as consumers, but also as essential partners in symbiotic relationships with other organisms. Freshwater mollusks are among the many organisms that have interactions with catfishes. For example, ictalurids are hosts for larvae of several native freshwater mussel species. The larvae, which attach briefly to gills or fins of fish to complete their development to the free-living juvenile stage, disperse via upstream and downstream movement of host fish. In turn, freshwater mussels serve as a food source for some catfish species while other catfish species may use spent mussel shells for habitat. Ictalurids also benefit from the conservation status of many freshwater mussel species. Federal and state laws protecting these invertebrates can preserve water quality and habitat and, at times, provide incentives and funding for conservation and restoration of stream and riparian habitats

    A Guide to Missouri\u27s Freshwater Mussels

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    https://bearworks.missouristate.edu/books/1017/thumbnail.jp

    Spatial and Temporal Trends of Freshwater Mussel Assemblages in the Meramec River Basin, Missouri, USA

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    The Meramec River basin in east-central Missouri has one of the most diverse unionoid mussel faunas in the central United States with .40 species identified. Data were analyzed from historical surveys to test whether diversity and abundance of mussels in the Meramec River basin (Big, Bourbeuse, and Meramec rivers, representing .400 river miles) decreased between 1978 and 1997. We found that over 20 y, species richness and diversity decreased significantly in the Bourbeuse and Meramec rivers but not in the Big River. Most species were found at fewer sites and in lower numbers in 1997 than in 1978. Federally endangered species and Missouri Species of Conservation Concern with the most severe temporal declines were Alasmidonta viridis, Arcidens confragosus, Elliptio crassidens, Epioblasma triquetra, Fusconaia ebena, Lampsilis abrupta, Lampsilis brittsi, and Simpsonaias ambigua. Averaged across all species, mussels were generally being extirpated from historical sampling sites more rapidly than colonization was occurring. An exception was one reach of the Meramec River between river miles 28.4 and 59.5, where mussel abundance and diversity were greater than in other reaches and where colonization of Margaritiferidae, Lampsilini, and Quadrulini exceeded extirpation. The exact reasons mussel diversity and abundance have remained robust in this 30-mile reach is uncertain, but the reach is associated with increased gradients, few long pools, and vertical rock faces, all of which are preferable for mussels. Complete loss of mussel communities at eight sites (16%) with relatively diverse historical assemblages was attributed to physical habitat changes including bank erosion, unstable substrate, and sedimentation. Mussel conservation efforts, including restoring and protecting riparian habitats, limiting the effects of in-stream sand and gravel mining, monitoring and controlling invasive species, and protecting water quality, may be warranted in the Meramec River basin

    Combined Norepinephrine/Serotonergic Reuptake Inhibition: Effects on Maternal Behavior, Aggression, and Oxytocin in the Rat

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    Background: Few systematic studies exist on the effects of chronic reuptake of monoamine neurotransmitter systems during pregnancy on the regulation of maternal behavior (MB), although many drugs act primarily through one or more of these systems. Previous studies examining fluoxetine and amfonelic acid treatment during gestation on subsequent MB in rodents indicated significant alterations in postpartum maternal care, aggression, and oxytocin levels. In this study, we extended our studies to include chronic gestational treatment with desipramine or amitriptyline to examine differential effects of reuptake inhibition of norepinephrine and combined noradrenergic and serotonergic systems on MB, aggression, and oxytocin system changes. Methods: Pregnant Sprague-Dawley rats were treated throughout gestation with saline or one of three doses of either desipramine, which has a high affinity for the norepinephrine monoamine transporter, or amitriptyline, an agent with high affinity for both the norepinephrine and serotonin monoamine transporters. MB and postpartum aggression were assessed on postpartum days 1 and 6 respectively. Oxytocin levels were measured in relevant brain regions on postpartum day 7. Predictions were that amitriptyline would decrease MB and increase aggression relative to desipramine, particularly at higher doses. Amygdaloidal oxytocin was expected to decrease with increased aggression. Results: Amitriptyline and desipramine differentially reduced MB, and at higher doses reduced aggressive behavior. Hippocampal oxytocin levels were lower after treatment with either drug but were not correlated with specific behavioral effects. These results, in combination with previous findings following gestational treatment with other selective neurotransmitter reuptake inhibitors, highlight the diverse effects of multiple monoamine systems thought to be involved in maternal care

    Design, Synthesis, and Evaluation of Tetrasubstituted Pyridines as Potent 5-HT2C Receptor Agonists.

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    A series of pyrido[3,4-d]azepines that are potent and selective 5-HT2C receptor agonists is disclosed. Compound 7 (PF-04781340) is identified as a suitable lead owing to good 5-HT2C potency, selectivity over 5-HT2B agonism, and in vitro ADME properties commensurate with an orally available and CNS penetrant profile. The synthesis of a novel bicyclic tetrasubstituted pyridine core template is outlined, including rationale to account for the unexpected formation of aminopyridine 13 resulting from an ammonia cascade cyclization.We would like to thank the EPSRC (SVL, grant nº EP/K0099494/1 and nº EP/K039520/1) for financial support.This is the accepted manuscript. The final version is available from ACS at http://pubs.acs.org/doi/abs/10.1021/ml500507v

    Effect of ejection fraction on clinical outcomes in patients treated with omecamtiv mecarbil in GALACTIC-HF

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    Background: In GALACTIC-HF (Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure) (n = 8,256), the cardiac myosin activator, omecamtiv mecarbil, significantly reduced the primary composite endpoint (PCE) of time-to-first heart failure event or cardiovascular death in patients with heart failure and reduced ejection fraction (EF) (≤35%). Objectives: The purpose of this study was to evaluate the influence of baseline EF on the therapeutic effect of omecamtiv mecarbil. Methods: Outcomes in patients treated with omecamtiv mecarbil were compared with placebo according to EF. Results: The risk of the PCE in the placebo group was nearly 1.8-fold greater in the lowest EF (≤22%) compared with the highest EF (≥33%) quartile. Amongst the pre-specified subgroups, EF was the strongest modifier of the treatment effect of omecamtiv mecarbil on the PCE (interaction as continuous variable, p = 0.004). Patients receiving omecamtiv mecarbil had a progressively greater relative and absolute treatment effect as baseline EF decreased, with a 17% relative risk reduction for the PCE in patients with baseline EF ≤22% (n = 2,246; hazard ratio: 0.83; 95% confidence interval: 0.73 to 0.95) compared with patients with EF ≥33% (n = 1,750; hazard ratio: 0.99; 95% confidence interval: 0.84 to 1.16; interaction as EF by quartiles, p = 0.013). The absolute reduction in the PCE increased with decreasing EF (EF ≤22%; absolute risk reduction, 7.4 events per 100 patient-years; number needed to treat for 3 years = 11.8), compared with no reduction in the highest EF quartile. Conclusions: In heart failure patients with reduced EF, omecamtiv mecarbil produced greater therapeutic benefit as baseline EF decreased. These findings are consistent with the drug’s mechanism of selectively improving systolic function and presents an important opportunity to improve the outcomes in a group of patients at greatest risk. (Registrational Study With Omecamtiv Mecarbil/AMG 423 to Treat Chronic Heart Failure With Reduced Ejection Fraction [GALACTIC-HF]; NCT02929329

    Omecamtiv mecarbil in Black patients with heart failure and reduced ejection fraction: insights from GALACTIC-HF

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    Background: Omecamtiv mecarbil improves cardiovascular outcomes in patients with heart failure (HF) with reduced ejection fraction (EF). Consistency of drug benefit across race is a key public health topic. Objectives: The purpose of this study was to evaluate the effect of omecamtiv mecarbil among self-identified Black patients. Methods: In GALACTIC-HF (Global Approach to Lowering Adverse Cardiac Outcomes Through Improving Contractility in Heart Failure) patients with symptomatic HF, elevated natriuretic peptides, and left ventricular ejection fraction (LVEF) ≤35% were randomized to omecamtiv mecarbil or placebo. The primary outcome was a composite of time to first event of HF or cardiovascular death. The authors analyzed treatment effects in Black vs White patients in countries contributing at least 10 Black participants. Results: Black patients accounted for 6.8% (n = 562) of overall enrollment and 29% of U.S. enrollment. Most Black patients enrolled in the United States, South Africa, and Brazil (n = 535, 95%). Compared with White patients enrolled from these countries (n = 1,129), Black patients differed in demographics, comorbid conditions, received higher rates of medical therapy and lower rates of device therapies, and experienced higher overall event rates. The effect of omecamtiv mecarbil was consistent in Black vs White patients, with no difference in the primary endpoint (HR = 0.83 vs 0.88, P-interaction = 0.66), similar improvements in heart rate and N-terminal pro–B-type natriuretic peptide, and no significant safety signals. Among endpoints, the only nominally significant treatment-by-race interaction was the placebo-corrected change in blood pressure from baseline in Black vs White patients (+3.4 vs −0.7 mm Hg, P-interaction = 0.02). Conclusions: GALACTIC-HF enrolled more Black patients than other recent HF trials. Black patients treated with omecamtiv mecarbil had similar benefit and safety compared with White counterparts

    Efficacy of omecamtiv mecarbil in heart failure with reduced ejection fraction according to N‐terminal pro‐B ‐type natriuretic peptide level: insights from the GALACTIC‐HF trial

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    Background: N-terminal pro-B-type natriuretic peptide (NT-proBNP) is predictive of both outcomes and response to treatment in patients with heart failure with reduced ejection fraction (HFrEF). Objective: To examine the effect of the cardiac myosin activator omecamtiv mecarbil according to baseline NT-proBNP level in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure trial (GALACTIC-HF). Methods: The primary outcome was the composite of a worsening HF event (urgent clinic visit, emergency department visit, or hospitalization) or cardiovascular death. We prespecified analysis of the effect of treatment according to baseline NT-proBNP (≤median, >median), excluding individuals with AF/AFL. Results: Of the 8232 patients analyzed, 8206 had an available baseline NT-proBNP measurement. Among the 5971 patients not in AF/AFL, the median (Q1, Q3) NT-proBNP level was 1675 (812–3579) pg/ml. Hazard ratios (HR) for the effect of omecamtiv mecarbil, compared with placebo, for the primary endpoint in patients without AF/AFL were: ≤median 0.94 (95% CI, 0.80–1.09), >median 0.81 (0.73–0.90) [P-interaction = 0.095]; for the overall population (including patients with AF/AFL) the HRs were ≤ median 1.01 (0.90–1.15) and > median 0.88 (0.80–0.96) [P-interaction = 0.035]. There was an interaction between treatment and NT-proBNP, examined as a continuous variable, with greater effect of omecamtiv mecarbil on the primary outcome in patients with a higher baseline NT-proBNP (P-interaction = 0.086). Conclusions: In GALACTIC-HF, the benefit of omecamtiv mecarbil appeared to be larger in patients with higher baseline NT-proBNP levels, especially in patients without AF/AFL
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