75 research outputs found
Distribution and Activity of Bacteria in the Headwaters of the Rhode River Estuary, Maryland, USA
Abstract: A transect along the axis of the headwaters of a tidal estuary was sampled for microbial, nutrient, and physical parameters. Chlorophyll a averaged 42 μg 1 -1 and phytoplankton comprised an estimated 80% of the total microbial biomass as determined by adenosine triphosphate (ATP). Bacterial concentrations ranged from 0.3-53.9 × 10 6 cells ml -1 and comprised about 4% of the total living microbial biomass. Bacterial production, determined by 3H-methyl-thymidine incorporation was about 0.05-2.09 × 10 9 cells 1 -1 h -1 , with specific growth rates of 0.26-1.69 d -1 . Most bacterial production was retained on 0.2 μm pore size filters, but passed through 1.0 μm filters. Significant positive correlations were found between all biomass measures and most nutrient measures with the exception of dissolved inorganic nitrogen nutrients where correlations were negative. Seasonal variability was evident in all parameters and variability among the stations was evident in most. The results suggest that bacterial production requires a significant carbon input, likely derived from autotrophic production, and that microbial trophic interactions are important. Article: Introduction Coastal and estuarine systems are sites where competition for nutrients by microorganisms and remineralization of photosynthetically fixed carbon are important processes. High rates of bacterial activity have been found in such systems for both inorganic nutrients and organic compounds Utilization of carbon fixed by primary production is a primary role of heterotrophic microorganisms, and recent studies suggest that the magnitude of this role has been underestimated Estuarine systems may exhibit even greater dependence upon trophic links through microheterotrophs tha
Population pharmacokinetics of fluconazole in critically ill patients receiving continuous venovenous hemodiafiltration - using Monte Carlo Simulations to predict doses for specified pharmacodynamic targets
Fluconazole is a widely used antifungal agent that is extensively reabsorbed in patients with normal renal function. However, its reabsorption can be compromised in patients with acute kidney injury, thereby leading to altered fluconazole clearance and total systemic exposure. Here, we explore the pharmacokinetics of fluconazole in 10 critically ill anuric patients receiving continuous venovenous hemodiafiltration (CVVHDF). We performed Monte Carlo simulations to optimize dosing to appropriate pharmacodynamic endpoints for this population. Pharmacokinetic profiles of initial and steady-state doses of 200 mg intravenous fluconazole twice daily were obtained from plasma and CVVHDF effluent. Nonlinear mixed-effects modeling (NONMEM) was used for data analysis and to perform Monte Carlo simulations. For each dosing regimen, the free drug area under the concentration-time curve (fAUC)/MIC ratio was calculated. The percentage of patients achieving an AUC/MIC ratio greater than 25 was then compared for a range of MIC values. A two-compartment model adequately described the disposition of fluconazole in plasma. The estimate for total fluconazole clearance was 2.67 liters/h and was notably 2.3 times faster than previously reported in healthy volunteers. Of this, fluconazole clearance by the CVVHDF route (CL(CVVHDF)) represented 62% of its total systemic clearance. Furthermore, the predicted efficiency of CL(CVVHDF) decreased to 36.8% when filters were in use >48 h. Monte Carlo simulations demonstrated that a dose of 400 mg twice daily maximizes empirical treatment against fungal organisms with MIC up to 16 mg/liter. This is the first study we are aware of that uses Monte Carlo simulations to inform dosing requirements in patients where tubular reabsorption of fluconazole is probably nonexistent
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A behavioral comparison of male and female adults with high functioning autism spectrum conditions
Autism spectrum conditions (ASC) affect more males than females in the general population. However, within ASC it is unclear if there are phenotypic sex differences. Testing for similarities and differences between the sexes is important not only for clinical assessment but also has implications for theories of typical sex differences and of autism. Using cognitive and behavioral measures, we investigated similarities and differences between the sexes in age- and IQ-matched adults with ASC (high-functioning autism or Asperger syndrome). Of the 83 (45 males and 38 females) participants, 62 (33 males and 29 females) met Autism Diagnostic Interview-Revised (ADI-R) cut-off criteria for autism in childhood and were included in all subsequent analyses. The severity of childhood core autism symptoms did not differ between the sexes. Males and females also did not differ in self-reported empathy, systemizing, anxiety, depression, and obsessive-compulsive traits/symptoms or mentalizing performance. However, adult females with ASC showed more lifetime sensory symptoms (p = 0.036), fewer current socio-communication difficulties (p = 0.001), and more self-reported autistic traits (p = 0.012) than males. In addition, females with ASC who also had developmental language delay had lower current performance IQ than those without developmental language delay (p<0.001), a pattern not seen in males. The absence of typical sex differences in empathizing-systemizing profiles within the autism spectrum confirms a prediction from the extreme male brain theory. Behavioral sex differences within ASC may also reflect different developmental mechanisms between males and females with ASC. We discuss the importance of the superficially better socio-communication ability in adult females with ASC in terms of why females with ASC may more often go under-recognized, and receive their diagnosis later, than males
Linkages Over Time Between Adolescents' Relationships with Parents and Friends
This 5-wave longitudinal study examines linkages over time between adolescents’ perceptions of relationships with parents and friends with respect to support, negative interaction, and power. A total of 575 early adolescents (54.1% boys) and 337 middle adolescents (43.3% boys) participated. Path analyses mainly showed bidirectional associations between adolescents’ perceptions of parent–adolescent relationships and friendships with a predominantly stronger influence from parent–adolescent relationships to friendships than vice versa in early to middle adolescence and an equal mutual influence in middle to late adolescence. The findings support the theoretical ideas that perceptions of relationships with parents generalize to perceptions of relationships with friends and that relationship skills and principles of adolescent friendships generalize to relationships with parents. Furthermore, the results indicate that the influence of parents decreases, whereas the influence of friends increases, and that both social worlds become equally important and overlapping towards late adolescence
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The adaptive designs CONSORT extension (ACE) statement: a checklist with explanation and elaboration guideline for reporting randomised trials that use an adaptive design
Abstract: Adaptive designs (ADs) allow pre-planned changes to an ongoing trial without compromising the validity of conclusions and it is essential to distinguish pre-planned from unplanned changes that may also occur. The reporting of ADs in randomised trials is inconsistent and needs improving. Incompletely reported AD randomised trials are difficult to reproduce and are hard to interpret and synthesise. This consequently hampers their ability to inform practice as well as future research and contributes to research waste. Better transparency and adequate reporting will enable the potential benefits of ADs to be realised. This extension to the Consolidated Standards Of Reporting Trials (CONSORT) 2010 statement was developed to enhance the reporting of randomised AD clinical trials. We developed an Adaptive designs CONSORT Extension (ACE) guideline through a two-stage Delphi process with input from multidisciplinary key stakeholders in clinical trials research in the public and private sectors from 21 countries, followed by a consensus meeting. Members of the CONSORT Group were involved during the development process. The paper presents the ACE checklists for AD randomised trial reports and abstracts, as well as an explanation with examples to aid the application of the guideline. The ACE checklist comprises seven new items, nine modified items, six unchanged items for which additional explanatory text clarifies further considerations for ADs, and 20 unchanged items not requiring further explanatory text. The ACE abstract checklist has one new item, one modified item, one unchanged item with additional explanatory text for ADs, and 15 unchanged items not requiring further explanatory text. The intention is to enhance transparency and improve reporting of AD randomised trials to improve the interpretability of their results and reproducibility of their methods, results and inference. We also hope indirectly to facilitate the much-needed knowledge transfer of innovative trial designs to maximise their potential benefits. In order to encourage its wide dissemination this article is freely accessible on the BMJ and Trials journal websites.“To maximise the benefit to society, you need to not just do research but do it well” Douglas G Altma
Unique Roles of Mothering and Fathering in Child Anxiety; Moderation by Child’s Age and Gender
We examined the associations between the parenting dimensions autonomy granting, over control, and rejection and children’s anxiety, in relation to parent and child gender and child age. Elementary school-aged children (n = 179, Mage = 10.27, SD = 1.30), adolescents (n = 127, Mage = 15.02, SD = 1.54) and both their parents completed questionnaires on parenting and children’s anxiety. Parenting was more strongly related to child anxiety in elementary school children than in adolescents. Maternal over control was uniquely related to elementary school-aged children’s anxiety whereas paternal over control was more important during adolescence. Opposite to our expectations, we found higher levels of parental autonomy granting to be related to higher levels of anxiety for younger elementary school-aged children (age < 10). For adolescents, the association between paternal over control and anxiety was stronger for older adolescents (age > 15), with higher levels of over control related to higher levels of anxiety. For both elementary school-aged children and adolescents, the associations between parenting and child anxiety did not differ as a function of the child’s gender. If we are to understand the associations between parenting and children’s anxiety, it is important to distinguish parental autonomy granting from parental over control and to consider the role of parent gender and the age of the child
Does Father Know Best? A Formal Model of the Paternal Influence on Childhood Social Anxiety
We explore paternal social anxiety as a specific risk factor for childhood social anxiety in a rational optimization model. In the course of human evolution, fathers specialized in external protection (e.g., confronting the external world) while mothers specialized in internal protection (e.g., providing comfort and food). Thus, children may instinctively be more influenced by the information signaled by paternal versus maternal behavior with respect to potential external threats. As a result, if fathers exhibit social anxiety, children interpret it as a strong negative signal about the external social world and rationally adjust their beliefs, thus becoming stressed. Under the assumption that paternal signals on social threats are more influential, a rational cognitive inference leads children of socially anxious fathers to develop social anxiety, unlike children of socially anxious mothers. We show in the model that mothers cannot easily compensate for anxious paternal behavior, but choose to increase maternal care to maintain the child’s wellbeing. We discuss research directions to test the proposed model as well as implications for the prevention and treatment of child social anxiety
RA-MAP, molecular immunological landscapes in early rheumatoid arthritis and healthy vaccine recipients
Rheumatoid arthritis (RA) is a chronic inflammatory disorder with poorly defined aetiology characterised by synovial inflammation with variable disease severity and drug responsiveness. To investigate the peripheral blood immune cell landscape of early, drug naive RA, we performed comprehensive clinical and molecular profiling of 267 RA patients and 52 healthy vaccine recipients for up to 18 months to establish a high quality sample biobank including plasma, serum, peripheral blood cells, urine, genomic DNA, RNA from whole blood, lymphocyte and monocyte subsets. We have performed extensive multi-omic immune phenotyping, including genomic, metabolomic, proteomic, transcriptomic and autoantibody profiling. We anticipate that these detailed clinical and molecular data will serve as a fundamental resource offering insights into immune-mediated disease pathogenesis, progression and therapeutic response, ultimately contributing to the development and application of targeted therapies for RA.</p
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