Density-Dependent Regulation of Brook Trout Population Dynamics along a Core-Periphery Distribution Gradient in a Central Appalachian Watershed

Spatial population models predict strong density-dependence and relatively stable population dynamics near the core of a species\u27 distribution with increasing variance and importance of density-independent processes operating towards the population periphery. Using a 10-year data set and an information-theoretic approach, we tested a series of candidate models considering density-dependent and density-independent controls on brook trout population dynamics across a core-periphery distribution gradient within a central Appalachian watershed. We sampled seven sub-populations with study sites ranging in drainage area from 1.3–60 km2and long-term average densities ranging from 0.335–0.006 trout/m. Modeled response variables included per capita population growth rate of young-of-the-year, adult, and total brook trout. We also quantified a stock-recruitment relationship for the headwater population and coefficients of variability in mean trout density for all sub-populations over time. Density-dependent regulation was prevalent throughout the study area regardless of stream size. However, density-independent temperature models carried substantial weight and likely reflect the effect of year-to-year variability in water temperature on trout dispersal between cold tributaries and warm main stems. Estimated adult carrying capacities decreased exponentially with increasing stream size from 0.24 trout/m in headwaters to 0.005 trout/m in the main stem. Finally, temporal variance in brook trout population size was lowest in the high-density headwater population, tended to peak in mid-sized streams and declined slightly in the largest streams with the lowest densities. Our results provide support for the hypothesis that local density-dependent processes have a strong control on brook trout dynamics across the entire distribution gradient. However, the mechanisms of regulation likely shift from competition for limited food and space in headwater streams to competition for thermal refugia in larger main stems. It also is likely that source-sink dynamics and dispersal from small headwater habitats may partially influence brook trout population dynamics in the main stem

Surface Mol (CD11b/CD18) glycoprotein is up-modulated by neutrophils recruited to sites of inflammation in vivo

Inasmuch as the recruitment of polymorphonuclear leukocytes (PMNs) to inflammatory foci in vivo involves adhesion-dependent events (e.g., margination, diapedesis, and directed migration), we sought to characterize the relationship between the local accumulation of PMNs in sterile peritonitis and their surface expression of the adhesion-promoting plasma membrane glycoprotein. Mol (CD11b/ CD18). In an immunofluorescence analysis of PMNs isolated from rats injected intraperitoneally with sterile 1% glycogen solution, we detected a significant enhancement of surface Mol expression by exudative peritoneal PMNs. In contrast, no significant rise in Mol expression was noted over time by circulating intravascular PMNs (isolated simultaneously). However, these intravascular PMNs had the capacity to increase their surface Mol density upon exposure to peritoneal fiuid supernatant at 37°C. These results demonstrate that PMNs at sites of inflammation in vivo do up-modulate their surface expression of the adhesion-promoting Mol glycoprotein during their recruitment from the circulating, intravascular leukocyte pool.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44502/1/10753_2004_Article_BF00916757.pd

Consensus-based care recommendations for adults with myotonic dystrophy type 1

Purpose of review Myotonic dystrophy type 1 (DM1) is a severe, progressive genetic disease that affects between 1 in 3,000 and 8,000 individuals globally. No evidence-based guideline exists to inform the care of these patients, and most do not have access to multidisciplinary care centers staffed by experienced professionals, creating a clinical care deficit. Recent findings The Myotonic Dystrophy Foundation (MDF) recruited 66 international clinicians experienced in DM1 patient care to develop consensus-based care recommendations. MDF created a 2-step methodology for the project using elements of the Single Text Procedure and the Nominal Group Technique. The process generated a 4-page Quick Reference Guide and a comprehensive, 55-page document that provides clinical care recommendations for 19 discrete body systems and/or care considerations. Summary The resulting recommendations are intended to help standardize and elevate care for this patient population and reduce variability in clinical trial and study environments. Described as “one of the more variable diseases found in medicine,” myotonic dystrophy type 1 (DM1) is an autosomal dominant, triplet-repeat expansion disorder that affects somewhere between 1:3,000 and 1:8,000 individuals worldwide.1 There is a modest association between increased repeat expansion and disease severity, as evidenced by the average age of onset and overall morbidity of the condition. An expansion of over 35 repeats typically indicates an unstable and expanding mutation. An expansion of 50 repeats or higher is consistent with a diagnosis of DM1. DM1 is a multisystem and heterogeneous disease characterized by distal weakness, atrophy, and myotonia, as well as symptoms in the heart, brain, gastrointestinal tract, endocrine, and respiratory systems. Symptoms may occur at any age. The severity of the condition varies widely among affected individuals, even among members of the same family. Comprehensive evidence-based guidelines do not currently exist to guide the treatment of DM1 patients. As a result, the international patient community reports varied levels of care and care quality, and difficulty accessing care adequate to manage their symptoms, unless they have access to multidisciplinary neuromuscular clinics. Consensus-based care recommendations can help standardize and improve the quality of care received by DM1 patients and assist clinicians who may not be familiar with the significant variability, range of symptoms, and severity of the disease. Care recommendations can also improve the landscape for clinical trial success by eliminating some of the inconsistencies in patient care to allow more accurate understanding of the benefit of potential therapies

Using social and behavioural science to support COVID-19 pandemic response

The COVID-19 pandemic represents a massive global health crisis. Because the crisis requires large-scale behaviour change and places significant psychological burdens on individuals, insights from the social and behavioural sciences can be used to help align human behavior with the recommendations of epidemiologists and public health experts. Here we discuss evidence from a selection of research topics relevant to pandemics, including work on navigating threats, social and cultural influences on behaviour, science communication, moral decision-making, leadership, and stress and coping. In each section, we note the nature and quality of prior research, including uncertainty and unsettled issues. We identify several insights for effective response to the COVID-19 pandemic, and also highlight important gaps researchers should move quickly to fill in the coming weeks and months

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2–4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Conservation planning at the intersection of landscape and climate change: brook trout in the Chesapeake Bay watershed

We developed a multi‐scale conservation planning framework for brook trout (Salvelinus fontinalis ) within the Chesapeake Bay watershed that incorporates both land use and climate stressors. Our specific objectives were to (1) construct a continuous spatial model of brook trout distribution and habitat quality at the stream reach scale; (2) characterize brook trout vulnerability to climate change under a range of future climate scenarios; and (3) identify multi‐scale restoration and protection priorities for brook trout across the Chesapeake Bay watershed. Boosted regression tree analysis predicted brook trout occurrence at the stream reach scale with a high degree of accuracy (CV AUC = 0.92) as a function of both natural (e.g., water temperature and precipitation) and anthropogenic (e.g., agriculture and urban development) landscape and climatic attributes. Current land use activities result in a predicted loss of occurrence in over 11,000 stream segments (40% of suitable habitat) and account for over 15,000 km (45% of current value) of lost functional brook trout fishery value (i.e., length‐weighted occurrence probability) in the Chesapeake Bay watershed. Climate change (increased ambient temperatures and altered precipitation) is projected to result in a loss of occurrence in at least 3000 additional segments (19% of current value) and at least 3000 km of functional fishery value (9% of current value) by 2062. Model outcomes were used to identify low‐ and high‐quality stream segments within relatively intact and degraded sub‐watersheds as restoration and protection priorities, respectively, and conservation priorities were targeted in watersheds with high projected resilience to climate change. Our results suggest that traditional restoration activities, such as habitat enhancement, riparian management, and barrier removal, may be able to recover a substantial amount of brook trout habitat lost to historic landscape change. However, restoration efforts must be designed within the context of expected impacts from climate change or those efforts may not produce long‐term benefits to brook trout in this region

Results from candidate models using AIC_c for the 7 study sites.

<p>Only interpretable predictor variables in at least one site are provided (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0091673#pone.0091673.s002" target="_blank">Table S2</a> for all models analyzed). The first value represents the Akaike's weight (<i>w_i</i>) given to each model in the candidate set followed by the <i>R²</i> statistic and the direction of the relationship. Bold values represent the best model in each candidate set. Abbreviations are as follows: rpop  =  per capita growth rate (r = ln(n_t/n_t−1) for the total brook trout population, radult  = r for adults, ryoy  = r for young-of-the-year, dtrout  =  density of all brook trout, dadult  =  density of adult brook trout, dyoy  =  density of young-of-the-year brook trout, sp_tT  =  mean April-June maximum temperature, su_t-1T  =  mean July maximum temperature, and sp_tQ  =  mean March-June discharge. Missing values represent predictor variables that were correlated with another predictor variable in the candidate set and therefore removed. No models were constructed for ryoy at main stem sites because few YOY were found in those sites. Models with an * were considered interpretable models using criteria from Grossman et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0091673#pone.0091673-Grossman1" target="_blank">[14]</a>.</p