Coordinated inhibition of actin-induced platelet aggregation by plasma gelsolin and vitamin D-binding protein

Actin is an abundant intracellular protein that is released into the blood during tissue injury and its injection into rats causes microthrombi to form in the vasculature. This report and others have shown that actin filaments are able to aggregate platelets in an adenosine diphosphate (ADP)-dependent manner. The effects on this process of two plasma actin-binding proteins, vitamin D-binding protein (DBP) and gelsolin, were examined separately and together. The addition of DBP, a monomer-binding protein, to actin filaments did not affect their ability to induce platelet aggregation. However, severing of actin filaments with gelsolin resulted in an increased degree of platelet aggregation. Preincubation of F-actin with both gelsolin and DBP resulted in a significant inhibition of aggregation. The effects of DBP and gelsolin on actin-induced aggregation paralleled their effects on exchange of actin-bound adenine nucleotides. DBP inhibited 1, N6- ethenoadenosine 5' triphosphate (epsilon-ATP) exchange with G-actin but not with F-actin. Gelsolin increased epsilon-ATP exchange with F-actin, which was largely abrogated by the addition of DBP. These results suggest that gelsolin's severing (and subsequent capping) of actin filaments not only results in an increase in the number of pointed filament ends but also in the dissociation of actin monomers containing ADP. Phalloidin, which stabilizes actin filaments while decreasing both monomer and nucleotide exchange, inhibited actin-induced aggregation, as well, indicating that depolymerization of actin filaments is not required to inhibit aggregation. Platelet activation by either G- or F- actin may thus be regulated by the local concentrations of the plasma actin-binding proteins gelsolin and DBP. Together, these proteins inhibit platelet aggregation in a manner that can be explained by their effects on actin's filament structure and the accessibility of its bound ADP. Depletion of DBP or gelsolin may allow actin released from injured tissues to stimulate purinergic receptors on platelets, and perhaps other cells, via its bound adenine nucleotides.     

Quantitation of erythropoietin-producing cells in kidneys of mice by in situ hybridization: correlation with hematocrit, renal erythropoietin mRNA, and serum erythropoietin concentration

In situ hybridization was used to quantitate the cells that produce erythropoietin (EP) in the renal cortices of mice with varying severities of acute anemia and of mice recovering from severe, acute anemia. The number of EP-producing cells in the renal cortex increased in an exponential manner as hematocrit was decreased. Individual EP- producing cells had very similar densities of silver grains in autoradiograms regardless of whether they were from normal mice or from slightly, moderately or severely anemic animals. With increasingly severe anemia, total renal EP mRNA levels and serum EP concentrations showed increases that correlated with the number of renal EP-producing cells. These results indicate that as mice become more anemic, additional cells are recruited to produce EP rather than the cells already producing EP being stimulated to increase their individual production. In mildly and moderately anemic animals, small clusters of EP-producing cells were found in the inner cortex with large areas of cortex containing no EP-producing cells. In severely anemic mice, EP- producing cells were found throughout the inner cortex with only a very few found scattered in the outer cortex and outer medulla. The data indicate that only a subset of total renal interstitial cells produce EP. During recovery from severe, acute anemia, the numbers of EP- producing cells decreased exponentially as hematocrits rose and correlated with decreases in total renal EP mRNA and serum EP concentrations. These results suggest that following an acute blood loss and during the recovery from a blood loss, the capacity to deliver oxygen, as represented by hematocrit, is the major regulator of EP production.     

Randomized,Double-Blind,Placebo-Controlled Study of Encenicline,an α7 Nicotinic Acetylcholine Receptor Agonist,as a Treatment for Cognitive Impairment in Schizophrenia

Encenicline is a novel, selective α7 nicotinic acetylcholine receptor agonist in development for treating cognitive impairment in schizophrenia and Alzheimer''s disease. A phase 2, double-blind, randomized, placebo-controlled, parallel-design, multinational study was conducted. Patients with schizophrenia on chronic stable atypical antipsychotics were randomized to encenicline 0.27 or 0.9 mg once daily or placebo for 12 weeks. The primary efficacy end point was the Overall Cognition Index (OCI) score from the CogState computerized battery. Secondary end points include MATRICS Consensus Cognitive Battery (MCCB) (in US patients), the Schizophrenia Cognition Rating Scale (SCoRS) total score, SCoRS global rating, and Positive and Negative Syndrome Scale (PANSS) total and subscale and cognition factor scores. Of 319 randomized patients, 317 were included in the safety population, and 307 were included in the intent-to-treat population. Notable trends in improvement were demonstrated across all cognition scales. For the OCI score, the LS mean difference for encenicline 0.27 mg vs placebo was significant (Cohen''s d=0.257; P=0.034). Mean SCoRS total scores decreased showing improvement in function over time, and the difference was significant for encenicline 0.9 mg vs placebo (P=0.011). Furthermore, the difference between encenicline 0.9 mg and placebo was significant for the PANSS Cognition Impairment Domain (P=0.0098, Cohen''s d=0.40) and for the PANSS Negative scale (P=0.028, Cohen''s d=0.33). Treatment-emergent adverse events were reported at similar frequencies across all treatment groups (39.0% with placebo, 23.4% with encenicline 0.27 mg, and 33.3% with encenicline 0.9 mg). Overall, encenicline was generally well tolerated and demonstrated clinically meaningful improvements in cognition and function in patients with schizophrenia.     

Evidence of Diagnostic and Treatment Delay in Seronegative Rheumatoid Arthritis: Missing the Window of Opportunity

ObjectivesTo compare the time from first joint swelling to fulfillment of the American College of Rheumatology/European League Against Rheumatism classification criteria between patients with seropositive and seronegative rheumatoid arthritis (RA) and to assess the impact of seronegative status on the time from first joint swelling to initiation of disease-modifying antirheumatic drug (DMARD) therapy and achievement of remission.Patients and MethodsTimes from first provider-documented joint swelling to fulfillment of the 1987 and 2010 American College of Rheumatology/European League Against Rheumatism criteria and to the clinical diagnosis of RA were measured in a population-based cohort of adults with incident RA between January 1, 2009, and December 31, 2014. Disease characteristics and achievement of remission were compared between seropositive (rheumatoid factor positive and/or anti–citrullinated peptide antibody positive) and seronegative (rheumatoid factor negative/anti–citrullinated peptide antibody negative) patients.ResultsThe median time from first joint swelling to fulfillment of the 1987 (48 [interquartile range (IQR), 0-300] days vs 2 [IQR, 0-45] days; P=.001) and 2010 (14 [IQR, 0-196] days vs 0 [IQR, 0-29] days; P=.004) classification criteria and the median time from first joint swelling to the clinical diagnosis of RA (187 [IQR, 13-503] days vs 11 [IQR, 0-76] days; P<.001) were significantly longer in seronegative patients than in seropositive patients. The median time from first joint swelling to first prescribed DMARD therapy was significantly longer in seronegative patients (40 [IQR, 5-199] days vs 14 [IQR, 0-73] days; P=.01). Patients with seronegative RA were less likely to achieve remission (28% vs 50% at 5 years after fulfillment of the 2010 criteria; P=.007), but there was no difference when the patient global score was removed from the remission definition.ConclusionPatients with seronegative RA experienced a delay in diagnosis, according to both the 1987 and 2010 classification criteria, as well as a delay in the initiation of DMARD therapy. Patients with seronegative RA were also less likely to attain remission, suggesting that the window of opportunity for intervention may be more frequently missed in this group.     

The effects and effectiveness of electromotive drug administration and chemohyperthermia for treating non-muscle invasive bladder cancer

Introduction

Preliminary studies show that device assisted intravesical therapies appear more effective than passive diffusion intravesical therapy for the treatment of non-muscle invasive bladder cancer (NMIBC) in specific settings, and phase III studies are now being conducted. Consequently, we have undertaken a non-systematic review with the objective of describing the scientific basis and mechanisms of action of electromotive drug administration (EMDA) and chemohyperthermia (CHT).

Methods

PubMed, ClinicalTrials.gov and the Cochrane Library were searched to source evidence for this non-systematic review. Randomised controlled trials, systematic reviews and meta-analyses were evaluated. Publications regarding the scientific basis and mechanisms of action of EMDA and CHT were identified, as well as clinical studies to date.

Results

EMDA takes advantage of three phenomena: iontophoresis, electro-osmosis and electroporation. It has been found to reduce recurrence rates in NMIBC patients and has been proposed as an addition or alternative to bacillus Calmette–Guérin (BCG) therapy in the treatment of high risk NMIBC. CHT improves the efficacy of mitomycin C by three mechanisms: tumour cell cytotoxicity, altered tumour blood flow and localised immune responses. Fewer studies have been conducted with CHT than with EMDA but they have demonstrated utility for increasing disease-free survival, especially in patients who have previously failed BCG therapy.

Conclusions

It is anticipated that EMDA and CHT will play important roles in the management of NMIBC in the future. Techniques of delivery should be standardised, and there is a need for more randomised controlled trials to evaluate the benefits of the treatments alongside quality of life and cost-effectiveness.     

Use of the surgical Apgar score to guide postoperative care

Introduction

The surgical Apgar score (SAS) can predict 30-day major complications or death after surgery. Studies have validated the score in different patient populations and suggest it should be used to objectively guide postoperative care. We aimed to see whether using the SAS in a decisive approach in a future randomised controlled trial (RCT) would be likely to demonstrate an effect on postoperative care and clinical outcome.

Methods

A total of 143 adults undergoing general/vascular surgery in 9 National Health Service hospitals were recruited to a pilot single blinded RCT and the data for 139 of these were analysed. Participants were randomised to a control group with standard postoperative care or to an intervention group with care influenced (but not mandated) by the SAS (decisive approach). The notional primary outcome was 30-day major complications or death.

Results

Incidence of major complications was similar in both groups (control: 20/69 [29%], intervention: 23/70 [33%], p=0.622). Immediate admissions to the critical care unit was higher in the intervention group, especially in the SAS 0–4 subgroup (4/6 vs 2/7) although this was not statistically significant (p=0.310). Validity was also confirmed in area under the curve (AUC) analysis (AUC: 0.77).

Conclusions

This pilot study found that a future RCT to investigate the effect of using the SAS in a decisive approach may demonstrate a difference in postoperative care. However, significant changes to the design are needed if differences in clinical outcome are to be achieved reliably. These would include a wider array of postoperative interventions implemented using a quality improvement approach in a stepped wedge cluster design with blinded collection of outcome data.     

Systems Science and Obesity Policy: A Novel Framework for Analyzing and Rethinking Population-Level Planning

Objectives. We demonstrate the use of a systems-based framework to assess solutions to complex health problems such as obesity.Methods. We coded 12 documents published between 2004 and 2013 aimed at influencing obesity planning for complex systems design (9 reports from US and Canadian governmental or health authorities, 1 Cochrane review, and 2 Institute of Medicine reports). We sorted data using the intervention-level framework (ILF), a novel solutions-oriented approach to complex problems. An in-depth comparison of 3 documents provides further insight into complexity and systems design in obesity policy.Results. The majority of strategies focused mainly on changing the determinants of energy imbalance (food intake and physical activity). ILF analysis brings to the surface actions aimed at higher levels of system function and points to a need for more innovative policy design.Conclusions. Although many policymakers acknowledge obesity as a complex problem, many strategies stem from the paradigm of individual choice and are limited in scope. The ILF provides a template to encourage natural systems thinking and more strategic policy design grounded in complexity science.Obesity is widely recognized as a complex problem emerging from a system composed of many diverse, interacting variables.1–3 Several factors make the obesity system difficult to shift, including but not limited to the presence of feedback loops and delays; an abundance of nonlinear, overlapping interdependencies; and the heterogeneity of individuals and organizations.1,4 Policymakers and planners have responded to the obesity epidemic by producing a large number of frameworks, strategies, and action plans. Although past efforts have been criticized for emphasizing individual lifestyle change as the solution,5,6 recent efforts have embraced socioecological models of intervention, emphasizing the obesogenic environment and its impact on individual weight gain.3,7 The many options available to policymakers have the potential to result in what Lang and Rayner6^(p166) termed a “policy cacophony” of noise drowning out effort.Efforts to shift the systems that support the emergence of chronic disease and obesity are starting to benefit from a focused effort to apply systems science,8 as has been done with other pressing public health issues such as tobacco.9 Obesity, tied up with difficult ideological and political questions regarding responsibility and stigma,10–13 is a particularly wicked social problem for which reductionist science may be less helpful. Systems science can complement socioecological models of health promotion by examining not just the causes of obesity but also interactions across its contributing subsystems.14 The UK government’s Foresight program contributed to the perception of obesity as a complex problem with the development of an obesity system map highlighting the diversity of factors involved in subsystems such as food production and consumption, individual physical activity and the physical activity environment, social and individual psychology, and physiology.4 The heuristic value of the Foresight map in demonstrating the complexity of obesity and the interdependencies between the system’s variables is an example of a systems science tool that may help to advance the conversation about what actions need to be taken.Although the Foresight map helps to focus dialogue on the complex nature of obesity, it does not immediately lead to discussion of solutions appropriate for this complex problem. We recently developed a systems science framework that may be a useful and accessible means of operationalizing systems thinking toward solutions. The intervention-level framework (ILF) was adapted from Donella Meadows’15 list of 12 places to intervene in complex systems. Meadows, a pioneering environmental scientist, spent decades analyzing the complexities of economic growth and environmental sustainability, and she grew frustrated with the unintended consequences that resulted when simple solutions were applied to complex problems. We collapsed the original 12 points of intervention into 5 more mutually exclusive levels that retain all of the original ideas but allow for the sorting of content in a reproducible fashion. These levels account for system operation at the levels of paradigm, goals, system structure, feedback and delays, and structural elements. To date, the ILF has been used in framework analyses of content concerning actions to improve food systems, wherein it was useful in elucidating points of conflict and convergence to make them more healthy, green, fair, and affordable.16In this article, we explore the application of the ILF to the obesity system by analyzing recent strategies and reports aimed at influencing policy and planning. Our interest was in developing a deeper, more integrated understanding of how best to act in addressing the complex problem of obesity. Using a systems lens, we sought to advance our understanding of the various system levels and the specific interventions required to support large-scale change. We also sought to further the application of systems-based frameworks in the analysis of complex health problems in a manner accessible to public health practitioners and policymakers lacking expertise in systems science methodologies.     

The malignant cells in a Lennert's lymphoma are T lymphocytes with a mature helper surface phenotype. A multiparameter flow cytometric analysis

The flow cytometric analysis of DNA content in cells obtained from a case of Lennert's lymphoma demonstrated the presence of a discrete hypotetraploid cell population. Correlated multiparameter analysis of DNA, light scatter, and surface antigens by flow cytometry showed that the hypotetraploid cells were intermediate to large cells expressing T11, T3, and T4 antigens and lacking B1 and T8 antigens. These findings suggest that Lennert's lymphoma represents a malignant neoplasm of T- helper lymphocytes.