Advances in Vascular Diagnostics using Magnetic Particle Imaging (MPI) for Blood Circulation Assessment.

Rapid and accurate assessment of conditions characterized by altered blood flow, cardiac blood pooling, or internal bleeding is crucial for diagnosing and treating various clinical conditions. While widely used imaging modalities such as magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound offer unique diagnostic advantages, they fall short for specific indications due to limited penetration depth and prolonged acquisition times. Magnetic particle imaging (MPI), an emerging tracer-based technique, holds promise for blood circulation assessments, potentially overcoming existing limitations with reduction in background signals and high temporal and spatial resolution, below the millimeter scale. Successful imaging of blood pooling and impaired flow necessitates tracers with diverse circulation half-lives optimized for MPI signal generation. Recent MPI tracers show potential in imaging cardiovascular complications, vascular perforations, ischemia, and stroke. The impressive temporal resolution and penetration depth also position MPI as an excellent modality for real-time vessel perfusion imaging via functional MPI (fMPI). This review summarizes advancements in optimized MPI tracers for imaging blood circulation and analyzes the current state of pre-clinical applications. This work discusses perspectives on standardization required to transition MPI from a research endeavor to clinical implementation and explore additional clinical indications that may benefit from the unique capabilities of MPI.

Silk Fibroin Particles as Carriers in the Development of All-Natural Hemoglobin-Based Oxygen Carriers (HBOCs).

Oxygen therapeutics have a range of applications in transfusion medicine and disease treatment. Synthetic molecules and all-natural or semi-synthetic hemoglobin-based oxygen carriers (HBOCs) have seen success as potential circulating oxygen carriers. However, many early HBOC products were removed from the market due to side effects from excess hemoglobin in the blood stream and hemoglobin entering the tissue. To overcome these issues, research has focused on increasing the molecular diameter of hemoglobin by polymerizing hemoglobin molecules or encapsulating hemoglobin in liposomal carriers, where immune responses and circulation times remain a challenge. This work looks to leverage the properties of silk fibroin, a cytocompatible and non-thrombogenic biopolymer, known to entrap protein-based cargo, to engineer a silk fibroin-hemoglobin-based oxygen carrier (sfHBOC). Herein, an all-aqueous solvent evaporation technique was used to form silk fibroin particles with and without hemoglobin to tailor the formulation for specific particle sizes. The encapsulation efficiency and ferrous state of hemoglobin were analyzed, resulting in 60% encapsulation efficiency and a maximum of 20% ferric hemoglobin, yielding 100 µg/mL active hemoglobin in certain sfHBOC formulations. The system did not elicit a strong inflammation response in vitro, demonstrating the potential for this particle system to serve as an injectable HBOC.

Silk Fibroin Particles as Carriers in the Development of Hemoglobin-Based Oxygen Carriers.

Oxygen therapeutics have a range of applications in transfusion medicine and disease treatment. Synthetic molecules and all-natural or semi-synthetic hemoglobin-based oxygen carriers (HBOCs) have seen success as potential circulating oxygen carriers. However, many early HBOC products stalled in development due to side effects from excess hemoglobin in the blood stream and hemoglobin entering the tissue. To overcome these issues, research has focused on increasing the molecular diameter of hemoglobin by polymerizing hemoglobin molecules or encapsulating hemoglobin in liposomal carriers. This work leverages the properties of silk fibroin, a cytocompatible and non-thrombogenic biopolymer, known to entrap protein-based cargo, to engineer a fully protein-based oxygen carrier. Herein, an all-aqueous solvent evaporation technique was used to form silk particles via phase separation from a bulk polyvinyl alcohol phase (PVA). Particles size was tuned, and particles were formed with and without hemoglobin. The encapsulation efficiency and ferrous state of hemoglobin were analyzed, resulting in 60% encapsulation efficiency and a maximum of 20% ferric hemoglobin, yielding 100 µg/mL active hemoglobin in certain sfHBOC formulations. The system did not elicit a strong inflammation response in vitro, demonstrating the potential for this particle system to serve as an injectable HBOC.

Progress in silk and silk fiber-inspired polymeric nanomaterials for drug delivery.

The fields of drug and gene delivery have been revolutionized by the discovery and characterization of polymer-based materials. Polymeric nanomaterials have emerged as a strategy for targeted delivery because of features such as their impressive biocompatibility and improved availability. Use of naturally derived polymers in these nanomaterials is advantageous due to their biodegradability and bioresorption. Natural biopolymer-based particles composed of silk fibroins and other silk fiber-inspired proteins have been the focus of research in drug delivery systems due to their simple synthesis, tunable characteristics, and ability to respond to stimuli. Several silk and silk-inspired polymers contain a high proportion of reactive side groups, allowing for functionalization and addition of targeting moieties. In this review, we discuss the main classes of silk and silk-inspired polymers that are being used in the creation of nanomaterials. We also focus on the fabrication techniques used in generating a tunable design space of silk-based polymeric nanomaterials and detail how that translates into use for drug delivery to several distinct microenvironments.

Recent Advances in Natural Materials for Corneal Tissue Engineering.

Given the incidence of corneal dysfunctions and diseases worldwide and the limited availability of healthy, human donors, investigators are working to generate engineered cellular and acellular therapeutic approaches as alternatives to corneal transplants from human cadavers. These engineered strategies aim to address existing complications with human corneal transplants, including graft rejection, infection, and complications resulting from surgical methodologies. The main goals of these research endeavors are to (1) determine ideal mechanical properties, (2) devise methodologies to improve the efficacy of engineered corneal grafts and cell-based therapies, and (3) optimize transplantation of engineered tissue structures in the eye. Thus, recent innovations have sought to address these challenges through both in vitro and in vivo studies. This review covers recent work aimed at evaluating engineered materials, potential therapeutic cells, and the resulting cell-material interactions that lead to optimal corneal graft properties. Furthermore, we discuss promising strategies in corneal tissue engineering techniques and in vivo studies in animal models.

An evolution of risk assessment for potential carcinogens in food: Scientific session proceedings.

Modern perspectives on the risk assessment of carcinogenic potential of chemicals have taken shape within the last two decades. This has been due to both developments in the understanding of the biology and etiology of cancer and by advances in in silico and in vitro assays. Moving away from a conventional binary carcinogen/non-carcinogen model, modern frameworks offer more nuanced classification structures based on the understanding of mechanisms involved or potentially involved in rodent carcinogenicity. Given these developments, a scientific session at the 2020 Winter Meeting of the Toxicology Forum was organized to explore the impact these innovative approaches will have on food safety assessments and what considerations should be addressed in developing a new carcinogenic risk assessment approach for substances in foods. The session reviewed challenges faced by food toxicologists and risk assessors, current standard approaches for evaluating carcinogenic risk of food substances, limitations of these standard approaches, and potential methods to implement next generation assays and modern carcinogenic frameworks into food safety assessments. Current perspectives of US regulatory, industry, and academic stakeholders were represented during speaker presentations and a moderated Panel Discussion. This Workshop Report provides an overview of key themes and information presented during the session. Summary statements were prepared by the authors and reviewed by the presenters but do not necessarily represent the position or policy of the FDA, the EPA, or other affiliations.

Estimating Kinetic Rate Parameters for Enzymatic Degradation of Lyophilized Silk Fibroin Sponges.

Sponge-like biomaterials formed from silk fibroin are promising as degradable materials in clinical applications due to their controllable breakdown into simple amino acids or small peptides in vivo. Silk fibroin, isolated from Bombyx mori silkworm cocoons, can be used to form sponge-like materials with a variety of tunable parameters including the elastic modulus, porosity and pore size, and level of nanocrystalline domains. These parameters can be independently tuned during formulation resulting in a wide parameter space and set of final materials. Determining the mechanism and rate constants for biomaterial degradation of these tunable silk materials would allow scientists to evaluate and predict the biomaterial performance for the large array of tissue engineering applications and patient ailments a priori. We first measured in vitro degradation rates of silk sponges using common protein-degrading enzymes such as Proteinase K and Protease XIV. The concentration of the enzyme in solution was varied (1, 0.1, 0.01 U/mL) along with one silk sponge formulation parameter: the level of crystallinity within the sponge. Additionally, two experimental degradation methods were evaluated, termed continuous and discrete degradation methods. Silk concentration, polymer chain length and scaffold pore size were held constant during experimentation and kinetic parameter estimation. Experimentally, we observed that the enzyme itself, enzyme concentration within the bulk solution, and the sponge fabrication water annealing time were the major experimental parameters dictating silk sponge degradation in our experimental design. We fit the experimental data to two models, a Michaelis-Menten kinetic model and a modified first order kinetic model. Weighted, non-linear least squares analysis was used to determine the parameters from the data sets and Monte-Carlo simulations were utilized to obtain estimates of the error. We found that modified first order reaction kinetics fit the time-dependent degradation of lyophilized silk sponges and we obtained first order-like rate constants. These results represent the first investigations into determining kinetic parameters to predict lyophilized silk sponge degradation rates and can be a tool for future mathematical representations of silk biomaterial degradation.

Safety Assessment of Bacillus subtilis MB40 for Use in Foods and Dietary Supplements.

With the growing popularity of probiotics in dietary supplements, foods, and beverages, it is important to substantiate not only the health benefits and efficacy of unique strains but also safety. In the interest of consumer safety and product transparency, strain identification should include whole-genome sequencing and safety assessment should include genotypic and phenotypic studies. Bacillus subtilis MB40, a unique strain marketed for use in dietary supplements, and food and beverage, was assessed for safety and tolerability across in silico, in vitro, and in vivo studies. MB40 was assessed for the absence of undesirable genetic elements encoding toxins and mobile antibiotic resistance. Tolerability was assessed in both rats and healthy human volunteers. In silico and in vitro testing confirmed the absence of enterotoxin and mobile antibiotic resistance genes of safety concern to humans. In rats, the no-observed-adverse-effect level (NOAEL) for MB40 after repeated oral administration for 14 days was determined to be 2000 mg/kg bw/day (equivalent to 3.7 × 1011 CFU/kg bw/day). In a 28 day human tolerability trial, 10 × 109 CFU/day of MB40 was well tolerated. Based on genome sequencing, strain characterization, screening for undesirable attributes and evidence of safety by appropriately designed safety evaluation studies in rats and humans, Bacillus subtilis MB40 does not pose any human health concerns under the conditions tested.

Genetic Toxicity Studies of the Ketogenic Ester Bis Hexanoyl (R)-1,3-Butanediol.

A series of studies was conducted to assess the genetic toxicity of a novel ketone ester, bis hexanoyl (R)-1,3-butanediol (herein referred to as BH-BD), according to Organization for Economic Co-operation and Development testing guidelines under the standards of Good Laboratory Practices. In bacterial reverse mutation tests, there was no evidence of mutagenic activity in any of the Salmonella typhimurium strains tested or in Escherichia coli strain WP2uvrA, at dose levels up to 5,000 µg/plate in the presence or absence of Aroclor 1254-induced rat liver (S9 mix) for metabolic activation. In the in vitro micronucleus test using human TK6 cells, BH-BD did not show a statistically significant increase in the number of cells containing micronuclei when compared with concurrent control cultures at all time points and at any of the concentrations analyzed (up to 100 µg/mL, final concentration in culture medium), with and without S9 mix activation. In the in vivo micronucleus test using Sprague Dawley rats, BH-BD did not show a statistically significant increase in the incidence of micronucleated polychromatic erythrocytes relative to the vehicle control group. Therefore, BH-BD was concluded to be negative in all 3 tests. These results support the safety assessment of BH-BD for potential use in food.

Toxicological evaluation of the ketogenic ester bis hexanoyl (R)-1,3-butanediol: Subchronic toxicity in Sprague Dawley rats.

Bis-hexanoyl (R)-1,3-butanediol (BH-BD) is novel ketone ester undergoing development as a food ingredient to achieve nutritional ketosis in humans. Male and female Crl:CD(SD) rats were administered BH-BD twice daily at 9000, 12,000 or 15,000 mg/kg/day, by oral gavage in a 90-day toxicity study with 28-day recovery period; and an interim 28-day phase. Test substance-related early deaths occurred in four females at 15,000 mg/kg/day. A dose-dependent increase in acute transient postdose (1-3 h) observations of incoordination at ≥12,000 mg/kg/day and decreased activity at all dose levels were noted in both sexes. Postdose observations were likely associated with peak ketonemia and were considered adverse at 15,000 mg/kg/day. These daily observations decreased over the study without any persistent effects, as determined during weekly pre-dose observations. Adverse histopathological changes included ulceration/erosion in non-glandular stomach at ≥ 12,000 mg/k/day and in glandular stomach at 15,000 mg/kg/day. These histopathological findings were not noted after 28-days of recovery. Due to unlikely human relevance of the rat non-glandular stomach effects for BH-BD and test substance-related mortality at 15,000 mg/kg/day, the no-observed-adverse-effect level (NOAEL) for subchronic toxicity of BH-BD was determined to be 12,000 mg/kg/day.

Analytical and clinical performance of molecular assay used by the Brazilian public laboratory network to detect and discriminate Zika, Dengue and Chikungunya viruses in blood.

In response to the Zika epidemics in Brazil, the ZDC molecular assay (Bio-Manguinhos) was developed and registered at the Brazilian Regulatory Agency of Health Surveillance - ANVISA. The circulation of Zika (ZIKV) Dengue (DENV) and Chikungunya (CHIKV) viruses and their clinical similarities are challenges to correctly diagnose these viruses. The simultaneous detection of ZIKV, DENV and CHIKV is an important tool for diagnosis and surveillance. Here, we present the analytical and clinical performance evaluation of ZDC molecular assay (Bio-Manguinhos) at the public health laboratories three years after its registration at ANVISA. The clinical performance demonstrates the ZDC molecular assay (Bio-Manguinhos) has 100% sensitivity and 100% specificity to detect and discriminate ZIKV, CHIKV, and DENV from clinical plasma samples. The ZDC molecular assay (Bio-Manguinhos) results were highly reproducible and no cross-reactivity was seen during testing with a panel of other infectious agents. In conclusion, the ZDC molecular assay (Bio-Manguinhos) is an accurate and reliable tool to monitor Zika, dengue and chikungunya infections in countries like Brazil with simultaneous circulation of the three viruses.

In vitro stability and in vivo pharmacokinetics of the novel ketogenic ester, bis hexanoyl (R)-1,3-butanediol.

A novel ketone ester, bis hexanoyl (R)-1,3-butanediol (BH-BD), has been developed as a means to elevate blood ketones, for use as an energy substrate and a signaling metabolite. The metabolism of BH-BD and its effects on blood beta-hydroxybutyrate (BHB) levels was evaluated in various in vitro matrices and through analysis of plasma collected from Sprague Dawley rats and C57/BL6 mice in two oral gavage studies. A well-characterized ketone ester, (R)-3-hydroxybutyl (R)-3-hydroxybutyrate (HB-BHB), was used as an active control throughout. In vitro assay results demonstrated that BH-BD likely remains intact in the stomach and is hydrolyzed in the small intestine into hexanoate and (R)-1,3-butanediol. If absorbed intact, BH-BD is subject to hydrolysis by non-CYP enzymes in liver and esterases in plasma. If BH-BD reaches the lower intestine it is metabolized by gut flora. Plasma BHB delivery increased in a dose-dependent manner in rats and mice following oral administration of BH-BD. All doses of BH-BD were well tolerated. At doses over 3 g/kg, BHB delivery was similar between BH-BD and HB-BHB. The results of these studies support the hydrolysis of BH-BD into hexanoate and (R)-1,3-butanediol which are metabolized into BHB, delivering a well-tolerated, sustained and dose-dependent increase in plasma BHB in rodents.

Analytical and clinical performance of molecular assay used by the Brazilian public laboratory network to detect and discriminate Zika, Dengue and Chikungunya viruses in blood

ABSTRACT In response to the Zika epidemics in Brazil, the ZDC molecular assay (Bio-Manguinhos) was developed and registered at the Brazilian Regulatory Agency of Health Surveillance - ANVISA. The circulation of Zika (ZIKV) Dengue (DENV) and Chikungunya (CHIKV) viruses and their clinical similarities are challenges to correctly diagnose these viruses. The simultaneous detection of ZIKV, DENV and CHIKV is an important tool for diagnosis and surveillance. Here, we present the analytical and clinical performance evaluation of ZDC molecular assay (Bio-Manguinhos) at the public health laboratories three years after its registration at ANVISA. The clinical performance demonstrates the ZDC molecular assay (Bio-Manguinhos) has 100% sensitivity and 100% specificity to detect and discriminate ZIKV, CHIKV, and DENV from clinical plasma samples. The ZDC molecular assay (Bio-Manguinhos) results were highly reproducible and no cross-reactivity was seen during testing with a panel of other infectious agents. In conclusion, the ZDC molecular assay (Bio-Manguinhos) is an accurate and reliable tool to monitor Zika, dengue and chikungunya infections in countries like Brazil with simultaneous circulation of the three viruses.

Examining cognitive control and reward interactions in adolescent externalizing symptoms.

During adolescence, rapid development and reorganization of the dopaminergic system supports increasingly sophisticated reward learning and the ability to exert behavioral control. Disruptions in the ability to exert control over previously rewarded behavior may underlie some forms of adolescent psychopathology. Specifically, symptoms of externalizing psychopathology may be associated with difficulties in flexibly adapting behavior in the context of reward. However, the direct interaction of cognitive control and reward learning in adolescent psychopathology symptoms has not yet been investigated. The present study used a Research Domain Criteria framework to investigate whether behavioral and neuronal indices of inhibition to previously rewarded stimuli underlie individual differences in externalizing symptoms in N = 61 typically developing adolescents. Using a task that integrates the Monetary Incentive Delay and Go-No-Go paradigms, we observed a positive association between externalizing symptoms and activation of the left middle frontal gyrus during response inhibition to cues with a history of reward. These associations were robust to controls for internalizing symptoms and neural recruitment during inhibition of cues with no reward history. Our findings suggest that inhibitory control over stimuli with a history of reward may be a useful marker for future inquiry into the development of externalizing psychopathology in adolescence.

A weight of evidence assessment of the genotoxic potential of 4-methylimidazole as a possible mode of action for the formation of lung tumors in exposed mice.

4-Methylimidazole (4-MeI) is a byproduct formed during the cooking of foods containing carbohydrates and amino acids, including the production of flavors and coloring substances, e.g., class III and IV caramel colors, used in many food products with extensive human exposure. Two-year rodent bioassays via oral exposure conducted by the National Toxicology Program reported evidence of carcinogenicity only in B6C3F1 mice (increased alveolar/bronchial neoplasms). In 2011, the International Agency for Research on Cancer classified 4-MeI as Group 2B, "possibly carcinogenic to humans". An expert panel was commissioned to assess the genotoxic potential of 4-MeI and the plausibility of a genotoxic mode of action in the formation of lung tumors in mice when exposed to high doses of 4-MeI. The panel defined and used a weight-of-evidence (WOE) approach that included thorough evaluation of studies assessing the genotoxic potential of 4-MeI. The panelists categorized each study, consisting of study weight, degree of technical performance, study reliability, and contribution to the overall WOE. Based on the reviewed studies' weighted contribution, the panel unanimously concluded that the WOE supports no clear evidence of in vivo genotoxicity of 4-MeI and no association for a genotoxic mode of action in the formation of mouse lung tumors.

Biomass addition alters community assembly in ultrafiltration membrane biofilms.

Freshwater biofilms assemble from a pool of rare water column genotypes. Random density fluctuations and temporal species turnover of functionally equivalent potential colonizers result in compositional variability of newly formed biofilm communities. We hypothesized that stronger environmental filtering as induced by enhanced substrate levels might reduce the impact of a locally variable pool of colonizers and instead select for more universal habitat specialists. Our model were heterotrophic biofilms that form on membranes during gravity-driven ultrafiltration of lake water. In four separate experiments, biomass of the cyanobacterium Microcystis was added to the feed water of one set of treatments (BM) and the resulting biofilm communities were compared to unamended controls (CTRL). Biomass addition led to a significant shift of community assembly processes: Replicate BM biofilms were more similar to each other than by chance in 3 of 4 experiments, whereas the opposite was the case for CTRL communities. Moreover, BM communities were more stochastically assembled across experiments from a common 'regional' pool of biofilm colonizers, whereas the composition of CTRL communities was mainly determined by experiment-specific 'local' genotypes. Interestingly, community assembly processes were also related to both, physiology (aerobic vs. anaerobic lifestyle) and the phylogenetic affiliation of biofilm bacteria.

Functional Alterations Associated with Structural Abnormalities in Adults with High-Functioning Autism Spectrum Disorder.

Background: The combination of structural and functional analyses is a biologically valid approach that offers methodological advantages in autism spectrum disorder (ASD) neuroimaging science. The paucity of studies combining these methods constitutes an important knowledge gap. In this study, we investigate structural abnormalities and their associated functional differences in a developmentally homogeneous ASD cohort. Methods: Whole-brain voxel-based morphometry (VBM) analyses were performed on 28 ASD participants and 38 age-matched typically developing healthy controls (HC) to derive gray matter (GM) volume differences. The anatomically relevant clusters identified by VBM served as seed regions of interest (ROI) for resting-state functional-connectivity (RsFc) analysis. Results: Whole-brain VBM analyses revealed significant right lateralized GM volume abnormality in the ASD group, with lower GM volumes in cerebellar lobules VIIb/VIIIa (cluster 1) and significantly higher GM volumes in posterior middle/superior temporal gyri (Brodmann area [BA] 21/22, cluster 2) compared with HC. Whole-brain RsFc analysis in high-functioning ASD (HF-ASD) revealed significant hypoconnectivity of the cerebellar VBM cluster with the right cerebral cortical regions of superior parietal lobule (BA 7) and occipital pole (BA 19) (overlapping with dorsal attention and visual networks, respectively). Cerebral cortical VBM cluster (cluster 2) revealed significant hypoconnectivity in HF-ASD with other task-positive cerebral cortical including the left lateral prefrontal cortex (frontoparietal network) and some aspects of the insula (ventral attention network) and ectopic positive connectivity (lack of anticorrelations) with posterior cingulate cortex and medial prefrontal cortex (default mode network). Conclusions: The cerebro-cerebellar intrinsic functional dysconnectivity based on the whole-brain VBM-derived ROIs may advance our understanding of the compensatory mechanisms associated with ASD and offer cerebellum as a potential target for diagnostic, predictive, prognostic, and therapeutic interventions in ASD. Our findings also provide additional support indicating that functional abnormalities as indexed by RsFc exist in ASD, and highlight that there is likely a relationship between structural and functional abnormalities in this disorder. Impact statement Our findings indicate that functional differences as indexed by resting-state functional connectivity exist in autism spectrum disorder (ASD), and highlight that there is likely a relationship between structural and functional abnormalities in this disorder. Future developments in neuroimaging research should continue investigating structural and associated functional differences in ASD, and in this way complement the behavioral characterization of this disorder, potentially improving diagnosis, prognosis, and prediction.

The Fully human anti-CD47 antibody SRF231 exerts dual-mechanism antitumor activity via engagement of the activating receptor CD32a.

BACKGROUND: CD47 is a broadly expressed cell surface glycoprotein associated with immune evasion. Interaction with the inhibitory receptor signal regulatory protein alpha (SIRPα), primarily expressed on myeloid cells, normally serves to restrict effector function (eg, phagocytosis and immune cell homeostasis). CD47/SIRPα antagonists, commonly referred to as 'macrophage checkpoint' inhibitors, are being developed as cancer interventions. SRF231 is an investigational fully human IgG4 anti-CD47 antibody that is currently under evaluation in a phase 1 clinical trial. The development and preclinical characterization of SRF231 are reported here. METHODS: SRF231 was characterized in assays designed to probe CD47/SIRPα blocking potential and effects on red blood cell (RBC) phagocytosis and agglutination. Additionally, SRF231-mediated phagocytosis and cell death were assessed in macrophage:tumor cell in vitro coculture systems. Further mechanistic studies were conducted within these coculture systems to ascertain the dependency of SRF231-mediated antitumor activity on Fc receptor engagement vs CD47/SIRPα blockade. In vivo, SRF231 was evaluated in a variety of hematologic xenograft models, and the mechanism of antitumor activity was assessed using cytokine and macrophage infiltration analyses following SRF231 treatment. RESULTS: SRF231 binds CD47 and disrupts the CD47/SIRPα interaction without causing hemagglutination or RBC phagocytosis. SRF231 exerts antitumor activity in vitro through both phagocytosis and cell death in a manner dependent on the activating Fc-gamma receptor (FcγR), CD32a. Through its Fc domain, SRF231 engagement with macrophage-derived CD32a serves dual purposes by eliciting FcγR-mediated phagocytosis of cancer cells and acting as a scaffold to drive CD47-mediated death signaling into tumor cells. Robust antitumor activity occurs across multiple hematologic xenograft models either as a single agent or in combination with rituximab. In tumor-bearing mice, SRF231 increases tumor macrophage infiltration and induction of the macrophage cytokines, mouse chemoattractant protein 1 and macrophage inflammatory protein 1 alpha. Macrophage depletion results in diminished SRF231 antitumor activity, underscoring a mechanistic role for macrophage engagement by SRF231. CONCLUSION: SRF231 elicits antitumor activity via apoptosis and phagocytosis involving macrophage engagement in a manner dependent on the FcγR, CD32a.

Priming of microcystin degradation in carbon-amended membrane biofilm communities is promoted by oxygen-limited conditions.

Microbial biofilms are an important element of gravity-driven membrane (GDM) filtration systems for decentralized drinking water production. Mature biofilms fed with biomass from the toxic cyanobacterium Microcystis aeruginosa efficiently remove the cyanotoxin microcystin (MC). MC degradation can be 'primed' by prior addition of biomass from a non-toxic M. aeruginosa strain. Increased proportions of bacteria with an anaerobic metabolism in M. aeruginosa-fed biofilms suggest that this 'priming' could be due to higher productivity and the resulting changes in habitat conditions. We, therefore, investigated GDM systems amended with the biomass of toxic (WT) or non-toxic (MUT) M. aeruginosa strains, of diatoms (DT), or with starch solution (ST). After 25 days, these treatments were changed to receiving toxic cyanobacterial biomass. MC degradation established significantly more rapidly in MUT and ST than in DT. Oxygen measurements suggested that this was due to oxygen-limited conditions in MUT and ST already prevailing before addition of MC-containing biomass. Moreover, the microbial communities in the initial ST biofilms featured high proportions of facultative anaerobic taxa, whereas aerobes dominated in DT biofilms. Thus, the 'priming' of MC degradation in mature GDM biofilms seems to be related to the prior establishment of oxygen-limited conditions mediated by higher productivity.

Within-winter flexibility in muscle and heart lipid transport and catabolism in passerine birds.

Small birds in cold climates may show within-winter metabolic flexibility to match metabolic capacities to prevailing weather conditions. This flexibility may occur over periods of days to weeks, but the underlying mechanisms for such flexibility are not well understood. Because lipids are the primary fuel for sustained thermogenesis, we examined whether lipid transport and catabolism can mediate within-winter metabolic flexibility in two small temperate-zone wintering passerine birds, dark-eyed juncos (Junco hyemalis) and house sparrows (Passer domesticus). We used simple and multiple regression analyses to test for correlations of several lipid transporters in pectoralis muscle (plasma membrane-bound and cytosolic fatty acid-binding proteins, FABP; fatty acyl translocase, FAT/CD36) and regulatory enzymes (carnitine acyl transferase, CPT; ß-hydroxyacyl CoA dehydrogenase, HOAD) in pectoralis and heart with short-term (ST, 0-7 days), medium-term (MT, 14-30 days) and long-term (LT, 30-year mean daily and extreme minimum temperatures, day of winter season) temperature variables. We hypothesized negative correlations between these regulators and temperature variables. Juncos showed negative correlations for FABPs with ST or MT temperature variables, but other lipid transporters and regulatory enzymes showed positive correlations with ST or MT temperatures for juncos, suggesting no consistent pathway-wide response to within-winter temperatures. LT temperature variables showed several significant associations with lipid transporters and enzymes for juncos, but also not in consistent directions. House sparrows showed the expected negative correlations with LT temperatures for FABPpm, but positive correlations with temperature variables for FABPc, CPT and HOAD. Different species-specific patterns of variation and the absence of consistent pathway-wide responses to temperature suggest that the lipid transport and catabolism pathway is not a uniform mediator of within-winter metabolic flexibility among small birds.