Digital platforms to facilitate physical activities for people with physical or sensory disabilities: A scoping review.

BACKGROUND: People with disabilities (PWD) commonly experience difficulties in accessing their environments, which can lead to restricted participation in outdoor leisure-time physical activity. Participating in outdoor leisure-time physical activity (OLTPA) provides health and social benefits to PWD and benefits to the communities in which they live. OBJECTIVE: The aim of the study was to identify features existing in digital platforms that facilitate access to OLTPA for PWD. METHODS: A scoping review was conducted in four library databases and in Google advance search to identify relevant scientific and grey literature, and websites. Each step of the review was independently conducted by two co-authors who confirmed consensus of results. Descriptive data analyses were performed. RESULTS: Seven scientific studies and ten websites were included in the scoping review. Seven presented mobile apps, nine presented a website and one presented an online database. Sources reported five main obstacles to using digital platforms that support access to physical activities (e.g., lack of digital literacy, technical issues, unintuitive design), and 10 facilitators (e.g., possibility to personalize your online space, accessibility features of the navigation). Among these sources, a trend emerged in the most important factors and features to consider for the visuals and navigation of the platforms. CONCLUSION: The features of digital platforms that facilitate access to OLTPA include intuitive design compliant with accessibility guidelines and supported by navigation tools, personalization of the online space, and features for social interactions.

In-plasma analysis of plasma-surface interactions.

During deposition, modification, and etching of thin films and nanomaterials in reactive plasmas, many active species can interact with the sample simultaneously. This includes reactive neutrals formed by fragmentation of the feed gas, positive ions, and electrons generated by electron-impact ionization of the feed gas and fragments, excited states (in particular, long-lived metastable species), and photons produced by spontaneous de-excitation of excited atoms and molecules. Notably, some of these species can be transiently present during the different phases of plasma processing, such as etching of thin layer deposition. To monitor plasma-surface interactions during materials processing, a new system combining beams of neutral atoms, positive ions, UV photons, and a magnetron plasma source has been developed. This system is equipped with a unique ensemble of in-plasma surface characterization tools, including (1) a Rutherford Backscattering Spectrometer (RBS), (2) an Elastic Recoil Detector (ERD), and (3) a Raman spectroscopy system. RBS and ERD analyses are carried out using a differentially pumped 1.7 MV ion beam line Tandetron accelerator generating a beam at grazing incidence. The ERD system is equipped with an absorber and is specifically used to detect H initially bonded to the surface; higher resolution of surface H is also available through nuclear reaction analysis. In parallel, an optical port facing the substrate is used to perform Raman spectroscopy analysis of the samples during plasma processing. This system enables fast monitoring of a few Raman peaks over nine points scattered on a 1.6 × 1.6 mm2 surface without interference from the inherent light emitted by the plasma. Coupled to the various plasma and beam sources, the unique set of in-plasma surface characterization tools detailed in this study can provide unique time-resolved information on the modification induced by plasma. By using the ion beam analysis capability, the atomic concentrations of various elements in the near-surface (e.g., stoichiometry and impurity content) can be monitored in real-time during plasma deposition or etching. On the other hand, the evolution of Raman peaks as a function of plasma processing time can contribute to a better understanding of the role of low-energy ions in defect generation in irradiation-sensitive materials, such as monolayer graphene.

Strategies aimed at preventing long-term opioid use in trauma and orthopaedic surgery: a scoping review.

BACKGROUND: Long-term opioid use, which may have significant individual and societal impacts, has been documented in up to 20% of patients after trauma or orthopaedic surgery. The objectives of this scoping review were to systematically map the research on strategies aiming to prevent chronic opioid use in these populations and to identify knowledge gaps in this area. METHODS: This scoping review is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Checklist. We searched seven databases and websites of relevant organizations. Selected studies and guidelines were published between January 2008 and September 2021. Preventive strategies were categorized as: system-based, pharmacological, educational, multimodal, and others. We summarized findings using measures of central tendency and frequency along with p-values. We also reported the level of evidence and the strength of recommendations presented in clinical guidelines. RESULTS: A total of 391 studies met the inclusion criteria after initial screening from which 66 studies and 20 guidelines were selected. Studies mainly focused on orthopaedic surgery (62,1%), trauma (30.3%) and spine surgery (7.6%). Among system-based strategies, hospital-based individualized opioid tapering protocols, and regulation initiatives limiting the prescription of opioids were associated with statistically significant decreases in morphine equivalent doses (MEDs) at 1 to 3 months following trauma and orthopaedic surgery. Among pharmacological strategies, only the use of non-steroidal anti-inflammatory drugs and beta blockers led to a significant reduction in MEDs up to 12 months after orthopaedic surgery. Most studies on educational strategies, multimodal strategies and psychological strategies were associated with significant reductions in MEDs beyond 1 month. The majority of recommendations from clinical practice guidelines were of low level of evidence. CONCLUSIONS: This scoping review advances knowledge on existing strategies to prevent long-term opioid use in trauma and orthopaedic surgery patients. We observed that system-based, educational, multimodal and psychological strategies are the most promising. Future research should focus on determining which strategies should be implemented particularly in trauma patients at high risk for long-term use, testing those that can promote a judicious prescription of opioids while preventing an illicit use, and evaluating their effects on relevant patient-reported and social outcomes.

Correction: Two stable variants of Burkholderia pseudomallei strain MSHR5848 express broadly divergent in vitro phenotypes associated with their virulence differences.

[This corrects the article DOI: 10.1371/journal.pone.0171363.].

Soy Isoflavone Supplementation Increases Long Interspersed Nucleotide Element-1 (LINE-1) Methylation in Head and Neck Squamous Cell Carcinoma.

AIM: Soy isoflavones have been suggested as epigenetic modulating agents with effects that could be important in carcinogenesis. Hypomethylation of LINE-1 has been associated with head and neck squamous cell carcinoma (HNSCC) development from oral premalignant lesions and with poor prognosis. To determine if neoadjuvant soy isoflavone supplementation could modulate LINE-1 methylation in HNSCC, we undertook a clinical trial. METHODS: Thirty-nine patients received 2-3 weeks of soy isoflavone supplements (300 mg/day) orally prior to surgery. Methylation of LINE-1, and 6 other genes was measured by pyrosequencing in biopsy, resection, and whole blood (WB) specimens. Changes in methylation were tested using paired t tests and ANOVA. Median follow up was 45 months. RESULTS: LINE-1 methylation increased significantly after soy isoflavone (P < 0.005). Amount of change correlated positively with days of isoflavone taken (P = 0.04). Similar changes were not seen in corresponding WB samples. No significant changes in tumor or blood methylation levels were seen in the other candidate genes. CONCLUSION: This is the first demonstration of in vivo increases in tissue-specific global methylation associated with soy isoflavone intake in patients with HNSCC. Prior associations of LINE-1 hypomethylation with genetic instability, carcinogenesis, and prognosis suggest that soy isoflavones maybe potential chemopreventive agents in HNSCC.

Production of recycled manure solids for use as bedding in Canadian dairy farms: II. Composting methods.

Recent technological advances in the dairy industry have enabled Canadian farms with liquid manure systems to use mechanical solid-liquid separation paired with composting of the separated solids for on-farm production of low-cost bedding material. However, because several approaches are available, it is difficult for farmers to select the appropriate one to achieve high quality recycled manure solids (RMS). Whereas 3 solid-liquid manure separators were compared in part I of the series (companion paper in this issue), the present study (part II) aims to assess the performance of 4 composting methods (static or turned windrow and drum composter for 24 or 72 h) under laboratory conditions. Parameters evaluated included temperature, physico-chemical characteristics, and bacterial composition of RMS, as well as airborne microorganisms, dust, and gases associated with composting RMS. Because each treatment attained the desired composting temperature range of 40 to 65°C (either in heaps or in the drum composter), reductions in bacteria were a better indicator of the sanitation efficiency. The treatment of fresh RMS in a drum composter for 24 h showed decreased bacterial counts, especially for Escherichia coli (from 1.0 × 105 to 2.0 × 101 cfu/g of dry matter) and Klebsiella spp. (from 3.2 × 104 to 4.0 × 102 cfu/g of dry matter). Increasing the time spent in the rotating vessel to 72 h did not result in further decreases of these pathogens. Composting in a static or turned windrow achieved similar E. coli and Klebsiella spp. reductions as the 24-h drum composting but in 5 or 10 d, and generally showed the lowest occupational exposure risk for dairy farmers regarding concentrations of airborne mesophilic bacteria, mesophilic and thermotolerant fungi, and total dust. Drum-composted RMS stored in piles exhibited intermediate to high risk. Composting approaches did not have a major influence on the physico-chemical characteristics of RMS and gas emissions. Drum composting for 24 h was the best compromise in terms of product quality, temperature reached, decreased bacterial numbers, and emitted airborne contaminants. However, because levels of pathogenic agents rapidly increase once composted RMS are spread in stalls, bacteriological characteristics of RMS along with milk quality and animal health and welfare features should be monitored in Canadian dairy barns applying recommended separation (part I) and composting (part II) systems to evaluate health risk and optimize management practices.

Production of recycled manure solids for bedding in Canadian dairy farms: I. Solid-liquid separation.

Canadian dairy producers have an increasing interest in recycled manure solids (RMS) as bedding material because of reduced availability of traditional bedding resources. Information regarding methods to obtain RMS and composition of RMS is very limited. Hence, a 2-part investigation was developed to compare the performances of 3 mechanical solid-liquid manure separators (part I) and 4 composting methods (part II; companion paper in this issue) for the production of high quality RMS. In this first study, a roller press, a screw press, and a decanter centrifuge were tested for the separation of slurry manure from a commercial dairy farm. During the experiment, the quantity of slurry manure processed and the volume and mass of the liquid and solid fractions were measured. The energy consumption of each separator was recorded, and samples of the slurry, liquid, and solid effluents were collected for analysis. The type of separator did not significantly influence the chemical and bacteriological composition of RMS produced. The choice of a separator for Canadian dairy producers should thus be based on the equipment cost and its capacity, targeted solids dry matter (DM) content and structure, and fertilizing quality of the separated liquid. The decanter centrifuge produced the solid phase with the highest DM and best separation efficiencies for DM, N, and P. However, its low production capacity (1.5 m3/h vs. 9.1-20.3 m3/h) combined with its high acquisition cost (Can$145,000 vs. Can$75,000) and energy consumption (4.99 kWh/m3 vs. 0.10-0.35 kWh/m3) reduce its technical and profitability values. Besides, the centrifuge produced fine structured RMS and a low-quality liquid fraction, not suitable as dairy cow bedding and fertilizer, respectively. Both presses reached acceptable production capacity at a minimal operation cost. However, the poor performance in terms of DM (25%) of the model of screw press used in this study produced RMS unsuitable for immediate use without further processing. The model of roller press used in this study had the advantages of almost reaching the recommended DM content in RMS (>34%), being flexible in terms of inputs, and producing fluffy RMS. Nevertheless, its compression process seemed to allow greater passage of solids into the liquid fraction compared with the screw press. Part II of this work explores different composting methods to reduce the health risks associated with screw-pressed RMS before their use as bedding.

Incorporating germination-induction into decontamination strategies for bacterial spores.

Bacterial spores resist environmental extremes and protect key spore macromolecules until more supportive conditions arise. Spores germinate upon sensing specific molecules, such as nutrients. Germination is regulated by specialized mechanisms or structural features of the spore that limit contact with germinants and enzymes that regulate germination. Importantly, germination renders spores more susceptible to inactivating processes such as heat, desiccation, and ultraviolet radiation, to which they are normally refractory. Thus, germination can be intentionally induced through a process called germination-induction and subsequent treatment of these germinated spores with common disinfectants or gentle heat will inactivate them. However, while the principle of germination-induction has been shown effective in the laboratory, this strategy has not yet been fully implemented in real-word scenarios. Here, we briefly review the mechanisms of bacterial spore germination and discuss the evolution of germination-induction as a decontamination strategy. Finally, we examine progress towards implementing germination-induction in three contexts: biodefense, hospital settings and food manufacture. SIGNIFICANCE AND IMPACT: This article reviews implementation of germination-induction as part of a decontamination strategy for the cleanup of bacterial spores. To our knowledge this is the first time that germination-induction studies have been reviewed in this context. This article will provide a resource which summarizes the mechanisms of germination in Clostridia and Bacillus species, challenges and successes in germination-induction, and potential areas where this strategy may be implemented.

Comparison of sampling methods to recover germinated Bacillus anthracis and Bacillus thuringiensis endospores from surface coupons.

AIMS: In an attempt to devise decontamination methods that are both effective and minimally detrimental to the environment, we evaluated germination induction as an enhancement to strategies for Bacillus anthracis spore decontamination. To determine an optimal method for the recovery of germinating spores from different matrices, it was critical to ensure that the sampling procedures did not negatively impact the viability of the germinating spores possibly confounding the results and downstream analyses of field trial data. METHODS AND RESULTS: Therefore, the two main objectives of this study were the following: (i) development of an effective processing protocol capable of recovering the maximum number of viable germinating or germinated spores from different surface materials; and (ii) using a model system of spore contamination, employ this protocol to evaluate the potential applicability of germination induction to wide-area decontamination of B. anthracis spores. We examined parameters affecting the sampling efficiencies of B. anthracis and the surrogate species Bacillus thuringiensis on nonporous and porous materials. CONCLUSIONS: The most efficient extraction from all matrices was observed using PBS with 0·01% Tween 80 extraction buffer. The addition of a sonication and/or extended vortex treatment did not yield significant increases in spore or germinated spore recovery. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data demonstrate that previous germination-induction experiments performed in suspension can be reproduced when Bacillus spores are deposited onto reference surfaces materials. Our proof of concept experiment illustrated that a germination pretreatment step significantly improves conventional secondary decontamination strategies and remediation plans.

Two stable variants of Burkholderia pseudomallei strain MSHR5848 express broadly divergent in vitro phenotypes associated with their virulence differences.

Burkholderia pseudomallei (Bp), the agent of melioidosis, causes disease ranging from acute and rapidly fatal to protracted and chronic. Bp is highly infectious by aerosol, can cause severe disease with nonspecific symptoms, and is naturally resistant to multiple antibiotics. However, no vaccine exists. Unlike many Bp strains, which exhibit random variability in traits such as colony morphology, Bp strain MSHR5848 exhibited two distinct and relatively stable colony morphologies on sheep blood agar plates: a smooth, glossy, pale yellow colony and a flat, rough, white colony. Passage of the two variants, designated "Smooth" and "Rough", under standard laboratory conditions produced cultures composed of > 99.9% of the single corresponding type; however, both could switch to the other type at different frequencies when incubated in certain nutritionally stringent or stressful growth conditions. These MSHR5848 derivatives were extensively characterized to identify variant-associated differences. Microscopic and colony morphology differences on six differential media were observed and only the Rough variant metabolized sugars in selective agar. Antimicrobial susceptibilities and lipopolysaccharide (LPS) features were characterized and phenotype microarray profiles revealed distinct metabolic and susceptibility disparities between the variants. Results using the phenotype microarray system narrowed the 1,920 substrates to a subset which differentiated the two variants. Smooth grew more rapidly in vitro than Rough, yet the latter exhibited a nearly 10-fold lower lethal dose for mice than Smooth. Finally, the Smooth variant was phagocytosed and replicated to a greater extent and was more cytotoxic than Rough in macrophages. In contrast, multiple locus sequence type (MLST) analysis, ribotyping, and whole genome sequence analysis demonstrated the variants' genetic conservation; only a single consistent genetic difference between the two was identified for further study. These distinct differences shown by two variants of a Bp strain will be leveraged to better understand the mechanism of Bp phenotypic variability and to possibly identify in vitro markers of infection.

Characterization of in vitro phenotypes of Burkholderia pseudomallei and Burkholderia mallei strains potentially associated with persistent infection in mice.

Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm), the agents of melioidosis and glanders, respectively, are Tier 1 biothreats. They infect humans and animals, causing disease ranging from acute and fatal to protracted and chronic. Chronic infections are especially challenging to treat, and the identification of in vitro phenotypic markers which signal progression from acute to persistent infection would be extremely valuable. First, a phenotyping strategy was developed employing colony morphotyping, chemical sensitivity testing, macrophage infection, and lipopolysaccharide fingerprint analyses to distinguish Burkholderia strains. Then mouse spleen isolates collected 3-180 days after infection were characterized phenotypically. Isolates from long-term infections often exhibited increased colony morphology differences and altered patterns of antimicrobial sensitivity and macrophage infection. Some of the Bp and Bm persistent infection isolates clearly displayed enhanced virulence in mice. Future studies will evaluate the potential role and significance of these phenotypic markers in signaling the establishment of a chronic infection.

Intense THz Pulses with large ponderomotive potential generated from large aperture photoconductive antennas.

We report the generation of free space terahertz (THz) pulses with energy up to 8.3 ± 0.2 µJ from an encapsulated interdigitated ZnSe Large Aperture Photo-Conductive Antenna (LAPCA). An aperture of 12.2 cm2 is illuminated using a 400 nm pump laser with multi-mJ energies at 10 Hz repetition rate. The calculated THz peak electric field is 331 ± 4 kV/cm with a spectrum characterized by a median frequency of 0.28 THz. Given its relatively low frequency, this THz field will accelerate charged particles efficiently having very large ponderomotive energy of 15 ± 1 eV for electrons in vacuum. The scaling of the emission is studied with respect to the dimensions of the antenna, and it is observed that the capacitance of the LAPCA leads to a severe decrease in and distortion of the biasing voltage pulse, fundamentally limiting the maximum applied bias field and consequently the maximum energy of the radiated THz pulses. In order to demonstrate the advantages of this source in the strong field regime, an open-aperture Z-scan experiment was performed on n-doped InGaAs, which showed significant absorption bleaching.

Proteogenomic-based discovery of minor histocompatibility antigens with suitable features for immunotherapy of hematologic cancers.

Pre-clinical studies have shown that injection of allogeneic T cells primed against a single minor histocompatibility antigen (MiHA) could cure hematologic cancers (HC) without causing any toxicity to the host. However, translation of this approach in humans has been hampered by the paucity of molecularly defined human MiHAs. Using a novel proteogenomic approach, we have analyzed cells from 13 volunteers and discovered a vast repertoire of MiHAs presented by the most common HLA haplotype in European Americans: HLA-A*02:01;B*44:03. Notably, out of >6000 MiHAs, we have identified a set of 39 MiHAs that share optimal features for immunotherapy of HCs. These 'optimal MiHAs' are coded by common alleles of genes that are preferentially expressed in hematopoietic cells. Bioinformatic modeling based on MiHA allelic frequencies showed that the 39 optimal MiHAs would enable MiHA-targeted immunotherapy of practically all HLA-A*02:01;B*44:03 patients. Further extension of this strategy to a few additional HLA haplotypes would allow treatment of almost all patients.

The impact of inducing germination of Bacillus anthracis and Bacillus thuringiensis spores on potential secondary decontamination strategies.

AIMS: Decontamination and remediation of a site contaminated by the accidental or intentional release of fully virulent Bacillus anthracis spores are difficult, costly and potentially damaging to the environment. Development of novel decontamination strategies that have minimal environmental impacts remains a high priority. Although ungerminated spores are amongst the most resilient organisms known, once exposed to germinants, the germinating spores, in some cases, become susceptible to antimicrobial environments. We evaluated the concept that once germinated, B. anthracis spores would be less hazardous and significantly easier to remediate than ungerminated dormant spores. METHODS AND RESULTS: Through in vitro germination and sensitivity assays, we demonstrated that upon germination, B. anthracis Ames spores and Bacillus thuringiensis Al Hakam spores (serving as a surrogate for B. anthracis) become susceptible to environmental stressors. The majority of these germinated B. anthracis and B. thuringiensis spores were nonviable after exposure to a defined minimal germination-inducing solution for prolonged periods of time. Additionally, we examined the impact of potential secondary disinfectant strategies including bleach, hydrogen peroxide, formaldehyde and artificial UV-A, UV-B and UV-C radiation, employed after a 60-min germination-induction step. Each secondary disinfectant employs a unique mechanism of killing; as a result, germination-induction strategies are better suited for some secondary disinfectants than others. CONCLUSIONS: These results provide evidence that the deployment of an optimal combination strategy of germination-induction/secondary disinfection may be a promising aspect of wide-area decontamination following a B. anthracis contamination event. SIGNIFICANCE AND IMPACT OF THE STUDY: By inducing spores to germinate, our data confirm that the resulting cells exhibit sensitivities that can be leveraged when paired with certain decontamination measures. This increased susceptibility could be exploited to devise more efficient and safe decontamination measures and may obviate the need for more stringent methods that are currently in place.

D-cycloserine or similar physiochemical compounds may be uniquely suited for use in Bacillus anthracis spore decontamination strategies.

AIMS: As observed in the aftermath of the anthrax attacks of 2001, decontamination and remediation of a site contaminated by the accidental or intentional release of Bacillus anthracis spores is difficult, costly and potentially damaging to the environment. The identification of novel strategies that neutralize the threat of spores while minimizing environmental damage remains a high priority. We investigated the efficacy of d-cycloserine (DCS), an antibiotic and inhibitor of the spore-associated enzyme (alanine racemase) responsible for converting l-alanine to d-alanine, as a spore germination enhancer and antimicrobial agent. METHODS AND RESULTS: We characterized the impact of DCS exposure on both germinating spores and vegetative cells of fully virulent B. anthracis by evaluating spore germination kinetics, determining the minimum inhibitory concentrations (MICs) required to affect growth of the bacteria and performing macrophage viability assays. DCS enhanced germination induced by l-alanine and also efficiently killed the newly germinated spores. Furthermore, DCS proved nontoxic to macrophages at concentrations that provided protection from the killing effects of spores. Similar tests were conducted with Bacillus thuringiensis (subspecies kurstaki and Al Hakam) to determine its potential as a possible surrogate for B. anthracis field trials. Bacillus thuringiensis spores responded in a similar manner to B. anthracis spores when exposed to DCS. CONCLUSIONS: These results further support that DCS augments the germination response of spores in the presence of l-alanine but also reveal that DCS is bactericidal towards germinating spores. SIGNIFICANCE AND IMPACT OF THE STUDY: DCS (or similar compounds) may be uniquely suited for use as part of decontamination strategies by augmenting the induction of spore germination and then rendering the germinated spores nonviable.

Characterization of a multi-component anthrax vaccine designed to target the initial stages of infection as well as toxaemia.

Current vaccine approaches to combat anthrax are effective; however, they target only a single protein [the protective antigen (PA) toxin component] that is produced after spore germination. PA production is subsequently increased during later vegetative cell proliferation. Accordingly, several aspects of the vaccine strategy could be improved. The inclusion of spore-specific antigens with PA could potentially induce protection to initial stages of the disease. Moreover, adding other epitopes to the current vaccine strategy will decrease the likelihood of encountering a strain of Bacillus anthracis (emerging or engineered) that is refractory to the vaccine. Adding recombinant spore-surface antigens (e.g. BclA, ExsFA/BxpB and p5303) to PA has been shown to augment protection afforded by the latter using a challenge model employing immunosuppressed mice challenged with spores derived from the attenuated Sterne strain of B. anthracis. This report demonstrated similar augmentation utilizing guinea pigs or mice challenged with spores of the fully virulent Ames strain or a non-toxigenic but encapsulated ΔAmes strain of B. anthracis, respectively. Additionally, it was shown that immune interference did not occur if optimal amounts of antigen were administered. By administering the toxin and spore-based immunogens simultaneously, a significant adjuvant effect was also observed in some cases. Thus, these data further support the inclusion of recombinant spore antigens in next-generation anthrax vaccine strategies.

Humanized theta-defensins (retrocyclins) enhance macrophage performance and protect mice from experimental anthrax infections.

Retrocyclins are humanized versions of the -defensin peptides expressed by the leukocytes of several nonhuman primates. Previous studies, performed in serum-free media, determined that retrocyclins 1 (RC1) and RC2 could prevent successful germination of Bacillus anthracis spores, kill vegetative B. anthracis cells, and inactivate anthrax lethal factor. We now report that retrocyclins are extensively bound by components of native mouse, human, and fetal calf sera, that heat-inactivated sera show greatly enhanced retrocyclin binding, and that native and (especially) heat-inactivated sera greatly reduce the direct activities of retrocyclins against spores and vegetative cells of B. anthracis. Nevertheless, we also found that retrocyclins protected mice challenged in vivo by subcutaneous, intraperitoneal, or intranasal instillation of B. anthracis spores. Retrocyclin 1 bound extensively to B. anthracis spores and enhanced their phagocytosis and killing by murine RAW264.7 cells. Based on the assumption that spore-bound RC1 enters phagosomes by "piggyback phagocytosis," model calculations showed that the intraphagosomal concentration of RC1 would greatly exceed its extracellular concentration. Murine alveolar macrophages took up fluorescently labeled retrocyclin, suggesting that macrophages may also acquire extracellular RC1 directly. Overall, these data demonstrate that retrocyclins are effective in vivo against experimental murine anthrax infections and suggest that enhanced macrophage function contributes to this property.