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Single-Molecule Investigation of the Binding Interface Stability of SARS-CoV-2 Variants with ACE2. ACS NANOSCIENCE AU 2024; 4:136-145. [PMID: 38644967 PMCID: PMC11027127 DOI: 10.1021/acsnanoscienceau.3c00060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 04/23/2024]
Abstract
The SARS-CoV-2 pandemic spurred numerous research endeavors to comprehend the virus and mitigate its global severity. Understanding the binding interface between the virus and human receptors is pivotal to these efforts and paramount to curbing infection and transmission. Here we employ atomic force microscopy and steered molecular dynamics simulation to explore SARS-CoV-2 receptor binding domain (RBD) variants and angiotensin-converting enzyme 2 (ACE2), examining the impact of mutations at key residues upon binding affinity. Our results show that the Omicron and Delta variants possess strengthened binding affinity in comparison to the Mu variant. Further, using sera from individuals either vaccinated or with acquired immunity following Delta strain infection, we assess the impact of immunity upon variant RBD/ACE2 complex formation. Single-molecule force spectroscopy analysis suggests that vaccination before infection may provide stronger protection across variants. These results underscore the need to monitor antigenic changes in order to continue developing innovative and effective SARS-CoV-2 abrogation strategies.
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Deciphering molecular mechanisms stabilizing the reovirus-binding complex. Proc Natl Acad Sci U S A 2023; 120:e2220741120. [PMID: 37186838 PMCID: PMC10214207 DOI: 10.1073/pnas.2220741120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 04/06/2023] [Indexed: 05/17/2023] Open
Abstract
Mammalian orthoreoviruses (reoviruses) serve as potential triggers of celiac disease and have oncolytic properties, making these viruses potential cancer therapeutics. Primary attachment of reovirus to host cells is mainly mediated by the trimeric viral protein, σ1, which engages cell-surface glycans, followed by high-affinity binding to junctional adhesion molecule-A (JAM-A). This multistep process is thought to be accompanied by major conformational changes in σ1, but direct evidence is lacking. By combining biophysical, molecular, and simulation approaches, we define how viral capsid protein mechanics influence virus-binding capacity and infectivity. Single-virus force spectroscopy experiments corroborated by in silico simulations show that GM2 increases the affinity of σ1 for JAM-A by providing a more stable contact interface. We demonstrate that conformational changes in σ1 that lead to an extended rigid conformation also significantly increase avidity for JAM-A. Although its associated lower flexibility impairs multivalent cell attachment, our findings suggest that diminished σ1 flexibility enhances infectivity, indicating that fine-tuning of σ1 conformational changes is required to successfully initiate infection. Understanding properties underlying the nanomechanics of viral attachment proteins offers perspectives in the development of antiviral drugs and improved oncolytic vectors.
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Paired immunoglobulin-like receptor B is an entry receptor for mammalian orthoreovirus. Nat Commun 2023; 14:2615. [PMID: 37147336 PMCID: PMC10163058 DOI: 10.1038/s41467-023-38327-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 04/25/2023] [Indexed: 05/07/2023] Open
Abstract
Mammalian orthoreovirus (reovirus) infects most mammals and is associated with celiac disease in humans. In mice, reovirus infects the intestine and disseminates systemically to cause serotype-specific patterns of disease in the brain. To identify receptors conferring reovirus serotype-dependent neuropathogenesis, we conducted a genome-wide CRISPRa screen and identified paired immunoglobulin-like receptor B (PirB) as a receptor candidate. Ectopic expression of PirB allowed reovirus binding and infection. PirB extracelluar D3D4 region is required for reovirus attachment and infectivity. Reovirus binds to PirB with nM affinity as determined by single molecule force spectroscopy. Efficient reovirus endocytosis requires PirB signaling motifs. In inoculated mice, PirB is required for maximal replication in the brain and full neuropathogenicity of neurotropic serotype 3 (T3) reovirus. In primary cortical neurons, PirB expression contributes to T3 reovirus infectivity. Thus, PirB is an entry receptor for reovirus and contributes to T3 reovirus replication and pathogenesis in the murine brain.
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Enhanced drug delivery to cancer cells through a pH-sensitive polycarbonate platform. Biomater Sci 2023; 11:908-915. [PMID: 36533676 PMCID: PMC9890502 DOI: 10.1039/d2bm01626e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
Polymer-drug conjugates are widely investigated to enhance the selectivity of therapeutic drugs to cancer cells, as well as increase circulation lifetime and solubility of poorly soluble drugs. In order to direct these structures selectively to cancer cells, targeting agents are often conjugated to the nanoparticle surface as a strategy to limit drug accumulation in non-cancerous cells and therefore reduce systemic toxicity. Here, we report a simple procedure to generate biodegradable polycarbonate graft copolymer nanoparticles that allows for highly efficient conjugation and intracellular release of S-(+)-camptothecin, a topoisomerase I inhibitor widely used in cancer therapy. The drug-polymer conjugate showed strong efficacy in inhibiting cell proliferation across a range of cancer cell lines over non-cancerous phenotypes, as a consequence of the increased intracellular accumulation and subsequent drug release specifically in cancer cells. The enhanced drug delivery towards cancer cells in vitro demonstrates the potential of this platform for selective treatments without the addition of targeting ligands.
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Modulating Macrophage Clearance of Nanoparticles: Comparison of Small-Molecule and Biologic Drugs as Pharmacokinetic Modifiers of Soft Nanomaterials. Mol Pharm 2022; 19:4080-4097. [PMID: 36069540 DOI: 10.1021/acs.molpharmaceut.2c00528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nanomedicines show benefits in overcoming the limitations of conventional drug delivery systems by reducing side effects, toxicity, and exhibiting enhanced pharmacokinetic (PK) profiles to improve the therapeutic window of small-molecule drugs. However, upon administration, many nanoparticles (NPs) prompt induction of host innate immune responses, which in combination with other clearance pathways such as renal and hepatic, eliminate up to 99% of the administered dose. Here, we explore a drug predosing strategy to transiently suppress the mononuclear phagocyte system (MPS), subsequently improving the PK profile and biological behaviors exhibited by a model NP system [hyperbranched polymers (HBPs)] in an immunocompetent mouse model. In vitro assays allowed the identification of five drug candidates that attenuated cellular association. Predosing of lead compounds chloroquine (CQ) and zoledronic acid (ZA) further showed increased HBP retention within the circulatory system of mice, as shown by both fluorescence imaging and positron emission tomography-computed tomography. Flow cytometric evaluation of spleen and liver tissue cells following intravenous administration further demonstrated that CQ and ZA significantly reduced HBP association with myeloid cells by 23 and 16%, respectively. The results of this study support the use of CQ to pharmacologically suppress the MPS to improve NP PKs.
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Atomic force microscopy applied to interrogate nanoscale cellular chemistry and supramolecular bond dynamics for biomedical applications. Chem Commun (Camb) 2022; 58:5072-5087. [PMID: 35315846 DOI: 10.1039/d1cc07200e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding biological interactions at a molecular level grants valuable information relevant to improving medical treatments and outcomes. Among the suite of technologies available, Atomic Force Microscopy (AFM) is unique in its ability to quantitatively probe forces and receptor-ligand interactions in real-time. The ability to assess the formation of supramolecular bonds and intermediates in real-time on surfaces and living cells generates important information relevant to understanding biological phenomena. Combining AFM with fluorescence-based techniques allows for an unprecedented level of insight not only concerning the formation and rupture of bonds, but understanding medically relevant interactions at a molecular level. As the ability of AFM to probe cells and more complex models improves, being able to assess binding kinetics, chemical topographies, and garner spectroscopic information will likely become key to developing further improvements in fields such as cancer, nanomaterials, and virology. The rapid response to the COVID-19 crisis, producing information regarding not just receptor affinities, but also strain-dependent efficacy of neutralizing nanobodies, demonstrates just how viable and integral to the pre-clinical development of information AFM techniques are in this era of medicine.
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Fluorophore Selection and Incorporation Contribute to Permeation and Distribution Behaviors of Hyperbranched Polymers in Multi-Cellular Tumor Spheroids and Xenograft Tumor Models. ACS APPLIED BIO MATERIALS 2021; 4:2675-2685. [DOI: 10.1021/acsabm.0c01616] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Minimalist style boot improves running but not walking economy in trained men. ERGONOMICS 2020; 63:1329-1335. [PMID: 32588761 DOI: 10.1080/00140139.2020.1778096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 05/28/2020] [Indexed: 06/11/2023]
Abstract
This study examined movement economy under load with 1000 g minimalist (MIN) vs. 1600 g traditional (TRD) style boots. Fourteen trained, male participants completed a VO2peak test (46.6 ± 7.3 ml/kg/min) while wearing a 16 kg external load. Treadmill speeds for the running economy (RE) trials were determined by the slowest pace in which participants completed a full stage with a running gait pattern during the VO2peak test. Walking economy (WE) pace was 1.6 km/h slower than RE pace. During the second session, participants completed 5-min exercise bouts at WE and RE pace under load wearing MIN and TRD. There were no differences for any measured variables during WE trials. In contrast, RE (MIN = 2.95 ± 0.28 vs. TRD = 3.04 ± 0.30 L/min; p = .003: Cohen's d = 0.32), respiratory exchange ratio (p < .001), and perceptual measures (p < .05) were all improved while wearing MIN. Practitioner summary: In trained men, 1000 g/pair minimalist style boots (MIN) resulted in improvements of approximately 3% and 5% for running economy and respiratory exchange ratio versus 1600 g/pair traditional boots while wearing a 16 kg kit. Perceptual responses, including comfort, also favoured MIN. These effects were not found at walking pace. Abbreviations: MIN: minimalist style boots; TRD: traditional style boots; RE: running economy; WE: walking economy; ES: effect size; RER: respiratory exchange ratio; HR: heart rate.
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Targeted and modular architectural polymers employing bioorthogonal chemistry for quantitative therapeutic delivery. Chem Sci 2020; 11:3268-3280. [PMID: 34122834 PMCID: PMC8157365 DOI: 10.1039/d0sc00078g] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
There remain several key challenges to existing therapeutic systems for cancer therapy, such as quantitatively determining the true, tissue-specific drug release profile in vivo, as well as reducing side-effects for an increased standard of care. Hence, it is crucial to engineer new materials that allow for a better understanding of the in vivo pharmacokinetic/pharmacodynamic behaviours of therapeutics. We have expanded on recent “click-to-release” bioorthogonal pro-drug activation of antibody-drug conjugates (ADCs) to develop a modular and controlled theranostic system for quantitatively assessing site-specific drug activation and deposition from a nanocarrier molecule, by employing defined chemistries. The exploitation of quantitative imaging using positron emission tomography (PET) together with pre-targeted bioorthogonal chemistries in our system provided an effective means to assess in real-time the exact amount of active drug administered at precise sites in the animal; our methodology introduces flexibility in both the targeting and therapeutic components that is specific to nanomedicines and offers unique advantages over other technologies. In this approach, the in vivo click reaction facilitates pro-drug activation as well as provides a quantitative means to investigate the dynamic behaviour of the therapeutic agent. There remain several key challenges to existing therapeutic systems for cancer therapy, such as quantitatively determining the true, tissue-specific drug release profile in vivo, as well as reducing side-effects for an increased standard of care.![]()
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Oral Delivery of Multicompartment Nanomedicines for Colorectal Cancer Therapeutics: Combining Loco‐Regional Delivery with Cell‐Target Specificity. ADVANCED THERAPEUTICS 2019. [DOI: 10.1002/adtp.201900171] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Engineered Polymeric Materials for Biological Applications: Overcoming Challenges of the Bio-Nano Interface. Polymers (Basel) 2019; 11:E1441. [PMID: 31480780 PMCID: PMC6780590 DOI: 10.3390/polym11091441] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/28/2019] [Accepted: 08/29/2019] [Indexed: 12/11/2022] Open
Abstract
Nanomedicine has generated significant interest as an alternative to conventional cancertherapy due to the ability for nanoparticles to tune cargo release. However, while nanoparticletechnology has promised significant benefit, there are still limited examples of nanoparticles inclinical practice. The low translational success of nanoparticle research is due to the series ofbiological roadblocks that nanoparticles must migrate to be effective, including blood and plasmainteractions, clearance, extravasation, and tumor penetration, through to cellular targeting,internalization, and endosomal escape. It is important to consider these roadblocks holistically inorder to design more effective delivery systems. This perspective will discuss how nanoparticlescan be designed to migrate each of these biological challenges and thus improve nanoparticledelivery systems in the future. In this review, we have limited the literature discussed to studiesinvestigating the impact of polymer nanoparticle structure or composition on therapeutic deliveryand associated advancements. The focus of this review is to highlight the impact of nanoparticlecharacteristics on the interaction with different biological barriers. More specific studies/reviewshave been referenced where possible.
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Polymer design and component selection contribute to uptake, distribution & trafficking behaviours of polyethylene glycol hyperbranched polymers in live MDA-MB-468 breast cancer cells. Biomater Sci 2019; 7:4661-4674. [PMID: 31469127 DOI: 10.1039/c9bm00957d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
As polymeric nanomedicines grow increasingly complex in design, an effective therapeutic release is often inherently tied to localisation to specific intracellular compartments or microenvironments. The inclusion of environmentally-sensitive moieties links the functionality of such materials to the trafficking behaviours exhibited once materials have obtained access to the cellular milieu. In order to perform their designed function, such materials often need to encounter specific biological cues or stimuli. As such, there is an increased need to improve our understanding of how the physicochemical properties of nanomaterials influence post-internalisation behaviours. Amongst the unknown factors that may contribute to the trafficking behaviours and distribution of polymers within the cellular environment, is the influence of the components selected in the development of such materials. To examine whether composition and arrangement of components within small polymeric nanomaterials contribute to their ability to navigate the intracellular space, here we utilise fluorophores to model component selection, varying the fluorescent handle selected and its method of incorporation. We explore the intracellular behaviours of well-characterised hyperbranched polymers in live MDA-MB-468 breast cancer cells in vitro. Changes in distribution as a function of both fluorophore selection and placement are reported, and our data suggest that the individual components used to produce potential nanomedicines are critical to their overall functioning and efficacy. Further to this, through the use of a novel non-conjugated targeting ligand, we demonstrate that there is inherent competition between component-directing factors and cellular influences on the ultimate fate of the polymers. The behaviours reported here suggest that not only does component selection contribute to intracellular processing, but these factors could potentially be harnessed when designing polymers to ensure improved functionality of future materials for therapeutic delivery.
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Viewing ultrasound images in the abortion clinic: clients' and health care professionals' opinions. EUR J CONTRACEP REPR 2019; 24:130-133. [PMID: 30920317 DOI: 10.1080/13625187.2019.1588959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES The U.K guidance recommends that health care professionals (HCPs) offer clients the opportunity to view their pre-abortion ultrasound scan. As the U.K research on this topic is limited, our objectives were to assess current practice and local population needs, through a prospective, observational survey, to improve the quality of abortion care delivery. METHODS Over a 4 month period all clients attending the Sandyford Termination of Pregnancy and Referral (TOPAR) unit for abortion assessment were asked to fill in an anonymous questionnaire. A further questionnaire was distributed to HCPs working in the TOPAR unit. RESULTS A total of 406 questionnaires were analysed. Almost half (n = 194; 47.8%) of respondents had been offered the opportunity to view their ultrasound scan, of whom 31.4% (61/194) had accepted. The majority of those who had accepted (n = 48; 78.7%) concluded that they were more likely to proceed with the abortion or that viewing the scan had made no difference to their decision to proceed. All HCPs (n = 18; 100%) completed the questionnaire, 55.6% (n = 10) of whom responded that they routinely offered viewing. Ultrasound was not routinely offered by 25% (n = 3) and 83.3% (n = 5) of medical and nursing staff, respectively. CONCLUSIONS We found inconsistent practice within our unit. Despite HCPs building rapport with clients prior to the ultrasound, not all clients who wished to have the opportunity to view their scan were identified. It is evident that many clients wish to have the option to choose for themselves whether they want to view their ultrasound scan, rather than be judged by an HCP as someone who might benefit from it.
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Designed multifunctional polymeric nanomedicines: long-term biodistribution and tumour accumulation of aptamer-targeted nanomaterials. Chem Commun (Camb) 2018; 54:11538-11541. [PMID: 30182121 DOI: 10.1039/c8cc05831h] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report a novel multifunctional hyperbranched polymer based on polyethylene glycol (PEG) as a nanomedicine platform that facilitates longitudinal and quantitative 89Zr-PET imaging, enhancing knowledge of nanomaterial biodistribution and pharmacokinetics/pharmacodynamics both in vivo and ex vivo. Anti-VEGF-A DNA aptamer functionalization increased tumour accumulation by >2-fold in a breast cancer model.
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Effects of Surface Charge of Hyperbranched Polymers on Cytotoxicity, Dynamic Cellular Uptake and Localization, Hemotoxicity, and Pharmacokinetics in Mice. Mol Pharm 2017; 14:4485-4497. [PMID: 29116801 DOI: 10.1021/acs.molpharmaceut.7b00611] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Nanoscaled polymeric materials are increasingly being investigated as pharmaceutical products, drug/gene delivery vectors, or health-monitoring devices. Surface charge is one of the dominant parameters that regulates nanomaterial behavior in vivo. In this paper, we demonstrated how control over chemical synthesis allowed manipulation of nanoparticle surface charge, which in turn greatly influenced the in vivo behavior. Three methacrylate/methacrylamide-based monomers were used to synthesize well-defined hyperbranched polymers (HBP) by reversible addition-fragmentation chain transfer (RAFT) polymerization. Each HBP had a hydrodynamic diameter of approximately 5 nm as determined by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Incorporation of a fluorescent moiety within the polymeric nanoparticles allowed determination of how charge affected the in vivo pharmacokinetic behavior of the nanomaterials and the biological response to them. A direct correlation between surface charge, cellular uptake, and cytotoxicity was observed, with cationic HBPs exhibiting higher cellular uptake and cytotoxicity than their neutral and anionic counterparts. Evaluation of the distribution of the differently charged HBPs within macrophages showed that all HBPs accumulated in the cytoplasm, but cationic HBPs also trafficked to, and accumulated within, the nucleus. Although cationic HBPs caused slight hemolysis, this was generally below accepted levels for in vivo safety. Analysis of pharmacokinetic behavior showed that cationic and anionic HBPs had short blood half-lives of 1.82 ± 0.51 and 2.34 ± 0.93 h respectively, compared with 5.99 ± 2.30 h for neutral HBPs. This was attributed to the fact that positively charged surfaces are more readily covered with opsonin proteins and thus more visible to phagocytic cells. This was supported by in vitro flow cytometric and qualitative live cell imaging studies, which showed that cationic HBPs tended to be taken up by macrophages more effectively and rapidly than neutral and anionic particles.
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Using Peptide Aptamer Targeted Polymers as a Model Nanomedicine for Investigating Drug Distribution in Cancer Nanotheranostics. Mol Pharm 2017; 14:3539-3549. [DOI: 10.1021/acs.molpharmaceut.7b00560] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Cytomegalovirus-associated thrombocytopenia treated with thrombopoietin receptor agonist. Intern Med J 2017; 46:1096-9. [PMID: 27633469 DOI: 10.1111/imj.13181] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 03/30/2016] [Accepted: 06/16/2016] [Indexed: 11/27/2022]
Abstract
Symptomatic cytomegalovirus (CMV) in immunocompetent individuals is an uncommon, yet recognised, phenomenon. This report discusses a case of CMV-associated thrombocytopenia refractory to immunomodulation and antivirals. Ultimately, a clinicopathological response was attained with eltrombopag. This is the first report of the efficacy of thrombopoietin receptor agonists in this context. This experience provides insight into possible pathogenic mechanisms of CMV-associated thrombocytopenia and presents a therapeutic option.
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Targeted Nanomaterials: Overcoming Instability of Antibody-Nanomaterial Conjugates: Next Generation Targeted Nanomedicines Using Bispecific Antibodies (Adv. Healthcare Mater. 16/2016). Adv Healthc Mater 2016. [DOI: 10.1002/adhm.201670084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Overcoming Instability of Antibody-Nanomaterial Conjugates: Next Generation Targeted Nanomedicines Using Bispecific Antibodies. Adv Healthc Mater 2016; 5:2055-68. [PMID: 27283923 DOI: 10.1002/adhm.201600263] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 04/20/2016] [Indexed: 12/20/2022]
Abstract
Targeted nanomaterials promise improved therapeutic efficacy, however their application in nanomedicine is limited due to complexities associated with protein conjugations to synthetic nanocarriers. A facile method to generate actively targeted nanomaterials is developed and exemplified using polyethylene glycol (PEG)-functional nanostructures coupled to a bispecific antibody (BsAb) with dual specificity for methoxy PEG (mPEG) epitopes and cancer targets such as epidermal growth factor receptor (EGFR). The EGFR-mPEG BsAb binds with high affinity to recombinant EGFR (KD : 1 × 10(-9) m) and hyperbranched polymer (HBP) consisting of mPEG (KD : 10 × 10(-9) m) and demonstrates higher avidity for HBP compared to linear mPEG. The binding of BsAb-HBP bioconjugate to EGFR on MDA-MB-468 cancer cells is investigated in vitro using a fluorescently labeled polymer, and in in vivo xenograft models by small animal optical imaging. The antibody-targeted nanostructures show improved accumulation in tumor cells compared to non-targeted nanomaterials. This demonstrates a facile approach for tuning targeting ligand density on nanomaterials, by modulating surface functionality. Antibody fragments are tethered to the nanomaterial through simple mixing prior to administration to animals, overcoming the extensive procedures encountered for developing targeted nanomedicines.
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Indicators of population viability in red spruce, Picea rubens. I. Reproductive traits and fecundity. ACTA ACUST UNITED AC 2000. [DOI: 10.1139/b00-065] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Red spruce (Picea rubens Sarg.) has experienced a substantial decline across most of its range in eastern North America over the past century and probably also in the disjunct Ontario populations where it now occurs only in small isolated stands. Measurements of cone and seed traits from natural populations were used as indicators of the reproductive and genetic status of red spruce across the northern margins of its range in Canada. Cone and seed traits were quantified to provide reproductive benchmarks for assessing and monitoring population viability. Reduced fecundity and seedling height growth were observed in some of the smallest Ontario populations, suggesting some inbreeding depression in both vegetative and reproductive components of fitness. Nevertheless, the reproductive status of these small isolated Ontario populations compared favorably with the much larger, more extensive Maritime populations in Nova Scotia and New Brunswick. Significantly higher proportions of aborted (nonpollinated) seeds and lower proportions of filled seeds suggested poorer pollination conditions in the Maritimes in 1996. The proportion of empty seed, which was used to estimate inbreeding levels, was significantly and negatively related to seedling height growth. In the short-term, the Ontario populations, which probably represent relatively recent remnants of a broader past distribution, generally appeared to be quite resilient to the effects of small population size on fecundity and progeny fitness. In the longer term, continuing decline in population sizes and numbers may be expected to erode reproductive success and genetic diversity through the effects of inbreeding, genetic drift, and changes in mating behavior. The reproductive indicators described here have general validity for assessing and monitoring reproductive and genetic aspects of population viability in conifers.Key words: Picea rubens, reproductive success, reproductive fitness indicators, inbreeding, population viability, conservation.
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Abstract
Scrub typhus was once common in north Queensland, but no reports from this region have been published for nearly 30 years, and the focus has turned to cases from the Northern Territory and Western Australia. In 1996, diagnosis of scrub typhus in a Queensland soldier led to recognition of an earlier outbreak with up to 17 cases. Another outbreak occurred a year later with 11 confirmed cases. All cases were in soldiers who had visited a training area near Innisfail. Review of other laboratory diagnoses of scrub typhus shows it is still prevalent in north Queensland, with several "hot spots".
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Effects of induced spatial incoherence on laser light absorption and x-ray conversion at 0.53 microm. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1991; 43:953-960. [PMID: 9905111 DOI: 10.1103/physreva.43.953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Absorption in high-z targets illuminated with 527-nm laser light at high intensity using induced spatial incoherence. APPLIED OPTICS 1990; 29:4447-4452. [PMID: 20577408 DOI: 10.1364/ao.29.004447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We have measured 527-nm absorption for induced spatial incoherence (ISI) and non-ISI illumination of high-Z targets over the 0.5-3.5 x 10(14)-W/cm(2) laser intensity range using energy balance with a custom designed 30-cm diam light integrating sphere. Induced spatial incoherence of the laser beam was produced by inserting echelons in the beam path and operating the laser at wide bandwidth (0.2%). To produce ISI and non-ISI data for comparison, we irradiated a large number of 180-microm diam gold disks with 0.5-1.5-ns pulses with echelons in the beam path with and without wide laser bandwidths. Our data show an increase in absorption of 5-11% for the ISI illuminated targets and also suggest a weaker dependence of absorption on laser intensity for ISI illumination than for non-ISI.
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The assessment of postmenopausal osteoporosis by total body neutron activation analysis. METABOLIC BONE DISEASE & RELATED RESEARCH 1983; 5:65-7. [PMID: 6672538 DOI: 10.1016/0221-8747(83)90003-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Total body calcium (TBCa) was measured using a cyclotron for in vivo neutron activation analysis (IVNAA) in 20 healthy women, 15 women with vertebral compression fractures, and 8 women with wrist fractures. The precision of the technique, using phantoms, was 1.8% for a dose of 13 mSv. A formula for predicted TBCa (TBCap) was derived from the 20 normal women based on span and years postmenopause. The coefficient of variation of TBCa after normalization in the normal women was 6.6%. The mean TBCa values for the vertebral and wrist fracture groups were 69% and 84% of TBCap for women at the time of the menopause. The low TBCa in the wrist fracture group was attributable to post-menopausal bone loss. Of the low TBCa in the vertebral fracture group, about half the loss could be attributed to postmenopausal age and half to other factors.
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Abstract
An irradiation system has been designed, using a neutron beam from a cyclotron, which optimises the uniformity of activation of calcium. Induced activity is measured in a scanning, shadow-shield whole-body counter. Calibration has been effected and reproducibility assessed with three different types of phantom. Corrections were derived for variations in body height, depth and fat thickness. The coefficient of variation for repeated measurements of an anthropomorphic phantom was 1.8% for an absorbed dose equivalent of 13 mSv (1.3 rem). Measurements of total body calcium in 40 normal adults were used to derive normalisation factors which predict the normal calcium in a subject of given size and age. The coefficient of variation of normalised calcium was 6.2% in men and 6.6% in women, with the demonstration of an annual loss of 1.5% after the menopause. The narrow range should make single measurements useful for diagnostic purposes.
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27
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28
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Absorbed dose to man from the Se-75 labeled conjugated bile salt SeHCAT: concise communication. J Nucl Med 1982; 23:157-61. [PMID: 6799623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The absorbed radiation dose that would result from the oral or intravenous administration of SeHCAT (23-[75Se]selena-25-homotaurocholate) has been calculated using the MIRD tables and formulas and data from measurements of whole-body distribution and from long-term whole-body counting in rats, mice, and man. When SeHCAT is administered to normal subjects, the gallbladder is the critical organ, receiving 12 mrad (oral dose) or 22 mrad (i.v.) per microcurie. The whole-body dose is 1 mrad/microCi, whatever the route of administration. In severe hepatic failure the liver might receive 200 mrad/microCi. The activity likely to be used in routine clinical practice is 10 microCi. Where a whole-body counter is used, an activity of 1 microCi has proved adequate. Even at an administered activity of 25 microCi, the absorbed dose is small compared with established techniques of investigating the gastrointestinal tract.
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29
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Measurement of spinal calcium by in vivo neutron activation analysis in osteoporosis. CLINICAL PHYSICS AND PHYSIOLOGICAL MEASUREMENT : AN OFFICIAL JOURNAL OF THE HOSPITAL PHYSICISTS' ASSOCIATION, DEUTSCHE GESELLSCHAFT FUR MEDIZINISCHE PHYSIK AND THE EUROPEAN FEDERATION OF ORGANISATIONS FOR MEDICAL PHYSICS 1981; 2:45-8. [PMID: 7338015 DOI: 10.1088/0143-0815/2/1/007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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30
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[Nuclear medicine]. XIANGGANG HU LI ZA ZHI. THE HONG KONG NURSING JOURNAL 1980:32-5. [PMID: 6453810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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31
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Measurement of 111in DTPA clearance during radionuclide cisternography. EUROPEAN JOURNAL OF NUCLEAR MEDICINE 1978; 3:105-8. [PMID: 582030 DOI: 10.1007/bf00251633] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A new preparation of 111In DTPA for intrathecal administration has been tested and found to be a safe and highly efficacious cisternographic agent. The rate of removal of 111In DTPA from the C.S.F. and from the whole body has been measured and has been found to be of no diagnostic value in the distinction between patients with cerebral atrophy and those with normotensive hydrocephalus. Long-term retention studies show no evidence of significant long-term retention of indium in the C.S.F. The absorbed radiation dose has been investigated and found to be in good agreement with previous estimates based upon extrapolated data.
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32
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New techniques in nuclear medicine. NURSING TIMES 1977; 73:1716-7. [PMID: 928120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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33
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Treatment of congenital dislocation of the hip in the Middle East. Physiotherapy 1977; 63:13-9. [PMID: 840912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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34
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Comparison of absorption of 'slow-Fe' and ferrous sulphate tablets B.P. in patients following partial gastrectomy. Scott Med J 1972; 17:314-5. [PMID: 5077717 DOI: 10.1177/003693307201700906] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Absorption of ‘Slow-Fe’ and Ferrous sulphate tablets B.P. has been compared in patients who have undergone polya partial gastrectomy. No significant difference in absorption between the two preparations has been found.
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35
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36
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A direct intercomparison of two whole-body monitors in the measurement of the absorption of an oral dose of vitamin B 12 labelled with 57 Co and 58 Co. Phys Med Biol 1972; 17:374-80. [PMID: 4627111 DOI: 10.1088/0031-9155/17/3/003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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37
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Total body counting in the assessment of vitamin B12 absorption in patients with pernicious anemia, achlorhydria without pernicious anemia and in acid secretors. Blood 1970; 36:20-7. [PMID: 5421742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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38
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Whole body counting of vitamin B12 58Co absorption supplemented by profile scanning. Scand J Gastroenterol 1970; 5:261-4. [PMID: 4914166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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39
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Application of whole body counting to the measurement of vitamin B12 absorption with reference to achlorhydria. Scand J Gastroenterol 1969; 4:397-405. [PMID: 5351595 DOI: 10.3109/00365526909180624] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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40
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Abstract
This paper reports the results of estimating vitamin B(12) absorption by whole body counting in patients without known gastrointestinal disorder, and in patients with pernicious anaemia, idiopathic achlorhydria, achlorhydria following gastric operations, and various forms of small intestinal disease. Patients with pernicious anaemia absorbed less than 30% of the test dose; they could be distinguished from patients without gastrointestinal abnormality and from most achlorhydric patients who secreted more than 300 mg units of intrinsic factor in the post-histamine hour. Nevertheless, the wide range of normal absorption and the variable absorption from the normal gastrointestinal tract is emphasized and discussed. There is no relation between histamine-stimulated intrinsic factor production and vitamin B(12) absorption in patients with small intestinal disease.
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41
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Intrinsic-factor secretion assessed by direct radioimmunoassay and by total-body counting in patients with achlorhydria and in acid secretors. Lancet 1968; 2:184-8. [PMID: 4173403 DOI: 10.1016/s0140-6736(68)92620-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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42
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Comparison between three radioisotope methods for measuring iron absorption. BRITISH MEDICAL JOURNAL 1967; 3:331-3. [PMID: 6029161 PMCID: PMC1841957 DOI: 10.1136/bmj.3.5561.331] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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43
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Application of a simple whole-body counter to radiation protection. HEALTH PHYSICS 1967; 13:861-867. [PMID: 6035605 DOI: 10.1097/00004032-196708000-00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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44
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Idiopathic pulmonary haemosiderosis with myocarditis. Radio-isotope studies in a patient treated with prednisone. Thorax 1966; 21:220-9. [PMID: 5914994 PMCID: PMC1019029 DOI: 10.1136/thx.21.3.220] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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45
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46
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Diagnosis in General Practice [Abstract]. Proc R Soc Med 1953; 46:353-354. [PMID: 19993811 PMCID: PMC1918631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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