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Robertson JD. AN INVESTIGATION INTO THE THEORIES ON THE FORMATION AND EXIT OF THE INTRA-OCULAR FLUIDS. Br J Ophthalmol 2008; 21:401-48. [PMID: 18169466 DOI: 10.1136/bjo.21.8.401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Mackay G, Stewart CP, Robertson JD. A NOTE ON THE INORGANIC CONSTITUENTS OF NORMAL AND CATARACTOUS HUMAN CRYSTALLINE LENSES. Br J Ophthalmol 2008; 16:193-201. [PMID: 18169020 DOI: 10.1136/bjo.16.4.193] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Robertson JD. THE CHEMICAL EQUILIBRIUM OF THE INTERSTITIAL FLUIDS AND THE AQUEOUS HUMOUR. Br J Ophthalmol 2008; 23:170-90. [PMID: 18169604 DOI: 10.1136/bjo.23.3.170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Robertson JD. THE FLUID EQUILIBRIUM OF THE BODY AND ITS RELATION TO THE EYE. Br J Ophthalmol 2008; 23:106-24. [PMID: 18169595 DOI: 10.1136/bjo.23.2.106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Robertson JD. The effect of haemorrhage of varying degree on blood and plasma volume, on blood sugar, and on arterial blood-pressure. J Physiol 2007; 84:393-409. [PMID: 16994687 PMCID: PMC1394474 DOI: 10.1113/jphysiol.1935.sp003289] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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32
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Noble RL, Robertson JD. The effect of hypertonic solutions on gastric secretion and intraocular pressure. J Physiol 2007; 93:430-7. [PMID: 16995021 PMCID: PMC1393603 DOI: 10.1113/jphysiol.1938.sp003652] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Robertson JD, Williams PC. The creatinine, sugar, and urea equilibrium between plasma and lymph, aqueous humour, cerebro-spinal fluid, and gastric secretion after a hypertonic injection of these solutions. J Physiol 2007; 95:139-47. [PMID: 16995070 PMCID: PMC1393969 DOI: 10.1113/jphysiol.1939.sp003715] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Robertson JD, Stewart CP. The effect of alcohol on the oxygen uptake of brain tissue. Biochem J 2006; 26:65-74. [PMID: 16744815 PMCID: PMC1260872 DOI: 10.1042/bj0260065] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Robertson JD. A POSSIBLE ULTRASTRUCTURAL CORRELATE OF FUNCTION IN THE FROG RETINAL ROD. Proc Natl Acad Sci U S A 2006; 53:860-6. [PMID: 16578595 PMCID: PMC221080 DOI: 10.1073/pnas.53.4.860] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Enoksson M, Robertson JD, Gogvadze V, Bu P, Kropotov A, Zhivotovsky B, Orrenius S. Caspase-2 Permeabilizes the Outer Mitochondrial Membrane and Disrupts the Binding of Cytochrome c to Anionic Phospholipids. J Biol Chem 2004; 279:49575-8. [PMID: 15475367 DOI: 10.1074/jbc.c400374200] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Caspases are cysteine proteases that play a central role in the execution of apoptosis. Recent evidence indicates that caspase-2 is activated early in response to genotoxic stress and can function as an upstream modulator of the mitochondrial apoptotic pathway. In particular, we have shown previously that fully processed caspase-2 can permeabilize the outer mitochondrial membrane and cause cytochrome c and Smac/DIABLO release from these organelles. Using permeabilized cells, isolated mitochondria, and protein-free liposomes, we now report that this effect is direct and depends neither on the presence or cleavage of other proteins nor on a specific phospholipid composition of the liposomal membrane. Interestingly, caspase-2 was also shown to disrupt the interaction of cytochrome c with anionic phospholipids, notably cardiolipin, and thereby enhance the release of the hemoprotein caused by treatment of mitochondria with digitonin or the proapoptotic protein Bax. Combined, our data suggest that caspase-2 possesses an unparalleled ability to engage the mitochondrial apoptotic pathway by permeabilizing the outer mitochondrial membrane and/or by breaching the association of cytochrome c with the inner mitochondrial membrane.
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Robertson JD, Gogvadze V, Kropotov A, Vakifahmetoglu H, Zhivotovsky B, Orrenius S. Processed caspase-2 can induce mitochondria-mediated apoptosis independently of its enzymatic activity. EMBO Rep 2004; 5:643-8. [PMID: 15153933 PMCID: PMC1299073 DOI: 10.1038/sj.embor.7400153] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 03/04/2004] [Accepted: 03/30/2004] [Indexed: 12/21/2022] Open
Abstract
The mechanism by which caspase-2 executes apoptosis remains obscure. Recent findings indicate that caspase-2 is activated early in response to DNA-damaging antineoplastic agents and may be important for the engagement of the mitochondrial apoptotic pathway. We demonstrate here that fully processed caspase-2 stimulates mitochondrial release of cytochrome c and Smac/DIABLO, but not apoptosis-inducing factor (AIF). This event occurs independently of several Bcl-2 family proteins, including Bax, Bak and Bcl-2, and inactivation experiments reveal that the proteolytic activity of caspase-2 is not required for the effect. Further, functional studies of mitochondria indicate that processed caspase-2 stimulates state 4 respiration and decreases the respiratory control ratio as a result of, in large part, an uncoupling effect. Combined, our data suggest that caspase-2 retains a unique ability to engage directly the mitochondrial apoptotic pathway, an effect that requires processing of the zymogen but not the associated catalytic activity.
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Tamm C, Robertson JD, Sleeper E, Enoksson M, Emgård M, Orrenius S, Ceccatelli S. Differential regulation of the mitochondrial and death receptor pathways in neural stem cells. Eur J Neurosci 2004; 19:2613-21. [PMID: 15147295 DOI: 10.1111/j.0953-816x.2004.03391.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite an increasing interest in neural stem cell (NSC) research, relatively little is known about the biochemical regulation of cell death pathways in these cells. We demonstrate here, using murine-derived multipotent C17.2 NSCs, that cells undergo mitochondria-mediated cell death in response to apoptotic stimuli such as oxidative stress induced by 2,3-dimethoxy-1,4-naphthoquinone (DMNQ). In particular, treated cells exhibited apoptotic features, including Bax translocation, cytochrome c release, activation of caspase-9 and -3, chromatin condensation and DNA fragmentation. Although C17.2 cells possess the Fas receptor and express procaspase-8, agonistic Fas mAb treatment failed to induce apoptosis. Fas treatment activated the extracellular signal-regulated protein kinase (ERK) pathway, which may have an antiapoptotic as well as a growth stimulating role. Combined, our findings indicate that while NSCs are sensitive to cytotoxic stimuli that involve an engagement of mitochondria, Fas treatment does not induce death and may have an alternative role.
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Gogvadze V, Robertson JD, Enoksson M, Zhivotovsky B, Orrenius S. Mitochondrial cytochrome c release may occur by volume-dependent mechanisms not involving permeability transition. Biochem J 2004; 378:213-7. [PMID: 14629197 PMCID: PMC1223940 DOI: 10.1042/bj20031193] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Revised: 11/14/2003] [Accepted: 11/20/2003] [Indexed: 11/17/2022]
Abstract
The mechanisms regulating mitochondrial outer-membrane permeabilization and the release of cytochrome c during apoptosis remain controversial. In the present study, we show in an in vitro model system that the release of cytochrome c may occur via moderate modulation of mitochondrial volume, irrespective of the mechanism leading to the mitochondrial swelling. In contrast with mitochondrial permeability transition-dependent release of cytochrome c, in the present study mitochondria remain intact and functionally active.
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Lewis AL, Furze JD, Small S, Robertson JD, Higgins BJ, Taylor S, Ricci DR. Long-term stability of a coronary stent coating post-implantation. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2003; 63:699-705. [PMID: 12418013 DOI: 10.1002/jbm.10387] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A coronary stent possessing a phosphorylcholine-based polymer coating was removed from a human patient 6 months after implantation and analyzed for the presence of the coating. An atomic force microscopy (AFM) technique has been employed to scrape away several 10- micro m(2) areas on the struts of the explanted stent. Scanning-electron microscopy (SEM) and tapping-mode AFM confirmed a surface coating had been removed in each case. Cross-sectional analysis and force-of-removal measurements showed that both coating depth and hardness were characteristic of that for the phosphorylcholine- (PC-) based coating prior to implantation. AFM amplitude-phase and distance curves from the explanted stent were comparable to those obtained when an unused stent was analyzed. Furthermore, laser ablation high-resolution inductively coupled-plasma mass spectometery (LA-HR-ICP-MS) was used to detect the low level of silicon present in the PC coating after explantation. The results from these techniques confirm that the stent coating is the original PC polymer and is not of biological origin, and support the long-term stability of the coating in vivo.
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Robertson JD, Zhivotovsky B, Gogvadze V, Orrenius S. Outer mitochondrial membrane permeabilization: an open-and-shut case? Cell Death Differ 2003; 10:485-7. [PMID: 12728245 DOI: 10.1038/sj.cdd.4401218] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Ewing JC, Robertson JD, Kell WJ, Burnett AK, Ryder D, Chang J, Morgenstern GR, Scarffe JH, Chopra R. Autologous peripheral blood stem cell transplantation in first remission adult acute myeloid leukaemia--an intention to treat analysis and comparison of outcome using a predictive model based on the MRC AML10 cohort. Hematology 2003; 8:83-90. [PMID: 12745657 DOI: 10.1080/1024533031000090793] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The role of autologous peripheral blood stem cell transplantation (APBSCT) in acute myeloid leukaemia (AML) remains controversial. The current study evaluated the application of APBSCT in a large consecutive series of patients with untreated AML, and compared outcome with a predictive model based on MRC AML10 data. Of 148 evaluable patients, 118 patients entered complete remission (CR) after induction therapy comprising three cycles of daunorubicin, cytosine arabinoside and oral 6-thioguanine. Of these patients, 68 (57%) proceeded to consolidation therapy with two courses of intermediate dose cytosine arabinoside, and stem cell mobilisation, and 40 of these patients (34%) underwent the APBSCT procedure after high dose busulphan conditioning. Harvest quality was the main factor precluding APBSCT. Five-year event-free survival (EFS) in patients who achieved CR was 38% and in APBSCT patients was 57%. There were no transplant-related deaths. No significant differences were demonstrated between observed and expected outcomes at 1 and 2 years, based on the predictive model derived from the MRC AML10 study. These data therefore indicate that only a third of eligible adult patients will undergo APBSCT. However, the results demonstrate favourable survival in such patients, with no transplant-related mortality.
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Abstract
Apoptosis is a highly regulated form of cell death distinguished by the activation of a family of cysteine-aspartate proteases (caspases) that cleave various proteins resulting in morphological and biochemical changes characteristic of this form of cell death. Abundant evidence supports a role for mitochondria in regulating apoptosis. Specifically, it seems that a number of death triggers target these organelles and stimulate, by an unknown mechanism, the release of several proteins, including cytochrome c. Once released into the cytosol, cytochrome c binds to its adaptor molecule, apoptotic protease activating factor-1, which oligomerizes and then activates pro-caspase-9. Caspase-9 can signal downstream and activate pro-caspase-3 and -7. The release of cytochrome c can be influenced by different Bcl-2 family member proteins, including Bax, Bid, Bcl-2, and Bcl-X(L). Bax and Bid potentiate cytochrome c release, whereas Bcl-2 and Bcl-X(L) antagonize this event. Although toxicologists have traditionally associated cell death with necrosis, emerging evidence suggests that different types of environmental contaminants exert their toxicity, at least in part, by triggering apoptosis. The mechanism responsible for eliciting the pro-apoptotic effect of a given chemical is often unknown, although in many instances mitochondria appear to be key participants. Here, we provide an overview of our current understanding of the role of apoptosis in toxicant-induced cell death, using dioxin, organotin compounds, dithiocarbamates, as well as the chemotherapeutic agent etoposide, as specific examples.
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Matlock MM, Howerton BS, Robertson JD, Atwood DA. Gold Ore Column Studies with a New Mercury Precipitant. Ind Eng Chem Res 2002. [DOI: 10.1021/ie020006s] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Robertson JD, Enoksson M, Suomela M, Zhivotovsky B, Orrenius S. Caspase-2 acts upstream of mitochondria to promote cytochrome c release during etoposide-induced apoptosis. J Biol Chem 2002; 277:29803-9. [PMID: 12065594 DOI: 10.1074/jbc.m204185200] [Citation(s) in RCA: 313] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
DNA damage induced by the cancer chemotherapeutic drug etoposide triggers the onset of a series of intracellular events characteristic of apoptosis. Among the early changes observed is the release of cytochrome c from mitochondria, although the mechanism responsible for this effect is unclear. We demonstrate here a role for caspase-2 in etoposide-induced cytochrome c release. In particular, Jurkat T-lymphocytes treated with an irreversible caspase-2 inhibitor, benzyloxycarbonyl-Val-Asp-Val-Ala-Asp-fluoromethyl ketone (z-VDVAD-fmk), or stably transfected with pro-caspase-2 antisense (Casp-2/AS) are refractory to cytochrome c release stimulated by etoposide. Experiments performed using a reconstituted cell-free system indicate that etoposide-induced cytochrome c release by way of caspase-2 occurs independently of cytosolic factors, suggesting that the nuclear pool of pro-caspase-2 is critical to this process. Apart from inhibiting cytochrome c release, undermining caspase-2 activity results in an attenuation of downstream events, such as pro-caspase-9 and -3 activation, phosphatidylserine exposure on the plasma membrane, and DNA fragmentation. Taken together, our data indicate that caspase-2 provides an important link between etoposide-induced DNA damage and the engagement of the mitochondrial apoptotic pathway.
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Robertson JD, Chandra J, Gogvadze V, Orrenius S. Biological reactive intermediates and mechanisms of cell death. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2002; 500:1-10. [PMID: 11764918 DOI: 10.1007/978-1-4615-0667-6_1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Robertson JD, Fadeel B, Zhivotovsky B, Orrenius S. 'Centennial' Nobel Conference on apoptosis and human disease. Cell Death Differ 2002; 9:468-75. [PMID: 11965501 DOI: 10.1038/sj.cdd.4401014] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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48
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Robertson JD, Zhivotovsky B. New methodology is a key to progress. Cell Cycle 2002; 1:119-21. [PMID: 12429919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023] Open
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Ott M, Robertson JD, Gogvadze V, Zhivotovsky B, Orrenius S. Cytochrome c release from mitochondria proceeds by a two-step process. Proc Natl Acad Sci U S A 2002; 99:1259-63. [PMID: 11818574 PMCID: PMC122177 DOI: 10.1073/pnas.241655498] [Citation(s) in RCA: 710] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Cytochrome c is often released from mitochondria during the early stages of apoptosis, although the precise mechanisms regulating this event remain unclear. In this study, with isolated liver mitochondria, we demonstrate that cytochrome c release requires a two-step process. Because cytochrome c is present as loosely and tightly bound pools attached to the inner membrane by its association with cardiolipin, this interaction must first be disrupted to generate a soluble pool of this protein. Specifically, solubilization of cytochrome c involves a breaching of the electrostatic and/or hydrophobic affiliations that this protein usually maintains with cardiolipin. Once cytochrome c is solubilized, permeabilization of the outer mitochondrial membrane by Bax is sufficient to allow the extrusion of this protein into the extramitochondrial environment. Neither disrupting the interaction of cytochrome c with cardiolipin, nor permeabilizing the outer membrane with Bax, alone, is sufficient to trigger this protein's release. This mechanism also extends to conditions of mitochondrial permeability transition insofar as cytochrome c release is significantly depressed when the electrostatic interaction between cytochrome c and cardiolipin remains intact. Our results indicate that the release of cytochrome c involves a distinct two-step process that is undermined when either step is compromised.
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MacLean DS, Robertson JD, Jay M. Monitoring the retention of a protein antigen in complete Freund's adjuvant, alum, and pluronic F-127 gel formulations by X-ray fluorescence. Pharm Dev Technol 2001; 6:241-6. [PMID: 11416998 DOI: 10.1081/pdt-100002200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Adjuvants function by protecting antigens from rapid degradation or dispersal. The effectiveness of experimental adjuvants can be assessed by measuring antibody titers to the antigen of interest or, less frequently, by evaluating the retention and distribution of antigen at the application site. In this study, we used X-ray fluorescence (XRF) to monitor the release of an iodinated protein (I-bovine serum albumin) from several adjuvant formulations after its subcutaneous injection in rats. The interaction of the tagged antigen with an external Am-241 source leads to the emission of iodine X-rays from the application site; the number of these X-rays is proportional to the concentration of the protein remaining at the injection site. The disappearance of the iodine X-rays, and hence the antigen, from the injection site followed first-order kinetics for all adjuvant formulations tested; mean half-life values were as follows: in 50% Freund's adjuvant, 17.1 +/- 1.1 h; in 4-hour-old 25% Alum, 11.78 +/- 0.08 h; in 4-h-old 50% Alum, 13.2 +/- 2 h; in 3-day-old 50% Alum, 15.8 +/- 1.5 h; and in 240 mg/mL Pluronic F-127, 7.9 +/- 0.7 h. We conclude that XRF is an easy, reliable, noninvasive method to monitor the retention of antigens in these adjuvant solutions.
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