76
|
Hwang PF, Porterfield N, Pannell D, Davis TA, Elster EA. Trauma is danger. J Transl Med 2011; 9:92. [PMID: 21676213 PMCID: PMC3131254 DOI: 10.1186/1479-5876-9-92] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 06/15/2011] [Indexed: 11/10/2022] Open
Abstract
Background Trauma is one of the leading causes of death in young adult patients. Many pre-clinical and clinical studies attempt to investigate the immunological pathways involved, however the true mediators remain to be elucidated. Herein, we attempt to describe the immunologic response to systemic trauma in the context of the Danger model. Data Sources A literature search using PubMed was used to identify pertinent articles describing the Danger model in relation to trauma. Conclusions Our knowledge of Danger signals in relation to traumatic injury is still limited. Danger/alarmin signals are the most proximal molecules in the immune response that have many possibilities for effector function in the innate and acquired immune systems. Having a full understanding of these molecules and their pathways would give us the ability to intervene at such an early stage and may prove to be more effective in blunting the post-injury inflammatory response unlike previously failed cytokine experiments.
Collapse
|
77
|
Davis TA, Landauer MR, Mog SR, Barshishat-Kupper M, Zins SR, Amare MF, Day RM. Response to Moulder et al., “Re: Davis et al., ‘Timing of captopril administration determines radiation protection or radiation sensitization in a murine model of total body irradiation’”. Exp Hematol 2011. [DOI: 10.1016/j.exphem.2011.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
78
|
Barshishat-Kupper M, Mungunsukh O, Tipton AJ, McCart EA, Panganiban RA, Davis TA, Landauer MR, Day RM. Captopril modulates hypoxia-inducible factors and erythropoietin responses in a murine model of total body irradiation. Exp Hematol 2011; 39:293-304. [DOI: 10.1016/j.exphem.2010.12.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 11/04/2010] [Accepted: 12/03/2010] [Indexed: 12/22/2022]
|
79
|
Potter BK, Forsberg JA, Davis TA, Evans KN, Hawksworth JS, Tadaki D, Brown TS, Crane NJ, Burns TC, O'Brien FP, Elster EA. Heterotopic ossification following combat-related trauma. J Bone Joint Surg Am 2010; 92 Suppl 2:74-89. [PMID: 21123594 DOI: 10.2106/jbjs.j.00776] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
|
80
|
Beaird AM, Davis TA, Matthews MA. Deliquescence in the Hydrolysis of Sodium Borohydride by Water Vapor. Ind Eng Chem Res 2010. [DOI: 10.1021/ie100244v] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
81
|
Anam K, Amare MF, Zins SR, Davis TA. Infusion of Lin- bone marrow cells results in multilineage macrochimerism and skin allograft tolerance in minimally conditioned recipient mice. Transpl Immunol 2010; 24:69-75. [PMID: 20950686 DOI: 10.1016/j.trim.2010.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 10/06/2010] [Indexed: 01/08/2023]
Abstract
Donor-specific immunological tolerance using high doses of donor bone marrow cells (BMC) has been demonstrated in mixed chimerism-based tolerance induction protocols; however, the development of graft versus host disease (GVHD) remains a risk. In the present study, we demonstrate that the infusion of low numbers of donor Lin(-) bone marrow cells (Lin(-) BMC) 7 days post allograft transplantation facilitates high level macrochimerism induction and graft tolerance. Full-thickness BALB/c skin allografts were transplanted onto C57BL/6 mice. Mice were treated with anti-CD4 and anti-CD8 mAbs on day 0, +2, +5, +7 and +14 along with low dose busulfan on day +5. A low dose of highly purified Lin(-) BMC from BALB/c donor mice was infused on day +7. Chimerism and clonal cell deletion were evaluated using flow cytometry. Donor-specific tolerance was tested by donor and third-party skin grafting and mixed leukocyte reaction (MLR). Lin(-) BMC infusion with minimal immunosuppression led to stable, mixed, multilineage macrochimerism and long-term allograft survival (>300 days). Mixed donor-recipient macrochimerism was observed. Donor-reactive T cells were clonally deleted and a 130% increase in CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) was observed in the spleen. Tolerant mice subsequently accepted second donor, but not third-party (C3H), skin grafts and recipient splenocytes failed to react with allogeneic donor cells indicating donor-specific immunological tolerance was achieved. We conclude that the infusion of donor Lin(-) BMC without cytoreductive recipient conditioning can induce indefinite survival of skin allografts via mechanisms involving the establishment of a multilineage macrochimeric state principally through clonal deletion of alloreactive T cells and peripherally induced CD4(+)Foxp3(+) Tregs.
Collapse
|
82
|
Suryawan A, Orellana RA, Fiorotto ML, Davis TA. Triennial Growth Symposium: leucine acts as a nutrient signal to stimulate protein synthesis in neonatal pigs. J Anim Sci 2010; 89:2004-16. [PMID: 20935141 DOI: 10.2527/jas.2010-3400] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The postprandial increases in AA and insulin independently stimulate protein synthesis in skeletal muscle of piglets. Leucine is an important mediator of the response to AA. We have shown that the postprandial increase in leucine, but not isoleucine or valine, acutely stimulates muscle protein synthesis in piglets. Leucine increases muscle protein synthesis by modulating the activation of mammalian target of rapamycin (mTOR) complex 1 and signaling components of translation initiation. Leucine increases the phosphorylation of mTOR, 70-kDa ribosomal protein S6 kinase-1, eukaryotic initiation factor (eIF) 4E-binding protein-1, and eIF4G; decreases eIF2α phosphorylation; and increases the association of eIF4E with eIF4G. However, leucine does not affect the upstream activators of mTOR, that is, protein kinase B, adenosine monophosphate-activated protein kinase, and tuberous sclerosis complex 1/2, or the activation of translation elongation regulator, eukaryotic elongation factor 2. The action of leucine can be replicated by α-ketoisocaproate but not by norleucine. Interference by rapamycin with the raptor-mTOR interaction blocks leucine-induced muscle protein synthesis. The acute leucine-induced stimulation of muscle protein synthesis is not maintained for prolonged periods, despite continued activation of mTOR signaling, because circulating AA fall as they are utilized for protein synthesis. However, when circulating AA concentrations are maintained, the leucine-induced stimulation of muscle protein synthesis is maintained for prolonged periods. Thus, leucine acts as a nutrient signal to stimulate translation initiation, but whether this translates into a prolonged increase in protein synthesis depends on the sustained availability of all AA.
Collapse
|
83
|
Sheppard FR, Keiser P, Craft DW, Gage F, Robson M, Brown TS, Petersen K, Sincock S, Kasper M, Hawksworth J, Tadaki D, Davis TA, Stojadinovic A, Elster E. The majority of US combat casualty soft-tissue wounds are not infected or colonized upon arrival or during treatment at a continental US military medical facility. Am J Surg 2010; 200:489-95. [DOI: 10.1016/j.amjsurg.2010.03.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 03/03/2010] [Accepted: 03/03/2010] [Indexed: 11/25/2022]
|
84
|
Stojadinovic A, Eberhardt J, Brown TS, Hawksworth JS, Gage F, Tadaki DK, Forsberg JA, Davis TA, Potter BK, Dunne JR, Elster EA. Development of a Bayesian model to estimate health care outcomes in the severely wounded. J Multidiscip Healthc 2010; 3:125-35. [PMID: 21197361 PMCID: PMC3004592 DOI: 10.2147/jmdh.s11537] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Graphical probabilistic models have the ability to provide insights as to how clinical factors are conditionally related. These models can be used to help us understand factors influencing health care outcomes and resource utilization, and to estimate morbidity and clinical outcomes in trauma patient populations. STUDY DESIGN Thirty-two combat casualties with severe extremity injuries enrolled in a prospective observational study were analyzed using step-wise machine-learned Bayesian belief network (BBN) and step-wise logistic regression (LR). Models were evaluated using 10-fold cross-validation to calculate area-under-the-curve (AUC) from receiver operating characteristics (ROC) curves. RESULTS Our BBN showed important associations between various factors in our data set that could not be developed using standard regression methods. Cross-validated ROC curve analysis showed that our BBN model was a robust representation of our data domain and that LR models trained on these findings were also robust: hospital-acquired infection (AUC: LR, 0.81; BBN, 0.79), intensive care unit length of stay (AUC: LR, 0.97; BBN, 0.81), and wound healing (AUC: LR, 0.91; BBN, 0.72) showed strong AUC. CONCLUSIONS A BBN model can effectively represent clinical outcomes and biomarkers in patients hospitalized after severe wounding, and is confirmed by 10-fold cross-validation and further confirmed through logistic regression modeling. The method warrants further development and independent validation in other, more diverse patient populations.
Collapse
|
85
|
Stojadinovic A, Elster E, Potter BK, Davis TA, Tadaki DK, Brown TS, Ahlers S, Attinger CE, Andersen RC, Burris D, Centeno J, Champion H, Crumbley DR, Denobile J, Duga M, Dunne JR, Eberhardt J, Ennis WJ, Forsberg JA, Hawksworth J, Helling TS, Lazarus GS, Milner SM, Mullick FG, Owner CR, Pasquina PF, Patel CR, Peoples GE, Nissan A, Ring M, Sandberg CGD, Schaden W, Schultz GS, Scofield T, Shawen SB, Sheppard FR, Stannard JP, Weina PJ, Zenilman JM. Combat Wound Initiative Program. Mil Med 2010; 175:18-24. [DOI: 10.7205/milmed-d-10-00156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
86
|
Zins SR, Amare MF, Anam K, Elster EA, Davis TA. Wound trauma mediated inflammatory signaling attenuates a tissue regenerative response in MRL/MpJ mice. JOURNAL OF INFLAMMATION-LONDON 2010; 7:25. [PMID: 20500883 PMCID: PMC2889944 DOI: 10.1186/1476-9255-7-25] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 05/25/2010] [Indexed: 12/14/2022]
Abstract
Background Severe trauma can induce pathophysiological responses that have marked inflammatory components. The development of systemic inflammation following severe thermal injury has been implicated in immune dysfunction, delayed wound healing, multi-system organ failure and increased mortality. Methods In this study, we examined the impact of thermal injury-induced systemic inflammation on the healing response of a secondary wound in the MRL/MpJ mouse model, which was anatomically remote from the primary site of trauma, a wound that typically undergoes scarless healing in this specific strain. Ear-hole wounds in MRL/MpJ mice have previously displayed accelerated healing and tissue regeneration in the absence of a secondary insult. Results Severe thermal injury in addition to distal ear-hole wounds induced marked local and systemic inflammatory responses in the lungs and significantly augmented the expression of inflammatory mediators in the ear tissue. By day 14, 61% of the ear-hole wounds from thermally injured mice demonstrated extensive inflammation with marked inflammatory cell infiltration, extensive ulceration, and various level of necrosis to the point where a large percentage (38%) had to be euthanized early during the study due to extensive necrosis, inflammation and ear deformation. By day 35, ear-hole wounds in mice not subjected to thermal injury were completely closed, while the ear-hole wounds in thermally injured mice exhibited less inflammation and necrosis and only closed partially (62%). Thermal injury resulted in marked increases in serum levels of IL-6, TNFα, KC (CXCL1), and MIP-2α (CXCL2). Interestingly, attenuated early ear wound healing in the thermally injured mouse resulted in incomplete tissue regeneration in addition to a marked inflammatory response, as evidenced by the histological appearance of the wound and increased transcription of potent inflammatory mediators. Conclusion These findings suggest that the observed systemic inflammatory response of a severe thermal injury undoubtedly has an adverse effect on wound healing and tissue regeneration.
Collapse
|
87
|
Davis TA, Landauer MR, Mog SR, Barshishat-Kupper M, Zins SR, Amare MF, Day RM. Timing of captopril administration determines radiation protection or radiation sensitization in a murine model of total body irradiation. Exp Hematol 2010; 38:270-81. [PMID: 20116413 DOI: 10.1016/j.exphem.2010.01.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 01/05/2010] [Accepted: 01/20/2010] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Angiotensin II (Ang II), a potent vasoconstrictor, affects the growth and development of hematopoietic cells. Mixed findings have been reported for the effects of angiotensin-converting enzyme (ACE) inhibitors on radiation-induced injury to the hematopoietic system. We investigated the consequences of different regimens of the ACE inhibitor captopril on radiation-induced hematopoietic injury. MATERIALS AND METHODS C57BL/6 mice were either sham-irradiated or exposed to (60)Co total body irradiation (0.6 Gy/min). Captopril was provided in the water for different time periods relative to irradiation. RESULTS In untreated mice, the survival rate from 7.5 Gy was 50% at 30 days postirradiation. Captopril treatment for 7 days prior to irradiation resulted in radiosensitization with 100% lethality and a rapid decline in mature blood cells. In contrast, captopril treatment beginning 1 hour postirradiation and continuing for 30 days resulted in 100% survival, with improved recovery of mature blood cells and multilineage hematopoietic progenitors. In nonirradiated control mice, captopril biphasically modulated Lin(-) marrow progenitor cell cycling. After 2 days, captopril suppressed G(0)-G(1) transition and a greater number of cells entered a quiescent state. However, after 7 days of captopril treatment Lin(-) progenitor cell cycling increased compared to untreated control mice. CONCLUSION These findings suggest that ACE inhibition affects hematopoietic recovery following radiation by modulating the hematopoietic progenitor cell cycle. The timing of captopril treatment relative to radiation exposure differentially affects the viability and repopulation capacity of spared hematopoietic stem cells and, therefore, can result in either radiation protection or radiation sensitization.
Collapse
|
88
|
Davis TA, Simon DF, Hassler CS, Wilkinson KJ. A novel in situ tool for the exposure and analysis of microorganisms in natural aquatic systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:8240-8244. [PMID: 19924950 DOI: 10.1021/es901492y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
To evaluate the effects of contaminants or nutrient limitation in natural waters, it is often desirable to perform controlled exposures of organisms. While in situ exposures are routine for caged organisms or macrophytes, they are extremely difficult to perform for microorganisms, mainly due to difficulties in designing an exposure device that isolates the cells while allowing rapid equilibration with the external media. In this paper, a stirred underwater biouptake system (SUBS) based on the diffusion of chemicals across a semipermeable membrane housing a controlled population of microorganisms is reported. Cd diffusion through the semipermeable membrane was evaluated by voltammetry using a microelectrode. Comparison of stirred and unstirred solutions demonstrated a significantly increased diffusive flux in the presence of stirring. Lab tests using Chlamydomonas reinhardtii showed that diffusion across the semipermeable membrane was not limiting with respect to the biouptake of Cd. The SUBS device was field tested and the results of viability studies and trace metal biouptake by C. reinhardtii are reported. No diffusion limitation due to the SUBS was observed for Cd under the tested field conditions. The SUBS device was also shown to be useful for field exposures and subsequent measurements of trace metal uptake and viability. The results support the future use of the SUBS for the in situ measurement of phytochelatin/metallothionein production, photosynthetic efficiency, or reporter gene induction of controlled organisms.
Collapse
|
89
|
Davis TA, Stojadinovic A, Anam K, Amare M, Naik S, Peoples GE, Tadaki D, Elster EA. Extracorporeal shock wave therapy suppresses the early proinflammatory immune response to a severe cutaneous burn injury. Int Wound J 2009; 6:11-21. [PMID: 19291111 DOI: 10.1111/j.1742-481x.2008.00540.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Following severe burn injury, persistent inflammation perpetuated by surface eschar, bacterial colonisation and neutrophil proteolytic activity can impede normal healing and result in further tissue damage. Extracorporeal shock wave treatment (ESWT) has been shown in the clinical setting to promote the healing of burn and difficult-to-heal wounds; however, the mechanism is unclear. We investigated the role of ESWT on the early proinflammatory response using a severe, full-thickness and highly inflammatory cutaneous burn wound in a murine model. Various wound-healing parameters were measured and leukocyte infiltration quantitated. A panel of 188 candidate genes known to be involved in acute inflammation and wound healing was screened. We show that ESWT of burn wounds 1 hour postwounding significantly blunts polymorphonuclear neutrophil and macrophage infiltration into the wound. ESWT treatment potently attenuates both CC- and CXC-chemokine expression, acute proinflammatory cytokine expression and extracellular matrix proteolytic activity at the wound margin. Given these findings and the clinical success of ESWT, we speculate that ESWT may be a potential therapeutic modality to treat severe wounds wherein excessive inflammatory responses involving increased levels of inflammatory cells, proinflammatory cytokines and proteases may become self-resolving allowing wound healing to progresses by way of normal physiological repair processes.
Collapse
|
90
|
Davis TA, Mungunsukh O, Zins S, Day RM, Landauer MR. Genistein induces radioprotection by hematopoietic stem cell quiescence. Int J Radiat Biol 2009; 84:713-26. [DOI: 10.1080/09553000802317778] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
91
|
Marrero-Alfonso EY, Beaird AM, Davis TA, Matthews MA. Hydrogen Generation from Chemical Hydrides. Ind Eng Chem Res 2009. [DOI: 10.1021/ie8016225] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
92
|
Anam K, Amare M, Naik S, Szabo KA, Davis TA. Severe tissue trauma triggers the autoimmune state systemic lupus erythematosus in the MRL/++ lupus-prone mouse. Lupus 2009; 18:318-31. [DOI: 10.1177/0961203308097479] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Tissue damage associated with a severe injury can result in profound inflammatory responses that may trigger autoimmune development in lupus-prone individuals. In this study, we investigated the role of a large full-thickness cutaneous burn injury on the early onset of autoimmune disease in lupus-prone MRL/++ mice. MRL/++ mice (chronic model) exhibit autoimmune symptoms at >70 weeks of age, whereas MRL/-Faslpr mice (acute model) develop autoimmune disease in 17–22 weeks due to a lymphoproliferative mutation. Autoimmune disease developed in MRL/++ mice (4–15 weeks post injury) is manifested by skin lesions, vasculitis, epidermal ulcers, cellular infiltration, splenomegaly, lymphadenopathy, hypergammaglobulinemia, elevated autoantibodies and renal pathologies including proteinuria, glomerulonephritis and immune complex deposition; complications that contribute to reduced survival. Transcription studies of wound margin tissue show a correlation between the pathogenic effects of dysregulated IL-1β, IL-6, TNF-α and PGE2 synthesis during early wound healing and early onset of autoimmune disease. Interestingly, MRL/++ mice with healed wounds (30–40 days post burn) strongly rejected skin isografts. Conversely, skin isografts transplanted onto naive age-matched MRL/++ littermates achieved long-term survival. Collectively, these findings suggest that traumatic injury exacerbates inflammatory skin disease and severe multi-organ pathogenesis in lupus-prone mice.
Collapse
|
93
|
Kalis EJJ, Davis TA, Town RM, Van Leeuwen HP. Impact of ionic strength on Cd(II) partitioning between alginate gel and aqueous media. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:1091-1096. [PMID: 19320163 DOI: 10.1021/es802305n] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Alginate gel is representative of polysaccharide-based components of cell walls which contain a large number of negatively charged functional groups. The structural charge gives rise to a Donnan potential in the gel, which impacts significantly on the partitioning of ions between the aqueous medium and the gel. We measured the Donnan potential and partitioning of Cd2+ in alginate gel as a function of ionic strength in the range 1-100 mM. The Cd2+ partition coefficient between gel and medium, as measured by in situ microelectrode voltammetry, reaches values between 10 and 100 in the 0.1-1 mM ionic strength range, and agrees well with Donnan partition calculations based on the charge density of the gels. The total Cd(II) concentration in the gel correlates approximately linearly with the free [Cd2+]gel. The results imply that metal ion activities in the biopolymer gel phase may generally differ drastically from those in the bulk medium to an extent that strongly depends on ionic strength. This feature must be taken into account in estimations of exposure conditions for predictions of bioavailability.
Collapse
|
94
|
Muth E, Fishel SR, Davis TA. A model for examining the role of stress in functional gastrointestinal disorders. Psychother Psychosom Med Psychol 2009. [DOI: 10.1055/s-0029-1208154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
95
|
Davis TA, Kalis EJJ, Pinheiro JP, Town RM, van Leeuwen HP. Cd(II) speciation in alginate gels. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:7242-7247. [PMID: 18939553 DOI: 10.1021/es801068c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Polysaccharides, such as those occurring in cell walls and biofilms, play an important role in metal speciation in natural aqueous systems. This work describes the speciation of Cd(II) in alginate gels chosen as a model system for biogels. The gels are formed by bridging calcium ions at junction zones present along adjacent homopolymeric guluronic acid chain sequences. The free Cd2+ concentration in the gel phase is measured by a novel in situ microelectrode voltammetric technique that monitors the electroactive probe cation Cd2+ by its reduction at a Au-amalgam microelectrode. In situ voltammetric measurement coupled with total Ca(II) and Cd(II) determinations, as well as potentiometric titration, permits the full reconstruction of the charging environment and the cation binding forthe gel phase. Three independent combinations of measuring and modeling the charged gel layer thereby permit accurate prediction of the Donnan potential, psiD, and the Donnan enrichment coefficient, piD. At an ionic strength of 10 mM, Donnan potentials in the gel ranged from approximately -10 to -20 mV, corresponding to an enhancement in the level of free Cd2+ ions in the gel phase relative to the bulk solution by a factor of approximately 3. In contrast, the total level of Cd(II) was found to be enhanced by a factor of approximately 60, resulting predominantly from the specific binding of the Cd bythe uronic acids of the alginate gel. These results emphasize that large differences in Cd(II) speciation can arise due to the combination of specific and electrostatic modes of binding. The results of this speciation analysis, for charged biological gels, have important consequences for mechanistic interpretation of metal biouptake processes involved in complex media.
Collapse
|
96
|
Stojadinovic A, Carlson JW, Schultz GS, Davis TA, Elster EA. Topical advances in wound care. Gynecol Oncol 2008; 111:S70-80. [PMID: 18793796 DOI: 10.1016/j.ygyno.2008.07.042] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 07/07/2008] [Indexed: 01/10/2023]
Abstract
There are fundamental differences between acute wounds that proceed to uncomplicated healing and those that become chronic wounds. Non-healing or chronic wounds can result from a combination of overlapping factors that prevent healing, including local tissue ischemia, repetitive trauma and ischemia/reperfusion injury, presence of tissue necrosis, impaired cellular and systemic host response to stress, and critical bacterial contamination. The bacterial burden in the wound contributes to a sustained inflammatory state, which inhibits normal progression to the proliferative phase of healing, thereby preventing restoration of tissue integrity. Appropriate wound bed preparation removes local barriers to healing and optimizes the tissue environment to achieve wound healing. It is an essential element of wound management that advances endogenous healing as well as the efficacy of topical and other wound therapy. This article will summarize a systematic approach to wound bed preparation using the "TIME" principle, and will highlight important advances in topical wound care.
Collapse
|
97
|
Day RM, Barshishat-Kupper M, Mog SR, McCart EA, Prasanna PGS, Davis TA, Landauer MR. Genistein protects against biomarkers of delayed lung sequelae in mice surviving high-dose total body irradiation. JOURNAL OF RADIATION RESEARCH 2008; 49:361-72. [PMID: 18434686 PMCID: PMC2575019 DOI: 10.1269/jrr.07121] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effects of genistein on 30-day survival and delayed lung injury were examined in C57BL/6J female mice. A single subcutaneous injection of vehicle (PEG-400) or genistein (200 mg/kg) was administered 24 h before total body irradiation (7.75 Gy (60)Co, 0.6 Gy/min). Experimental groups were: No treatment + Sham (NC), Vehicle + Sham (VC), Genistein + Sham (GC), Radiation only (NR), Vehicle + Radiation (VR), Genistein + Radiation (GR). Thirty-day survivals after 7.75 Gy were: NR 23%, VR 53%, and GR 92%, indicating significant protection from acute radiation injury by genistein. Genistein also mitigated radiation-induced weight loss on days 13-28 postirradiation. First generation lung fibroblasts were analyzed for micronuclei 24 h postirradiation. Fibroblasts from the lungs of GR-treated mice had significantly reduced micronuclei compared with NR mice. Collagen deposition was examined by histochemical staining. At 90 days postirradiation one half of the untreated and vehicle irradiated mice had focal distributions of small collagen-rich plaques in the lungs, whereas all of the genistein-treated animals had morphologically normal lungs. Radiation reduced the expression of COX-2, transforming growth factor-beta receptor (TGFbetaR) I and II at 90 days after irradiation. Genistein prevented the reduction in TGFbetaRI. However, by 180 days postirradiation, these proteins normalized in all groups. These results demonstrate that genistein protects against acute radiation-induced mortality in female mice and that GR-treated mice have reduced lung damage compared to NR or VR. These data suggest that genistein is protective against a range of radiation injuries.
Collapse
|
98
|
Davis TA, Pinheiro JP, Grasdalen H, Smidsrød O, van Leeuwen HP. Stability of lead(II) complexes of alginate oligomers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:1673-1679. [PMID: 18441819 DOI: 10.1021/es702350w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The current work reports on the Pb(ll) complexes formed with oligomeric uronic acids (carboxylated saccharide residues) found polymerized in the cell walls and envelopes of algae and bacteria alike. The application of partial acid hydrolysis, size-exclusion chromatography (SEC), 1H NMR, and scanned deposition stripping chronopotentiometry (SSCP) has permitted the determination of stability constants for Pb(II) with both mannuronic (M) and guluronic (G) acid oligomers ranging from the dimer to the pentamer. The determined logarithm of the stability constants range between 4.11 +/- 0.05 and 5.00 +/- 0.04 mol(-1) x dm3 for the eight oligomers studied (pH 6; I = 0.1 mol x dm(-3)). Additional experiments under the same experimental conditions employing galacturonic and glucuronic acid oligomers yielded slightly lower values (2.19 +/- 0.10 to 4.02 +/- 0.07 mol(-1) x dm3) that were expected based on their structure, whereby the monomers which were not included in the alginate oligomer series (unavailable by SEC), yielded the lowest stability constants. This work demonstrates the applicability of the SSCP technique for the determination of stability constants for metal-ligand complexes in which the ligands display relatively low molecular mass. Previous studies on heavy metal interaction with the matrix polysaccharide alginate have largely been restricted to the whole polymer that forms a gel upon binding to network bridging ions such as calcium. The results will be discussed in this context with the emphasis being placed on the relevance of these findings to processes occurring at the biointerface and results from the relevant literature.
Collapse
|
99
|
Davis TA, Amare M, Naik S, Kovalchuk AL, Tadaki D. Differential cutaneous wound healing in thermally injured MRL/MPJ mice. Wound Repair Regen 2007; 15:577-88. [PMID: 17650103 DOI: 10.1111/j.1524-475x.2007.00266.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Adult wound repair occurs with an initial inflammatory response, reepithelialization, and the formation of a permanent scar. MRL/MpJ mice following ear-hole punch biopsies display accelerated healing and tissue regeneration. In this study, we characterized the healing responses in both MRL/MpJ and BALB/c mice following a 15% total body surface area full-thickness cutaneous burn injury. Macroscopic and histological observations show that delayed wound closure in MRL/MpJ mice is accompanied by an increase in edema, reduced neutrophil infiltration, and more prominent eschar. In vivo bromodeoxyuridine labeling showed no defect in keratinocyte proliferation and migration (reepithelialization). In comparison with BALB/c mice, MRL/MpJ wounds had greater collagen deposition, less granulation tissue formation, and contained fewer alpha-smooth muscle actin-positive myofibroblasts. An observed reduction in dermal neutrophil infiltration and myofibroblast development correlated with enhanced angiogenesis. Overall, BALB/c wounds contracted sooner and to a larger degree, resulting in a significant decrease in scar formation. Interestingly, MRL/MpJ mice showed overt abnormalities in hair follicle proliferation, morphogenesis, and subsequent hair regrowth postburn injury. No substantial evidence of tissue regeneration was observed in either BALB/c or MRL/MpJ wounds. Our results convincingly demonstrate that MRL/MpJ skin burn wounds heal with scar formation with delays in two critical wound healing events: wound closure, and myofibroblast development.
Collapse
|
100
|
Jiménez A, Thompson GL, Matthews MA, Davis TA, Crocker K, Lyons JS, Trapotsis A. Compatibility of Medical-Grade Polymers with Dense CO(2). J Supercrit Fluids 2007; 42:366-372. [PMID: 19756235 DOI: 10.1016/j.supflu.2007.05.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This study reports the effect of exposure to liquid carbon dioxide on the mechanical properties of selected medical polymers. The tensile strengths and moduli of fourteen polymers are reported. Materials were exposed to liquid CO(2), or CO(2) + trace amounts of aqueous H(2)O(2), at 6.5 MPa and ambient temperature. Carbon dioxide uptake, swelling, and distortion were observed for the more amorphous polymers while polymers with higher crystallinity showed little effect from CO(2) exposure. Changes in tensile strength were not statistically significant for most plastics, and most indicated good tolerance to liquid CO(2). These results are relevant to evaluating the potential of liquid CO(2)-based sterilization technology.
Collapse
|