1
|
IL-17A Enhances Retinal Neovascularization. Int J Mol Sci 2023; 24:ijms24021747. [PMID: 36675261 PMCID: PMC9866094 DOI: 10.3390/ijms24021747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/13/2023] [Accepted: 01/14/2023] [Indexed: 01/17/2023] Open
Abstract
Retinal neovascularization occurs in proliferative diabetic retinopathy, neovascular glaucoma, and age-related macular degeneration. This type of retinal pathology normally occurs in the later stages of these ocular diseases and is a prevalent cause of vision loss. Previously, we determined that Interleukin (IL)-17A plays a pivotal role in the onset and progression of non-proliferative diabetic retinopathy in diabetic mice. Unfortunately, none of our diabetic murine models progress to proliferative diabetic retinopathy. Hence, the role of IL-17A in vascular angiogenesis, neovascularization, and the onset of proliferative diabetic retinopathy was unclear. In the current study, we determined that diabetes-mediated IL-17A enhances vascular endothelial growth factor (VEGF) production in the retina, Muller glia, and retinal endothelial cells. Further, we determined that IL-17A can initiate retinal endothelial cell proliferation and can enhance VEGF-dependent vascular angiogenesis. Finally, by utilizing the oxygen induced retinopathy model, we determined that IL-17A enhances retinal neovascularization. Collectively, the results of this study provide evidence that IL-17A plays a pivotal role in vascular proliferation in the retina. Hence, IL-17A could be a potentially novel therapeutic target for retinal neovascularization, which can cause blindness in multiple ocular diseases.
Collapse
|
2
|
Anti-IL17A Halts the Onset of Diabetic Retinopathy in Type I and II Diabetic Mice. Int J Mol Sci 2023; 24:ijms24021347. [PMID: 36674854 PMCID: PMC9860974 DOI: 10.3390/ijms24021347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/03/2023] [Accepted: 01/06/2023] [Indexed: 01/12/2023] Open
Abstract
There are ~463 million diabetics worldwide, and more than half have diabetic retinopathy. Yet, treatments are still lacking for non-proliferative diabetic retinopathy. We and others previously provided evidence that Interleukin-17A (IL-17A) plays a pivotal role in non-proliferative diabetic retinopathy. However, all murine studies used Type I diabetes models. Hence, it was the aim of this study to determine if IL-17A induces non-proliferative diabetic retinopathy in Type II diabetic mice, as identified for Type I diabetes. While examining the efficacy of anti-IL-17A as a potential therapeutic in a short-term Type I and a long-term Type II diabetes model; using different routes of administration of anti-IL-17A treatments. Retinal inflammation was significantly decreased (p < 0.05) after Type I-diabetic mice received 1 intravitreal injection, and Type II-diabetic mice received seven intraperitoneal injections of anti-IL-17A. Further, vascular tight junction protein Zonula Occludens-1 (ZO-1) was significantly decreased in both Type I and II diabetic mice, which was significantly increased when mice received anti-IL-17A injections (p < 0.05). Similarly, tight junction protein Occludin degradation was halted in Type II diabetic mice that received anti-IL-17A treatments. Finally, retinal capillary degeneration was halted 6 months after diabetes was confirmed in Type II-diabetic mice that received weekly intraperitoneal injections of anti-IL-17A. These findings provide evidence that IL-17A plays a pivotal role in non-proliferative diabetic retinopathy in Type II diabetic mice, and suggests that anti-IL-17A could be a good therapeutic candidate for non-proliferative diabetic retinopathy.
Collapse
|
3
|
Inhibition of CD40-TRAF6-dependent inflammatory activity halts the onset of diabetic retinopathy in streptozotocin-diabetic mice. Nutr Diabetes 2022; 12:46. [PMID: 36309487 PMCID: PMC9617859 DOI: 10.1038/s41387-022-00225-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 10/11/2022] [Accepted: 10/20/2022] [Indexed: 01/11/2023] Open
Abstract
Diabetes initiates inflammation that can impair the retinal vasculature, and lead to diabetic retinopathy; one of the leading causes of blindness. Inflammatory pathways have been examined as potential therapeutic targets for diabetic retinopathy, but there is still a need for early-stage treatments. We hypothesized that the CD40-TNF Receptor Associated Factor 6 (TRAF6) axis plays a pivotal role in the onset of diabetic retinopathy, and that the CD40-TRAF6 axis would be a prime therapeutic target for early-stage non-proliferative diabetic retinopathy. The CD40-TRAF6 complex can initiate NFκB activation, inflammation, and tissue damage. Further, CD40 and TRAF6 are constitutively expressed on Muller glia, and upregulated in the diabetic retina. Yet the role of the CD40-TRAF6 complex in the onset of diabetic retinopathy is still unclear. In the current study, we examined the CD40-TRAF6 axis in diabetic retinopathy using a small molecule inhibitor (SMI-6877002) on streptozotocin-induced diabetic mice. When CD40-TRAF6-dependent inflammation was inhibited, retinal vascular leakage and capillary degeneration was ameliorated in diabetic mice. Collectively, these data suggest that the CD40-TRAF6 axis plays a pivotal role in the onset of diabetic retinopathy, and could be a novel therapeutic target for early diabetic retinopathy.
Collapse
|
4
|
Retinal Inflammation, Oxidative Stress, and Vascular Impairment Is Ablated in Diabetic Mice Receiving XMD8-92 Treatment. Front Pharmacol 2021; 12:732630. [PMID: 34456740 PMCID: PMC8385489 DOI: 10.3389/fphar.2021.732630] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/02/2021] [Indexed: 12/13/2022] Open
Abstract
The global number of diabetics continues to rise annually. As diabetes progresses, almost all of Type I and more than half of Type II diabetics develop diabetic retinopathy. Diabetic retinopathy is a microvascular disease of the retina, and is the leading cause of blindness in the working-age population worldwide. With such a significant health impact, new drugs are required to halt the blinding threat posed by this visual disorder. The cause of diabetic retinopathy is multifactorial, and an optimal therapeutic would halt inflammation, cease photoreceptor cell dysfunction, and ablate vascular impairment. XMD8-92 is a small molecule inhibitor that blocks inflammatory activity downstream of ERK5 (extracellular signal-related kinase 5) and BRD4 (bromodomain 4). ERK5 elicits inflammation, is increased in Type II diabetics, and plays a pathologic role in diabetic nephropathy, while BRD4 induces retinal inflammation and plays a role in retinal degeneration. Further, we provide evidence that suggests both pERK5 and BRD4 expression are increased in the retinas of our STZ (streptozotocin)-induced diabetic mice. Taken together, we hypothesized that XMD8-92 would be a good therapeutic candidate for diabetic retinopathy, and tested XMD8-92 in a murine model of diabetic retinopathy. In the current study, we developed an in vivo treatment regimen by administering one 100 μL subcutaneous injection of saline containing 20 μM of XMD8-92 weekly, to STZ-induced diabetic mice. XMD8-92 treatments significantly decreased diabetes-mediated retinal inflammation, VEGF production, and oxidative stress. Further, XMD8-92 halted the degradation of ZO-1 (zonula occludens-1), which is a tight junction protein associated with vascular permeability in the retina. Finally, XMD8-92 treatment ablated diabetes-mediated vascular leakage and capillary degeneration, which are the clinical hallmarks of non-proliferative diabetic retinopathy. Taken together, this study provides strong evidence that XMD8-92 could be a potentially novel therapeutic for diabetic retinopathy.
Collapse
|
5
|
Aryl Hydrocarbon Receptor Agonist VAF347 Impedes Retinal Pathogenesis in Diabetic Mice. Int J Mol Sci 2021; 22:4335. [PMID: 33919327 PMCID: PMC8122442 DOI: 10.3390/ijms22094335] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/19/2021] [Accepted: 04/19/2021] [Indexed: 12/17/2022] Open
Abstract
Diabetic retinopathy is the leading cause of blindness in the working-age population worldwide. Although the cause of diabetic retinopathy is multifactorial, IL-17A is a prevalent inflammatory cytokine involved in the promotion of diabetes-mediated retinal inflammation and the progression of diabetic retinopathy. The primary source of IL-17A is Th17 cells, which are T helper cells that have been differentiated by dendritic cells in a proinflammatory cytokine environment. Aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that can manipulate dendritic cell maturation, halt the production of IL-6 (a proinflammatory cytokine), and suppress Th17 cell differentiation. In the current study, we examined the efficacy of an AhR agonist, VAF347, as a potential therapeutic for the onset of non-proliferative diabetic retinopathy in streptozotocin (STZ)-induced diabetic C57BL/6 mice. We determined that diabetes-mediated leukostasis, oxidative stress, and inflammation in the retina of STZ-diabetic mice were all significantly lower when treated with the AhR agonist VAF347. Furthermore, when VAF347 was subcutaneously injected into STZ-diabetic mice, retinal capillary degeneration was ameliorated, which is the hallmark of non-proliferative diabetic retinopathy in this diabetes murine model. Collectively, these findings provide evidence that the AhR agonist VAF347 could be a potentially novel therapeutic for non-proliferative diabetic retinopathy.
Collapse
|
6
|
RORγt Inhibitor-SR1001 Halts Retinal Inflammation, Capillary Degeneration, and the Progression of Diabetic Retinopathy. Int J Mol Sci 2020; 21:E3547. [PMID: 32429598 PMCID: PMC7279039 DOI: 10.3390/ijms21103547] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 01/08/2023] Open
Abstract
Diabetic retinopathy is a diabetes-mediated retinal microvascular disease that is the leading cause of blindness in the working-age population worldwide. Interleukin (IL)-17A is an inflammatory cytokine that has been previously shown to play a pivotal role in the promotion and progression of diabetic retinopathy. Retinoic acid-related orphan receptor gammaT (RORγt) is a ligand-dependent transcription factor that mediates IL-17A production. However, the role of RORγt in diabetes-mediated retinal inflammation and capillary degeneration, as well as its potential therapeutic attributes for diabetic retinopathy has not yet been determined. In the current study, we examined retinal inflammation and vascular pathology in streptozotocin-induced diabetic mice. We found RORγt expressing cells in the retinal vasculature of diabetic mice. Further, diabetes-mediated retinal inflammation, oxidative stress, and retinal endothelial cell death were all significantly lower in RORγt-/- mice. Finally, when a RORγt small molecule inhibitor (SR1001) was subcutaneously injected into diabetic mice, retinal inflammation and capillary degeneration were ameliorated. These findings establish a pathologic role for RORγt in the onset of diabetic retinopathy and identify a potentially novel therapeutic for this blinding disease.
Collapse
MESH Headings
- Animals
- Capillaries/drug effects
- Capillaries/pathology
- Cell Death/genetics
- Cell Survival/drug effects
- Cell Survival/genetics
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/metabolism
- Diabetic Retinopathy/chemically induced
- Diabetic Retinopathy/drug therapy
- Diabetic Retinopathy/metabolism
- Drug Inverse Agonism
- Endothelial Cells/drug effects
- Endothelial Cells/metabolism
- Hyperglycemia/blood
- Hyperglycemia/genetics
- Inflammation/genetics
- Inflammation/metabolism
- Inflammation/pathology
- Interleukin-17/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Nuclear Receptor Subfamily 1, Group F, Member 3/antagonists & inhibitors
- Nuclear Receptor Subfamily 1, Group F, Member 3/genetics
- Nuclear Receptor Subfamily 1, Group F, Member 3/metabolism
- Oxidative Stress/genetics
- Retinal Vessels/drug effects
- Retinal Vessels/metabolism
- Retinal Vessels/pathology
- Sulfonamides/pharmacology
- Sulfonamides/therapeutic use
- Thiazoles/pharmacology
- Thiazoles/therapeutic use
Collapse
|
7
|
Diabetes induces IL-17A-Act1-FADD-dependent retinal endothelial cell death and capillary degeneration. J Diabetes Complications 2019; 33:668-674. [PMID: 31239234 PMCID: PMC6690768 DOI: 10.1016/j.jdiacomp.2019.05.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 04/15/2019] [Accepted: 05/22/2019] [Indexed: 12/19/2022]
Abstract
PURPOSE Diabetes leads to progressive complications such as diabetic retinopathy, which is the leading cause of blindness within the working-age population worldwide. Interleukin (IL)-17A is a cytokine that promotes and progresses diabetes. The objective of this study was to determine the role of IL-17A in retinal capillary degeneration, and to identify the mechanism that induces retinal endothelial cell death. These are clinically meaningful abnormalities that characterize early-stage non-proliferative diabetic retinopathy. METHODS Retinal capillary degeneration was examined in vivo using the streptozotocin (STZ) diabetes murine model. Diabetic-hyperglycemia was sustained for an 8-month period in wild type (C57BL/6) and IL-17A-/- mice to elucidate the role of IL-17A in retinal capillary degeneration. Further, ex vivo studies were performed in retinal endothelial cells to identify the IL-17A-dependent mechanism that induces cell death. RESULTS It was determined that diabetes-induced retinal capillary degeneration was significantly lower in IL-17A-/- mice. Further, retinal endothelial cell death occurred through an IL-17A/IL-17R ➔ Act1/FADD signaling cascade, which caused caspase-mediated apoptosis. CONCLUSION These are the first findings that establish a pathologic role for IL-17A in retinal capillary degeneration. Further, a novel IL-17A-dependent apoptotic mechanism was discovered, which identifies potential therapeutic targets for the early onset of diabetic retinopathy.
Collapse
|
8
|
Diabetes-mediated IL-17A enhances retinal inflammation, oxidative stress, and vascular permeability. Cell Immunol 2019; 341:103921. [PMID: 31076079 DOI: 10.1016/j.cellimm.2019.04.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 04/03/2019] [Accepted: 04/24/2019] [Indexed: 11/25/2022]
Abstract
Diabetic retinopathy is a prevailing diabetes complication, and one of the leading causes of blindness worldwide. IL-17A is a cytokine involved in the onset of diabetic complications. In the current study, we examined the role of IL-17A in the development of retinal inflammation and long-term vascular pathology in diabetic mice. We found IL-17A expressing T cells and neutrophils in the retinal vasculature. Further, the IL-17A receptor was expressed on Muller glia, retinal endothelial cells, and photoreceptors. Finally, diabetes-mediated retinal inflammation, oxidative stress, and vascular leakage were all significantly lower in IL-17A-/- mice. These are all clinically meaningful abnormalities that characterize the onset of diabetic retinopathy.
Collapse
|
9
|
Evolution of lung breathing from a lungless primitive vertebrate. Respir Physiol Neurobiol 2015; 224:11-6. [PMID: 26476056 DOI: 10.1016/j.resp.2015.09.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 09/28/2015] [Accepted: 09/29/2015] [Indexed: 11/25/2022]
Abstract
Air breathing was critical to the terrestrial radiation and evolution of tetrapods and arose in fish. The vertebrate lung originated from a progenitor structure present in primitive boney fish. The origin of the neural substrates, which are sensitive to metabolically produced CO2 and which rhythmically activate respiratory muscles to match lung ventilation to metabolic demand, is enigmatic. We have found that a distinct periodic centrally generated rhythm, described as "cough" and occurring in lamprey in vivo and in vitro, is modulated by central sensitivity to CO2. This suggests that elements critical for the evolution of breathing in tetrapods, were present in the most basal vertebrate ancestors prior to the evolution of the lung. We propose that the evolution of breathing in all vertebrates occurred through exaptations derived from these critical basal elements.
Collapse
|
10
|
Abstract
BACKGROUND Anesthetics have a profound influence on a myriad of autonomic processes. Mechanisms of general anesthesia, and how these mechanisms give rise to the multifaceted state of anesthesia, are largely unknown. The ascending and descending serotonin (5-HT) networks are key modulators of autonomic pathways, and are critically involved in homeostatic reflexes across the motor, somatosensory, limbic and autonomic systems. These 5-HT networks are thought to contribute to anesthetic effects, but how anesthetics affect 5-HT neuron function remains a pertinent question. We hypothesized that the volatile anesthetic isoflurane inhibits action potential discharge of medullary raphé 5-HT neurons. METHODS We conducted extracellular recordings on individual neurons in the medullary raphé region of the unanesthetized in situ perfused brainstem preparation to determine how exposure to isoflurane affects 5-HT neurons. We examined changes in 5-HT neuron baseline firing in response to treatment with either 1, 1.5, or 2% isoflurane. We measured isoflurane concentrations by gas chromatography-mass spectrometry (GC-MS) analysis. RESULTS Exposure to isoflurane inhibited action potential discharge in raphé 5-HT neurons. We document a concentration-dependent inhibition over a range of concentrations approximating isoflurane MAC (minimum alveolar concentration required for surgical anesthesia). Delivered concentrations of isoflurane were confirmed using GC-MS analysis. CONCLUSIONS These findings illustrate that halogenated anesthetics greatly affect 5-HT neuron firing and suggest 5-HT neuron contributions to mechanisms of general anesthesia.
Collapse
|
11
|
Cesium accumulation by aquatic organisms at different trophic levels following an experimental release into a small reservoir. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2011; 102:283-293. [PMID: 21232832 DOI: 10.1016/j.jenvrad.2010.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 12/08/2010] [Accepted: 12/14/2010] [Indexed: 05/30/2023]
Abstract
The rates of accumulation and subsequent loss of stable cesium (¹³³Cs) by organisms at different trophic levels within plankton-based and periphyton-based food chains were measured following the addition of ¹³³Cs into a small reservoir near Aiken, South Carolina, USA. An uptake parameter u (L kg⁻¹ d⁻¹ dry mass) and a loss rate parameter k (d⁻¹) were estimated for each organism using time-series measurements of ¹³³Cs concentrations in water and biota, and these parameters were used to estimate maximum concentrations, times to maximum concentrations, and concentration ratios (C(r)). The maximum ¹³³Cs concentrations for plankton, periphyton, the insect larva Chaoborus punctipennis, which feeds on plankton, and the snail Helisoma trivolvis, which feeds on periphyton, occurred within the first 14 days following the addition, whereas the maximum concentrations for the fish species Lepomis macrochirus and Micropterus salmoides occurred after 170 days. The C(r) based on dry mass for plankton and C. punctipennis were 1220 L kg⁻¹ and 5570 L kg⁻¹, respectively, and were less than the C(r) of 8630 L kg⁻¹ for periphyton and 47,700 L kg⁻¹ for H. trivolvis. Although the C(r) differed between plankton-based and periphyton-based food chains, they displayed similar levels of biomagnification. Biomagnification was also indicated for fish where the C(r) for the mostly nonpiscivorous L. macrochirus of 22,600 L kg⁻¹ was three times less than that for mostly piscivorous M. salmoides of 71,500 L kg⁻¹. Although the C(r) for M. salmoides was greater than those for periphyton and H. trivolvis, the maximum ¹³³Cs concentrations for periphyton and H. trivolvis were greater than that for M. salmoides.
Collapse
|
12
|
Lung respiratory rhythm and pattern generation in the bullfrog: role of neurokinin-1 and mu-opioid receptors. J Comp Physiol B 2009; 179:579-92. [PMID: 19184042 DOI: 10.1007/s00360-009-0339-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 12/29/2008] [Accepted: 01/02/2009] [Indexed: 02/03/2023]
Abstract
Location of the lung respiratory rhythm generator (RRG) in the bullfrog brainstem was investigated by examining neurokinin-1 and mu-opioid receptor (NK1R, muOR) colocalization by immunohistochemistry and characterizing the role of these receptors in lung rhythm and episodic pattern generation. NK1R and muOR occurred in brainstems from all developmental stages. In juvenile bullfrogs a distinct area of colocalization was coincident with high-intensity fluorescent labeling of muOR; high-intensity labeling of muOR was not distinctly and consistently localized in tadpole brainstems. NK1R labeling intensity did not change with development. Similarity in colocalization is consistent with similarity in responses to substance P (SP, NK1R agonist) and DAMGO (muOR agonist) when bath applied to bullfrog brainstems of different developmental stages. In early stage tadpoles and juvenile bullfrogs, SP increased and DAMGO decreased lung burst frequency. In juvenile bullfrogs, SP increased lung burst frequency, episode frequency, but decreased number of lung bursts per episode and lung burst duration. In contrast, DAMGO decreased lung burst frequency and burst cycle frequency, episode frequency, and number of lung bursts per episode but increased all other lung burst parameters. Based on these results, we hypothesize that NK1R and muOR colocalization together with a metamorphosis-related increase in muOR intensity marks the location of the lung RRG but not necessarily the lung episodic pattern generator.
Collapse
|
13
|
μ‐opioid and NK1 receptor immunofluorescence and involvement in the neuroventilation of bullfrogs. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.755.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
14
|
CO
2
chemosensitivity and air breathing in the Alaska blackfish. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1172.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
15
|
Effect of thyrotropin‐releasing hormone on neuroventilation in bullfrogs. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.954.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
16
|
THE EFFECT OF EXERCISE AND BODY POSITION ON THE VENOUS PRESSURE AT THE ANKLE IN PATIENTS HAVING VENOUS VALVULAR DEFECTS. J Clin Invest 2006; 28:559-63. [PMID: 16695712 PMCID: PMC439636 DOI: 10.1172/jci102105] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
17
|
Responses of benthic fish exposed to contaminants in outdoor microcosms--examining the ecological relevance of previous laboratory toxicity tests. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2004; 68:1-12. [PMID: 15110465 DOI: 10.1016/j.aquatox.2004.01.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2003] [Revised: 01/21/2004] [Accepted: 01/21/2004] [Indexed: 05/24/2023]
Abstract
Previous laboratory studies indicate that coal combustion wastes (a mixture composed of fly ash and other lower volume wastes such as bottom ash; hereafter collectively referred to as ash) adversely affect the health of benthic fish (Erimyzon sucetta; lake chubsucker), but fish in these studies were provided with ample uncontaminated food resources. Because aquatic disposal of ash can also adversely affect food resources for benthic fish, we hypothesized that changes in resources might exacerbate the effects of ash on fish observed in laboratory studies. We exposed juvenile E. sucetta in outdoor microcosms to water, sediment, and benthic resources from an ash-contaminated site or a reference site for 45 days and compared our findings to previous laboratory studies. Benthic invertebrate biomass was nearly three times greater in controls compared to ash microcosms. Total organic content of control sediment (41%) was also greater than in ash sediments (17%), suggesting that additional benthic resources may have also been limited in ash microcosms. Benthic invertebrates isolated from the ash microcosms had trace element concentrations (As, Cd, Co, Cr, Cs, Se, Sr, and V) up to 18 times higher than in weathered ash used in laboratory studies. The concentrations of trace elements accumulated by fish reflected the high dietary concentrations encountered in the ash microcosms and were associated with reduced growth (final mass = 0.07 g) and survival (25%) compared to controls (0.37 g and 67%, respectively). Accumulation of trace elements, as well as reductions in growth and survival, were more pronounced than in previous laboratory studies, suggesting that resource conditions may be important in mediating ash toxicity. Taken together, our studies suggest that ash discharge into aquatic systems is a more serious threat to the health of benthic fish than previously predicted based upon laboratory toxicity tests.
Collapse
|
18
|
Metabolic consequences of hypoxic conditioning in Lymnaea stagnalis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2002; 499:225-9. [PMID: 11729882 DOI: 10.1007/978-1-4615-1375-9_35] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
|
19
|
Do semiclassical zero temperature black holes exist? PHYSICAL REVIEW LETTERS 2000; 85:2438-2441. [PMID: 10978076 DOI: 10.1103/physrevlett.85.2438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2000] [Indexed: 05/23/2023]
Abstract
The semiclassical Einstein equations are solved to first order in epsilon = Planck's over 2pi/M2 for the case of a Reissner-Nordström black hole perturbed by the vacuum stress energy of quantized free fields. Massless and massive fields of spin 0, 1/2, and 1 are considered. We show that in all physically realistic cases, macroscopic zero temperature black hole solutions do not exist. Any static zero temperature semiclassical black hole solutions must then be microscopic and isolated in the space of solutions; they do not join smoothly onto the classical extreme Reissner-Nordström solution as epsilon-->0.
Collapse
|
20
|
The respiratory central pattern generator of Lymnaea: a model, measured and malleable. RESPIRATION PHYSIOLOGY 2000; 122:197-207. [PMID: 10967344 DOI: 10.1016/s0034-5687(00)00159-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Great progress has been made, and continues to be made in our understanding of the neuronal mechanisms underlying respiration in a wide variety of model systems. The central pattern generator (CPG) controlling aerial respiration in the pond-snail Lymnaea is a particularly well-studied model. Using in vitro and semi-intact preparations, the neural circuitry that controls aerial respiration has been characterized as consisting of three identified interneurons. Furthermore, insight has been gained into the behavioural, cellular and synaptic mechanisms by which this circuit controls respiratory rhythmogenesis. It has also been demonstrated that aerial respiratory behaviour can be modified both by experience and by environmental factors. Studies have shown that, in a behavioural hierarchy, respiration is subservient to the whole-body withdrawal response that respiratory behaviour can be modified through operant conditioning, and that respiratory behaviour is altered by hypoxia. Through research on the Lymnaea respiratory CPG we are coming to a better understanding of the construction and malleability of a CPG network. The malleability of this CPG is of particular interest. No longer can neuronal networks underlying respiratory behaviour be considered hard-wired; they have inherent plasticity.
Collapse
|
21
|
Use of isolated digestive-gland cells in the study of biochemical and physiological processes in gastropod molluscs. Comp Biochem Physiol A Mol Integr Physiol 2000; 125:497-502. [PMID: 10840225 DOI: 10.1016/s1095-6433(00)00181-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We describe a method for preparation and maintenance of isolated digestive-gland cells in the abalone, Haliotis kamtschatkana. Viability of the isolated cells was confirmed by the fact that 18 h after preparation the cells exhibited less than 5% staining with trypan blue and actively synthesized glycogen following the addition of glucose substrate. Use of the method in a 15-month study of metabolic activity of the digestive gland of H. kamtschatkana showed significant differences in oxygen consumption of isolated-cell preparations correlated with seasonal differences in somatic and gametogenetic growth, and with relative size of the digestive gland.
Collapse
|
22
|
Verbatim: J B-A. JOURNAL OF PASTORAL CARE 2000; 54:211-5. [PMID: 11067532 DOI: 10.1177/002234090005400214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
|
23
|
The new work of the nonprofit board. HARVARD BUSINESS REVIEW 1996; 74:36-46. [PMID: 10160159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Too often, the board of a nonprofit organization is little more than a collection of high-powered people engaged in low-level activities. But that can change, the authors say, if trustees are willing to discover and take on the new work of the board. When they perform the new work, a board's members can significantly advance the institution's mission and long-term welfare. Doing the new work requires a board to engage in new practices. First, the board must go beyond rubber-stamping management's proposals and find out what issues really matter to the institution. It can do that by making the CEO paint the big picture of the organization's strategic concerns, by understanding key stakeholders, by consulting experts, and by deciding what needs to be measured in order to judge the institution's performance. Second, a board doing the new work must take action: the board must not only set policy but also work with management to implement it. Third, the board must go beyond strictly functional organization: the new work requires flexibility and encourages ad hoc arrangements. Finally, board meetings--where boards underperform most visibly--should be driven by goals, not by processes. The authors give many examples of boards that have successfully embraced the new work. The stakes are high: if boards demonstrate that they can change effectively, the professional staff at the institutions they serve just may follow suit.
Collapse
|
24
|
Is there safety in a home delivery? THE NEBRASKA MEDICAL JOURNAL 1994; 79:32-3. [PMID: 8177352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
|
25
|
Abstract
Mammalian ribosomes have been shown to be enzymatically modified by ribosomal inactivating protein (RIPs) via specific depurination of rRNA. Here we report that ribosomes isolated from wheat germ contain intact and undepurinated rRNA and are depurinated by pokeweed antiviral protein (PAP). Pokeweed ribosomes isolated under the same conditions are depurinated. Total RNA isolated from pokeweed in the presence of strong denaturants was found to pbe partially depurinated. We conclude that wheat germ ribosomes are resistant to the endogenous RIP, tritin, but are sensitive to PAP and that pokeweed ribosomes can be depurinated by the N-glycosidase activity of endogenous PAP during isolation.
Collapse
|
26
|
Abstract
Analyses of particle size distributions indicate that clay minerals and other diagenetic and metamorphic minerals commonly undergo recrystallization by Ostwald ripening. The shapes of their particle size distributions can yield the rate law for this process. One consequence of Ostwald ripening is that a record of the recrystallization process is preserved in the various particle sizes. Therefore, one can determine the detailed geologic history of clays and other recrystallized minerals by separating, from a single sample, the various particle sizes for independent chemical, structural, and isotopic analyses.
Collapse
|
27
|
Etoposide compared with the combination of vincristine, doxorubicin, and cyclophosphamide in the treatment of small cell lung cancer. Thorax 1989; 44:215-9. [PMID: 2539655 PMCID: PMC461757 DOI: 10.1136/thx.44.3.215] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
One hundred and three patients with small cell lung carcinoma were stratified according to stage of disease (47 limited disease, 56 extensive disease) and then randomised to receive etoposide 300 mg/m2 alone for two days or a combination (VAC) of vincristine 1 mg/m2, doxorubicin (Adriamycin) 50 mg/m2, and cyclophosphamide 1000 mg/m2. The drugs were given at three week intervals. Patients were assessed after three cycles of treatment and continued with the same regimen if in complete remission and with the alternative regimen if in partial remission; they were withdrawn if the disease had progressed. Twenty four patients (23%) achieved complete remission and this occurred more often when patients were receiving VAC (19 of 82) than etoposide (5 of 75). There was no difference, however, in overall survival between those initially treated with etoposide and those having combination chemotherapy, whether for limited disease (both 8 months) or extensive disease (7 and 5.5 months). Toxicity was less with etoposide. Survival was disappointing, especially with limited disease, even in patients who showed a complete response to treatment.
Collapse
|
28
|
Charting the territory of nonprofit boards. HARVARD BUSINESS REVIEW 1989; 67:44-48. [PMID: 10291370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
29
|
Cost management techniques. Part II. HOSPITAL MATERIAL[DOLLAR SIGN] MANAGEMENT 1987; 12:12-6. [PMID: 10281749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Reducing the cost of purchased products and services is of continuing importance to hospital purchasing and materials managers. In the first of three articles, the authors addressed the life cycle costing approach applied to purchasing as a means of evaluating total costs over the life of a product rather than only evaluating quoted prices. Life cycle costing is most appropriate for longer lived products, those with maintenance, repair, and disposal considerations. This article continues the discussion of cost management techniques focusing on ways to identify and manage total costs of purchasing and acquisition. The third article will present integrated cost and value management techniques.
Collapse
|
30
|
Cost and value management. Part I. HOSPITAL MATERIAL[DOLLAR SIGN] MANAGEMENT 1987; 12:8-11. [PMID: 10280965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
|
31
|
Keys to successful purchasing and materials management systems. HOSPITAL PURCHASING MANAGEMENT 1985; 10:3-7. [PMID: 10272701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
|
32
|
Trace element analysis of urinary calculi using proton induced X-ray emission (PIXE). BRITISH JOURNAL OF UROLOGY 1982; 54:346-7. [PMID: 6288163 DOI: 10.1111/j.1464-410x.1982.tb08939.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
33
|
Use and abuse of phenolic disinfectants: a preliminary investigation into the possibility of overexposure of babies to phenols. NURSING TIMES 1978; 74:suppl 4-5. [PMID: 643633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
34
|
Trophoblastic disease: case report. MISSOURI MEDICINE 1977; 74:553-6. [PMID: 198647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
35
|
Evaluation of bacteriuria in pregnancy in a predominantly primigravid population. SOUTHWESTERN MEDICINE 1970; 51:57-62. [PMID: 5430573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
36
|
Non-surgical treatment of temporomandibular joint arthrosis. THE JOURNAL OF THE OKLAHOMA STATE MEDICAL ASSOCIATION 1969; 62:421-423. [PMID: 5823698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|