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Robinson KA, Manning ST, Barber SM, Wobeser BK, Lohmann KL. Congenital hypoplasia of the dorsal colon in a Quarter Horse filly with chronic, intermittent colic. EQUINE VET EDUC 2017. [DOI: 10.1111/eve.12437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- K. A. Robinson
- Department of Large Animal Clinical Sciences; Western College of Veterinary Medicine; University of Saskatchewan; Saskatoon Saskatchewan Canada
| | - S. T. Manning
- Department of Large Animal Clinical Sciences; Western College of Veterinary Medicine; University of Saskatchewan; Saskatoon Saskatchewan Canada
| | - S. M. Barber
- Department of Large Animal Clinical Sciences; Western College of Veterinary Medicine; University of Saskatchewan; Saskatoon Saskatchewan Canada
| | - B. K. Wobeser
- Department of Large Animal Clinical Sciences; Western College of Veterinary Medicine; University of Saskatchewan; Saskatoon Saskatchewan Canada
| | - K. L. Lohmann
- Department of Large Animal Clinical Sciences; Western College of Veterinary Medicine; University of Saskatchewan; Saskatoon Saskatchewan Canada
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Eno NC, Frid CLJ, Hall K, Ramsay K, Sharp RAM, Brazier DP, Hearn S, Dernie KM, Robinson KA, Paramor OAL, Robinson LA. Assessing the sensitivity of habitats to fishing: from seabed maps to sensitivity maps. J Fish Biol 2013; 83:826-846. [PMID: 24090550 DOI: 10.1111/jfb.12132] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In the Welsh part of the Irish Sea, a method was developed for assessing the sensitivity of different seabed habitats to existing fishing activities, across a range of potential fishing intensities. The resistance of 31 habitats and their associated biological assemblage to damage by 14 categories of fishing activity were assessed along with the rate at which each habitat would recover following impact (resilience). Sensitivity was scored based on a combination of the resistance of a habitat to damage and its subsequent rate of recovery. The assessments were based, wherever possible, on scientific literature, with expert judgement used to extrapolate results to habitat and gear combinations not directly examined in the published literature. The resulting sensitivity matrices were then subject to further peer review at a series of workshops. Following consensus on the habitat sensitivity, these data were combined with the most resolved sea-floor habitat maps. These habitat sensitivity maps can help inform the development of site-specific management plans, as well as having a place in spatial planning and aiding managers in developing dialogue with other stakeholders. A case study of their application is provided.
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Affiliation(s)
- N C Eno
- Natural Resources Wales, Maes y Ffynnon, Ffordd Penrhos, Bangor, Gwynedd LL57 2DW, U.K
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Tangpricha V, Kelly A, Stephenson A, Maguiness K, Enders J, Robinson KA, Marshall BC, Borowitz D. An update on the screening, diagnosis, management, and treatment of vitamin D deficiency in individuals with cystic fibrosis: evidence-based recommendations from the Cystic Fibrosis Foundation. J Clin Endocrinol Metab 2012; 97:1082-93. [PMID: 22399505 DOI: 10.1210/jc.2011-3050] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE The objective was to develop evidence-based clinical care guidelines for the screening, diagnosis, management, and treatment of vitamin D deficiency in individuals with cystic fibrosis (CF). PARTICIPANTS The guidelines committee was comprised of physicians, registered dietitians, a pharmacist, a nurse, a parent of an individual with CF, and a health scientist, all with experience in CF. PROCESS Committee members developed questions specific to vitamin D health in individuals with CF. Systematic reviews were completed for each question. The committee reviewed and graded the available evidence and developed evidence-based recommendations and consensus recommendations when insufficient evidence was available. Each consensus recommendation was voted upon by an anonymous process. CONCLUSIONS Vitamin D deficiency is common in CF. Given the limited evidence specific to CF, the committee provided consensus recommendations for most of the recommendations. The committee recommends yearly screening for vitamin D status, preferably at the end of winter, using the serum 25-hydroxyvitamin D measurement, with a minimal 25-hydroxyvitamin D concentration of 30 ng/ml (75 nmol/liter) considered vitamin D sufficient in individuals with CF. Recommendations for age-specific vitamin D intake for all individuals with CF, form of vitamin D, and a stepwise approach to increase vitamin D intake when optimal vitamin D status is not achieved are delineated.
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Abstract
Omnivory is common among arthropods, but little is known about how availability of plant resources and prey affects interactions between species operating at the third and fourth trophic level. We used laboratory and field cage experiments to investigate how the provision of flowers affects an omnivorous lacewing, Micromus tasmaniae (Hemerobiidae) and its parasitoid Anacharis zealandica (Figitidae). The adult lacewing is a true omnivore that feeds on both floral resources and aphids, whereas the parasitoid is a life-history omnivore, feeding on lacewing larvae in the larval stage and floral nectar as an adult. We showed that the effect of floral resources (buckwheat) on lacewing oviposition depends on prey (aphid) density, having a positive effect only at low prey density and that buckwheat substantially increases the longevity of the adult parasitoid. In field cages, we tested how provision of flowering buckwheat affects the dynamics of a four trophic level system, comprising parasitoids, lacewings, pea aphids and alfalfa. We found that provision of buckwheat decreased the density of lacewings in the first phase of the experiment when the density of aphids was high. This effect was probably caused by increased rate of parasitism by the parasitoid, which benefits from the presence of buckwheat. Towards the end of the experiment when the aphid populations had declined to low levels, the effect of buckwheat on lacewing density became positive, probably because lacewings were starving in the no-buckwheat treatment. Although presence of buckwheat flowers did not affect aphid populations in the field cages, these findings highlight the need to consider multitrophic interactions when proposing provision of floral resources as a technique for sustainable pest management.
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Affiliation(s)
- M Jonsson
- Bio-Protection Research Centre, PO Box 84, Lincoln University, Lincoln 7647, New Zealand.
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Segal JB, McNamara RL, Miller MR, Powe NR, Goodman SN, Robinson KA, Bass EB. WITHDRAWN: Anticoagulants or antiplatelet therapy for non-rheumatic atrial fibrillation and flutter. Cochrane Database Syst Rev 2007; 2006:CD001938. [PMID: 17636690 PMCID: PMC10759270 DOI: 10.1002/14651858.cd001938.pub2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) carries a high risk of stroke and other thromboembolic events. Appropriate use of drugs to prevent thromboembolism in patients with AF involves comparing the patient's risk of stroke to the risk of hemorrhage from medication use. OBJECTIVES To quantify risk of stroke, major hemorrhage and death from using medications that have been rigorously evaluated for prevention of thromboembolism in AF. SEARCH STRATEGY Articles were identified through the Cochrane Collaboration's CENTRAL database and MEDLINE until December 1999. SELECTION CRITERIA Included Randomized controlled trials of drugs to prevent thromboembolism in adults with non-postoperative AF. Excluded RCTS of patients with rheumatic valvular disease. DATA COLLECTION AND ANALYSIS Data were abstracted by two reviewers. Odds ratios from all qualitatively similar studies were combined, with weighting by study size, to yield aggregate odds ratios for stroke, major hemorrhage, and death for each drug. MAIN RESULTS Fourteen articles were included in this review. Warfarin was more efficacious than placebo for primary stroke prevention {aggregate odds ratio (OR) of stroke=0.30 [95% Confidence Interval (C.I.) 0.19,0.48]}, with moderate evidence of more major bleeding { OR= 1.90 [95% C.I. 0.89,4.04].}. Aspirin was inconclusively more efficacious than placebo for stroke prevention {OR=0.68 [95% C.I. 0.29,1.57]}, with inconclusive evidence regarding more major bleeds {OR=0.81[95% C.I. 0.37,1.78]}. For primary prevention, assuming a baseline risk of 45 strokes per 1000 patient-years, warfarin could prevent 30 strokes at the expense of only 6 additional major bleeds. Aspirin could prevent 17 strokes, without increasing major hemorrhage. In direct comparison, there was moderate evidence for fewer strokes among patients on warfarin than on aspirin {aggregate OR=0.64[95% C.I. 0.43,0.96]}, with only suggestive evidence for more major hemorrhage {OR =1.58 [95% C.I. 0.76,3.27]}. However, in younger patients, with a mean age of 65 years, the absolute reduction in stroke rate with warfarin compared to aspirin was low (5.5 per 1000 person-years) compared to an older group (15 per 1000 person-years). Low-dose warfarin or low-dose warfarin with aspirin was less efficacious for stroke prevention than adjusted-dose warfarin. AUTHORS' CONCLUSIONS The evidence strongly supports warfarin in AF for patients at average or greater risk of stroke, although clearly there is a risk of hemorrhage. Although not definitively supported by the evidence, aspirin may prove to be useful for stroke prevention in sub-groups with a low risk of stroke, with less risk of hemorrhage than with warfarin. Further studies are needed of low- molecular weight heparin and aspirin in lower risk patients.
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Affiliation(s)
- J B Segal
- Johns Hopkins University, General Internal Medicine, 1830 E. Monument St. 8th Floor, Baltimore, Maryland 21205, USA.
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Beach MC, Cooper LA, Robinson KA, Price EG, Gary TL, Jenckes MW, Gozu A, Smarth C, Palacio A, Feuerstein CJ, Bass EB, Powe NR. Strategies for improving minority healthcare quality. Evid Rep Technol Assess (Summ) 2004:1-8. [PMID: 15164678 PMCID: PMC4781181 DOI: 10.1037/e439452005-001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Bites by the Indian cobra (Naja naja naja) are common in India and Sri Lanka because of its close association with humans. Cobra venoms are complex and contain several toxic components, including neurotoxins that cause post-synaptic neuromuscular blockade with respiratory paralysis and even death. Bites may also cause extensive local necrosis by mechanisms not fully elucidated. Although no significant coagulopathy has been reported, N.n. naja venom can form blood clots in vitro by activating prothrombin as demonstrated by thrombin-specific chromogenic substrate. Scanning electron microscopy demonstrates that the clots formed by venom lack the thin fibrin strands of normal blood clots formed by thromboplastin or glass contact. Rheometry shows that clots formed by venom have abnormally low elasticity over an extended period and then, as the platelets contract, a retarded and more feeble increase in elasticity. Purified N.n. naja venom PLA2 inhibits platelet aggregation in PRP and explains the decreased clot retraction and retarded and compromised elasticity build up. The present study shows that the PLA2 and the prothrombin activator from N.n. naja venom have effects on haemostasis and blood clotting, although such effects are not observed systemically in envenomed humans.
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Affiliation(s)
- I B Sundell
- Department of Haematology, University of Liverpool, Liverpool L69 3GA, UK.
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Watola GV, Stone DA, Smith GC, Forrester GJ, Coleman AE, Coleman JT, Goulding MJ, Robinson KA, Milsom TP. Analyses of two mute swan populations and the effects of clutch reduction: implications for population management. J Appl Ecol 2003. [DOI: 10.1046/j.1365-2664.2003.00811.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Appel LJ, Robinson KA, Guallar E, Erlinger T, Masood SO, Jehn M, Fleisher L, Powe NR, Bass EB. Utility of blood pressure monitoring outside of the clinic setting. Evid Rep Technol Assess (Summ) 2002:1-5. [PMID: 15523745 PMCID: PMC4781018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
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Robinson KA. Preclinical cardiovascular research projects and capabilities at the Atlanta Cardiovascular Research Institute. J Med Assoc Ga 2001; 90:27-31. [PMID: 11845681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The professional and technical staff of the Atlanta Cardiovascular Research Institute preclinical laboratory facility are aggressively pursuing basic and applied research to aid in the understanding of cardiovascular disease and develop new therapeutic approaches. We are optimistic that our intense and broad-ranging research efforts will contribute to important advances in the care of cardiovascular disease patients in the near future and for years to come.
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Affiliation(s)
- K A Robinson
- Atlanta Cardiovascular Research Institute, Medical College of Georgia, USA.
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Catlett C, Perl T, Jenckes MW, Robinson KA, Mitchell D, Hage J, Feuerstein CJ, Chuang S, Bass EB. Training of clinicians for public health events relevant to bioterrorism preparedness. Evid Rep Technol Assess (Summ) 2001:1-4. [PMID: 11899539 PMCID: PMC4780909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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Nakamura M, Barber AJ, Antonetti DA, LaNoue KF, Robinson KA, Buse MG, Gardner TW. Excessive hexosamines block the neuroprotective effect of insulin and induce apoptosis in retinal neurons. J Biol Chem 2001; 276:43748-55. [PMID: 11560942 DOI: 10.1074/jbc.m108594200] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In addition to microvascular abnormalities, neuronal apoptosis occurs early in diabetic retinopathy, but the mechanism is unknown. Insulin may act as a neurotrophic factor in the retina via the phosphoinositide 3-kinase/Akt pathway. Excessive glucose flux through the hexosamine biosynthetic pathway (HBP) is implicated in the development of insulin resistance in peripheral tissues and diabetic complications such as nephropathy. We tested whether increased glucose flux through the HBP perturbs insulin action and induces apoptosis in retinal neuronal cells. Exposure of R28 cells, a model of retinal neurons, to 20 mm glucose for 24 h attenuated the ability of 10 nm insulin to rescue them from serum deprivation-induced apoptosis and to phosphorylate Akt compared with 5 mm glucose. Glucosamine not only impaired the neuroprotective effect of insulin but also induced apoptosis in R28 cells in a dose-dependent fashion. UDP-N-acetylhexosamines (UDP-HexNAc), end products of the HBP, were increased approximately 2- and 15-fold after a 24-h incubation in 20 mm glucose and 1.5 mm glucosamine, respectively. Azaserine, a glutamine:fructose-6-phosphate amidotransferase inhibitor, reversed the effect of 20 mm glucose, but not that of 1.5 mm glucosamine, on attenuation of the ability of insulin to promote cell survival and phosphorylate Akt as well as accumulation of UDP-HexNAc. Glucosamine also impaired insulin receptor processing in a dose-dependent manner but did not decrease ATP content. By contrast, in L6 muscle cells, glucosamine impaired insulin receptor processing but did not induce apoptosis. These results suggest that the excessive glucose flux through the HBP may direct retinal neurons to undergo apoptosis in a bimodal fashion; i.e. via perturbation of the neuroprotective effect of insulin mediated by Akt and via induction of apoptosis possibly by altered glycosylation of proteins. The HBP may be involved in retinal neurodegeneration in diabetes.
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Affiliation(s)
- M Nakamura
- Pennsylvania State Retina Research Group, The Ulerich Ophthalmology Research Center, the Department of Ophthalmology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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Coussement PK, de Leon H, Ueno T, Salame MY, King SB, Chronos NA, Robinson KA. Intracoronary beta-radiation exacerbates long-term neointima formation in balloon-injured pig coronary arteries. Circulation 2001; 104:2459-64. [PMID: 11705825 DOI: 10.1161/hc4401.098516] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Long-term biological effects of ionizing radiation on coronary arteries remain poorly defined. We examined late arterial responses 6 months after balloon angioplasty and beta-radiation in normal pig coronary arteries. METHODS AND RESULTS Coronary arteries of 25 adult pigs were randomized to receive 20 Gy (n=8) or 30 Gy (n=9) of (186)Re beta-radiation or sham radiation (n=8) immediately after balloon angioplasty. Aspirin was given daily during follow-up. The study vessels were analyzed histopathologically at 6 months. beta-Radiation decreased lumen area (20 Gy, 1.55+/-0.99 mm(2); 30 Gy, 1.03+/-0.82 mm(2); and 0 Gy, 2.05+/-0.80 mm(2); P<0.05) but not overall vessel area. The neointimal area was significantly larger within the injured segment with beta-radiation (20 Gy, 1.92+/-1.23 mm(2); 30 Gy, 1.51+/-0.97 mm(2); and 0 Gy, 0.89+/-0.31 mm(2); 0 Gy versus 20 Gy, P<0.05), and a significant increase of edge stenosis was observed with beta-radiation. Irradiated vessels also had larger thrombus areas within the neointima (30 Gy, 0.24+/-0.61 mm(2); 20 Gy, 0.98+/-1.57 mm2; and 0 Gy, 0.00+/-0.01 mm(2); P<0.05) and larger adventitial areas (20 Gy, 2.25+/-0.75 mm(2); 30 Gy, 2.38+/-0.98 mm(2); and 0 Gy, 1.23+/-0.29 mm(2); 0 Gy versus 20 or 30 Gy, P<0.05) that showed substantial collagen accumulation. CONCLUSIONS Intracoronary beta-radiation did not inhibit neointima formation in balloon-injured normal pig coronary arteries 6 months after the interventional procedure. Unresorbed thrombus contributed to, but was not the sole component of, augmented neointima formation. Irradiated vessels demonstrated more adventitial thickening and fibrosis. These observations may have relevance for long-term clinical outcomes after intracoronary beta-radiation.
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Affiliation(s)
- P K Coussement
- Atlanta Cardiovascular Research Institute, Norcross, GA, USA
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Verheye S, Coussement PK, Salame MY, Fallahi P, Cui J, Chronos NA, King SB, Crocker IR, Robinson KA. High-dose external beam irradiation inhibits neointima formation in stented pig coronary arteries. Int J Radiat Oncol Biol Phys 2001; 51:820-7. [PMID: 11697328 DOI: 10.1016/s0360-3016(01)01679-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE To evaluate high-dose external beam irradiation (EBRT) in a pig coronary stent preparation because low and intermediate-dose EBRT failed to show inhibition of neointima formation in stented animal models. METHODS AND MATERIALS Thirty-five stents were implanted in the coronary arteries of 17 pigs. Seven pigs were exposed to a single dose of 21 Gy EBRT immediately after stenting. Ten stented, nonirradiated pigs served as controls. After 4 weeks, the study arteries and myocardium were examined by light and scanning electron microscopy. RESULTS Compared with controls, 21 Gy EBRT resulted in a larger lumen area (7.57 +/- 1.67 mm2 vs. 4.00 +/- 1.63 mm2, p <0.001), a smaller neointima area (0.47 +/- 0.43 mm2 vs. 3.36 +/- 2.26 mm2, p <0.001) and a smaller maximal intimal thickness (0.16 +/- 0.09 mm vs. 0.68 +/- 0.31 mm, p <0.001). Unresorbed intramural hemorrhages and adherent mural thrombi were present in the irradiated vessels, which also showed incomplete re-endothelialization. The irradiated hearts demonstrated diffuse interstitial and perivascular inflammation and fibrosis. CONCLUSIONS EBRT at 21 Gy to the entire heart significantly inhibited neointima formation in stented pig coronary arteries but also resulted in incomplete re-endothelialization, myocardial inflammation, and fibrosis. Improvements in localization and delivery techniques are required to allow clinical implementation of this technique.
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Affiliation(s)
- S Verheye
- Cardiovascular Translational Research Institute, Middelheim, Antwerp, Belgium
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Robinson KA, McNamara RL, Bass EB, Powe NR. Evidence-based practice centers: production of evidence report on management of atrial fibrillation. AACN Clin Issues 2001; 12:618-27. [PMID: 11759433 DOI: 10.1097/00044067-200111000-00018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Healthcare practitioners are increasingly expected to understand and practice evidence-based healthcare. However, to apply evidence-based healthcare methods on an individual basis in a specific clinic or with a specific patient is rarely possible because it is time consuming and requires specialized skills. One way of facilitating evidence-based care is to use evidence-based products produced by others. In 1997, the Agency for Healthcare Research and Quality designated 12 evidence-based practice centers. Since their inception, these evidence-based practice centers have produced 40 evidence reports. This article provides an overview of the purpose and process of evidence-based practice centers using examples from the first evidence report produced by the Johns Hopkins Evidence-based Practice Center. The steps in the process of developing an evidence report include recruitment of experts, refinement of the questions, design of the literature search plan, quality assessment and data abstraction from identified articles, synthesis of evidence, peer review, and dissemination. Each step is defined and illustrated with examples from the development of an evidence report on atrial fibrillation.
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Affiliation(s)
- K A Robinson
- Johns Hopkins Evidence-Based Practice Center, Department of Epidemiology, Bloomberg School of Public Health and Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.
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Abstract
Glutamine:fructose-6-phosphate amidotransferase(GFAT) is the rate-limiting enzyme of the hexosamine synthesis pathway. Products of this pathway have been implicated in insulin resistance and glucose toxicity. GFAT1 is ubiquitous, whereas GFAT2 is expressed mainly in the central nervous system. In the course of developing a competitive reverse transcriptase-polymerase chain reaction assay, we noted that GFAT1 cDNA from muscle but not from other tissues migrated as a doublet. Subsequent cloning and sequencing revealed two GFAT1 mRNAs in both mouse and human skeletal muscles. The novel GFAT1 mRNA (GFAT1Alt [muscle selective variant of GFAT1]) is likely a splice variant. It is identical to GFAT1 except for a 48 or 54 bp insert in the mouse and human, respectively, at nucleotide position 686 of the coding sequence, resulting in a 16 or 18 amino acid insert at position 229 of the protein. GFAT1Alt is the predominant GFAT1 mRNA in mouse hindlimb muscle, is weakly expressed in the heart, and is undetectable in the brain, liver, kidney, lung, intestine, spleen, and 3T3-L1 adipocytes. In humans, it is strongly expressed in skeletal muscle but not in the brain. GFAT1 and GFAT1Alt expressed by recombinant adenovirus infection in COS-7 cells displayed robust enzyme activity and kinetic differences. The apparent K(m) of GFAT1Alt for fructose-6-phosphate was approximately twofold higher than that of GFAT1, whereas K(i) for UDP-N-acetylglucosamine was approximately fivefold lower. Muscle insulin resistance is a hallmark and predictor of type 2 diabetes. Variations in the expression of GFAT isoforms in muscle may contribute to predisposition to insulin resistance.
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Affiliation(s)
- J E DeHaven
- Department of Medicine, Division of Endocrinology, Diabetes and Medical Genetics, Medical University of South Carolina, Charleston 29425, USA
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Greene EL, Nelson BA, Robinson KA, Buse MG. alpha-Lipoic acid prevents the development of glucose-induced insulin resistance in 3T3-L1 adipocytes and accelerates the decline in immunoreactive insulin during cell incubation. Metabolism 2001; 50:1063-9. [PMID: 11555840 DOI: 10.1053/meta.2001.25601] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Oxidative stress has been implicated in glucose toxicity. We tested the hypothesis that certain antioxidants may prevent insulin-resistant glucose transport that develops in adipocytes after sustained exposure to high glucose, provided insulin is present. The antioxidant alpha-lipoic acid has been proposed as an insulin sensitizer. 3T3-L1 adipocytes were preincubated 18 hours in media containing insulin (0.6 nmol/L) with low (5 mmol/L) or high (25 mmol/L) glucose with or without alpha-lipoate, dihydrolipoate (each 0.1 to 0.5 mmol/L), or N-acetylcysteine (1 to 5 mmol/L). After extensive re-equilibration in insulin and antioxidant-free media, basal and maximally insulin-stimulated (100 nmol/L) glucose transport was measured. Insulin was quantified by radioimmunoassay. Preincubation with alpha-lipoate and dihydrolipoate but not N-acetylcysteine increased subsequent basal glucose transport; the effect was much smaller than that of acute maximal insulin stimulation. Preincubation in high glucose without antioxidants inhibited acutely insulin-stimulated glucose transport by 40% to 50% compared with low glucose. This down- regulation was partially or completely prevented by each antioxidant. In cell-free media, the 2 reductants, dihydrolipoate and N-acetylcysteine, rapidly decreased immunoreactive insulin, but alpha-lipoate was ineffective. However, during incubation with adipocytes, alpha-lipoate, and dihydrolipoate promoted the decline in immunoreactive insulin nearly equally. Because insulin and high glucose are synergistic in inducing insulin resistance in this model, the reduction in immunoreactive insulin probably contributed to the protective effect of the antioxidants. 3T3-L1 adipocytes efficiently metabolize alpha-lipoate to dihydrolipoate, which may be released into the medium. The stimulation of glucose transport by alpha-lipoic acid may represent redox effects in subcellular compartments that are accessible to dihydrolipoate.
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Affiliation(s)
- E L Greene
- Division of Endocrinology, Department of Internal Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
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Jampel HD, Lubomski LH, Friedman DS, Robinson KA, Congdon N, Quigley HA, Levkovitch-Verbin H, Kempen J, Bass EB. Surgical treatment of coexisting cataract and glaucoma. Evid Rep Technol Assess (Summ) 2001:1-3. [PMID: 11488137 PMCID: PMC4781005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Robinson KA, Baughman W, Rothrock G, Barrett NL, Pass M, Lexau C, Damaske B, Stefonek K, Barnes B, Patterson J, Zell ER, Schuchat A, Whitney CG. Epidemiology of invasive Streptococcus pneumoniae infections in the United States, 1995-1998: Opportunities for prevention in the conjugate vaccine era. JAMA 2001; 285:1729-35. [PMID: 11277827 DOI: 10.1001/jama.285.13.1729] [Citation(s) in RCA: 464] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT Pneumococcal polysaccharide vaccine is recommended for elderly persons and adults with certain chronic illnesses. Additionally, a recently licensed pneumococcal 7-valent conjugate vaccine has been recommended for use in young children and could dramatically change the epidemiology of pneumococcal disease. OBJECTIVES To assess pneumococcal disease burden in the United States, estimate the potential impact of new vaccines, and identify gaps in vaccine recommendations. DESIGN AND SETTING Analysis of data from the Active Bacterial Core Surveillance (ABCs)/Emerging Infections Program Network, an active, population-based system in 9 states. PATIENTS A total of 15 860 cases of invasive pneumococcal disease occurring between January 1, 1995, and December 31, 1998. MAIN OUTCOME MEASURES Age- and race-specific pneumoccocal disease incidence rates per 100 000 persons, case-fatality rates, and vaccine preventability. RESULTS In 1998, overall incidence was 23.2 cases per 100 000, corresponding to an estimated 62 840 cases in the United States. Incidence was highest among children younger than 2 years (166.9) and adults aged 65 years or older (59.7). Incidence among blacks was 2.6 times higher than among whites (95% confidence interval [CI], 2.4-2.8). Overall, 28.6% of case-patients were at least 65 years old and 85.9% of cases in this age group were due to serotypes included in the 23-valent polysaccharide vaccine; 19.3% of case-patients were younger than 2 years and 82.2% of cases in this age group were due to serotypes included in the 7-valent conjugate vaccine. Among patients aged 2 to 64 years, 50.6% had a vaccine indication as defined by the Advisory Committee on Immunization Practices (ACIP). The case-fatality rate among patients aged 18 to 64 years with an ACIP indication was 12.1% compared with 5.4% for those without an indication (relative risk, 2.2; 95% CI, 1.7-2.9). CONCLUSIONS Young children, elderly persons, and black persons of all ages are disproportionately affected by invasive pneumococcal disease. Current ACIP recommendations do not address a subset of persons aged 18 to 64 years but do include those at highest risk for death from invasive pneumococcal disease.
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Affiliation(s)
- K A Robinson
- Respiratory Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, MS D-65, 1600 Clifton Rd NE, Atlanta, GA 30333, USA.
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21
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MESH Headings
- Angioplasty, Balloon, Coronary/adverse effects
- Angioplasty, Balloon, Coronary/instrumentation
- Angioplasty, Balloon, Coronary/methods
- Angioplasty, Balloon, Coronary/trends
- Animals
- Beta Particles/therapeutic use
- Brachytherapy/adverse effects
- Brachytherapy/instrumentation
- Brachytherapy/methods
- Brachytherapy/trends
- Cardiology/methods
- Cardiology/trends
- Coronary Disease/radiotherapy
- Coronary Disease/surgery
- Disease Models, Animal
- Gamma Rays/therapeutic use
- Humans
- Patient Selection
- Radiation Dosage
- Radiography, Interventional/methods
- Radiography, Interventional/trends
- Radiometry
- Radiotherapy/adverse effects
- Radiotherapy/instrumentation
- Radiotherapy/methods
- Radiotherapy/trends
- Recurrence
- Safety
- Stents/adverse effects
- Treatment Outcome
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Affiliation(s)
- M Y Salame
- The Andreas Gruentzig Cardiovascular Center, Department of Medicine (Cardiology), Emory University School of Medicine, Atlanta, GA, USA
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Lehmann HP, Andrews JS, Robinson KA, Holloway VL, Goodman SN. Management of acne. Evid Rep Technol Assess (Summ) 2001:1-3. [PMID: 11898669 PMCID: PMC4781220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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23
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Segal JB, McNamara RL, Miller MR, Powe NR, Goodman SN, Robinson KA, Bass EB. Anticoagulants or antiplatelet therapy for non-rheumatic atrial fibrillation and flutter. Cochrane Database Syst Rev 2001:CD001938. [PMID: 11279741 DOI: 10.1002/14651858.cd001938] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) carries a high risk of stroke and other thromboembolic events. Appropriate use of drugs to prevent thromboembolism in patients with AF involves comparing the patient's risk of stroke to the risk of hemorrhage from medication use. OBJECTIVES To quantify risk of stroke, major hemorrhage and death from using medications that have been rigorously evaluated for prevention of thromboembolism in AF. SEARCH STRATEGY Articles were identified through the Cochrane Collaboration's CENTRAL database and MEDLINE until December 1999. SELECTION CRITERIA Included Randomized controlled trials of drugs to prevent thromboembolism in adults with non-postoperative AF. Excluded RCTS of patients with rheumatic valvular disease. DATA COLLECTION AND ANALYSIS Data were abstracted by two reviewers. Odds ratios from all qualitatively similar studies were combined, with weighting by study size, to yield aggregate odds ratios for stroke, major hemorrhage, and death for each drug. MAIN RESULTS Fourteen articles were included in this review. Warfarin was more efficacious than placebo for primary stroke prevention [aggregate odds ratio (OR) of stroke=0.30 [95% Confidence Interval (C.I.) 0.19,0.48]], with moderate evidence of more major bleeding [ OR= 1.90 [95% C.I. 0.89,4.04].]. Aspirin was inconclusively more efficacious than placebo for stroke prevention [OR=0.68 [95% C.I. 0.29,1.57]], with inconclusive evidence regarding more major bleeds [OR=0.81[95% C.I. 0.37,1.78]]. For primary prevention, assuming a baseline risk of 45 strokes per 1000 patient-years, warfarin could prevent 30 strokes at the expense of only 6 additional major bleeds. Aspirin could prevent 17 strokes, without increasing major hemorrhage. In direct comparison, there was moderate evidence for fewer strokes among patients on warfarin than on aspirin [aggregate OR=0.64[95% C.I. 0.43,0.96]], with only suggestive evidence for more major hemorrhage [OR =1.58 [95% C.I. 0.76,3.27]]. However, in younger patients, with a mean age of 65 years, the absolute reduction in stroke rate with warfarin compared to aspirin was low (5.5 per 1000 person-years) compared to an older group (15 per 1000 person-years). Low-dose warfarin or low-dose warfarin with aspirin was less efficacious for stroke prevention than adjusted-dose warfarin. REVIEWER'S CONCLUSIONS The evidence strongly supports warfarin in AF for patients at average or greater risk of stroke, although clearly there is a risk of hemorrhage. Although not definitively supported by the evidence, aspirin may prove to be useful for stroke prevention in sub-groups with a low risk of stroke, with less risk of hemorrhage than with warfarin. Further studies are needed of low- molecular weight heparin and aspirin in lower risk patients.
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Affiliation(s)
- J B Segal
- Medicine, Johns Hopkins School of Medicine, 1830 E. Monument St. 8th floor, Baltimore, Maryland 21205, USA.
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Abstract
The Ino4 protein belongs to the basic helix-loop-helix (bHLH) family of proteins. It is known to form a dimer with Ino2p, which regulates phospholipid biosynthetic genes. Mammalian bHLH proteins have been shown to form multiple dimer combinations. However, this flexibility in dimerization had not been documented for yeast bHLH proteins. Using the yeast two-hybrid assay and a biochemical assay we show that Ino4p dimerizes with the Pho4p, Rtg1p, Rtg3p and Sgc1p bHLH proteins. Screening a yeast cDNA library identified three additional proteins that interact with Ino4p: Bck2p, YLR422W and YNR064C. The interaction with Bck2p prompted us to examine if any of the Bck2p-associated functions affect expression of phospholipid biosynthetic genes. We found that hyperosmotic growth conditions altered the growth phase regulation of a phospholipid biosynthetic gene, CHO1. There are two recent reports of initial whole genome yeast two-hybrid interactions. Interestingly, one of these reports identified five proteins that interact with Ino4p: Ino2p, Hcs1p, Apl2p, YMR317W and YNL279W. Ino2p is the only protein in common with the data presented here. Our finding that Ino4p interacts with five bHLH proteins suggests that Ino4p is likely to be a central player in the coordination of multiple biological processes.
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Affiliation(s)
- K A Robinson
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
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Miller MR, McNamara RL, Segal JB, Kim N, Robinson KA, Goodman SN, Powe NR, Bass EB. Efficacy of agents for pharmacologic conversion of atrial fibrillation and subsequent maintenance of sinus rhythm: a meta-analysis of clinical trials. J Fam Pract 2000; 49:1033-1046. [PMID: 11093570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
CONTEXT Physicians have little evidentiary guidance for pharmacologic agent selection for atrial fibrillation (AF). OBJECTIVE To assess antiarrhythmic agent efficacy for AF conversion and subsequent maintenance of sinus rhythm (MSR). DATA SOURCE We searched the clinical trial database of the Cochrane Collaboration and MEDLINE encompassing literature from 1948 to May 1998. STUDY SELECTION We selected 36 (28%) articles eligible as randomized trials of nonpostoperative AF conversion or MSR in adults. DATA EXTRACTION Study quality; rates of conversion, MSR, and adverse events were extracted. DATA SYNTHESIS Compared with control treatment (placebo, verapamil, diltiazem, or digoxin), the odds ratio (OR) for conversion was greatest for ibutilide/dofetilide (OR=29.1; 95% confidence interval [CI], 9.8-86.1) and flecainide (OR=24.7; 95% CI, 9.0-68.3). Less strong but conclusive evidence existed for propafenone (OR=4.6; 95% CI, 2.6-8.2). Quinidine (OR=2.9; 95% CI, 1.2-7.0) had moderate evidence of efficacy for conversion. Disopyramide (OR=7.0; 95% CI, 0.3-153.0) and amiodarone (OR=5.7; 95% CI, 1.0-33.4) had suggestive evidence of efficacy. Sotalol (OR=0.4; 95% CI, 0.0-3.0) had suggestive evidence of negative efficacy. For MSR, strong evidence of efficacy existed for quinidine (OR=4.1; 95% CI, 2.5-6.7), disopyramide (OR=3.4; CI, 1.6-7.1), flecainide (OR=3.1; 95% CI, 1.5-6.2), propafenone (OR=3.7; 95% CI, 2.4-5.7), and sotalol (OR=7.1; 95% CI, 3.8-13.4). The only amiodarone data, from comparison with disopyramide, provided moderate evidence of efficacy for MSR. No trial evaluated procainamide. Direct agent comparisons and adverse event data were limited. CONCLUSIONS Although multiple antiarrhythmic agents had strong evidence of efficacy compared with control treatment for MSR, ibutilide/dofetilide and flecainide had particularly strong evidence of efficacy compared with control treatment for AF conversion. There is sparse and inconclusive evidence on direct agent comparisons and adverse event rates. Obtaining information regarding these relative efficacies should be a research priority.
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Affiliation(s)
- M R Miller
- Division of Pediatric Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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26
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Robinson KA. Doses of olanzapine, risperidone, and haloperidol used in clinical practice: results of a prospective pharmacoepidemiologic study. Clin Ther 2000; 22:1375-6. [PMID: 11117662 DOI: 10.1016/s0149-2918(00)83035-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Schein OD, Friedman DS, Fleisher LA, Lubomski LH, Magaziner J, Sprintz M, Kempen J, Reeves SW, Robinson KA, Bass EB. Anesthesia management during cataract surgery. Evid Rep Technol Assess (Summ) 2000:1-3. [PMID: 10967743 PMCID: PMC4781079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
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Abstract
Sustained hyperglycemia induces insulin resistance, but the mechanism is still incompletely understood. Glucosamine (GlcN) has been extensively used to model the role of the hexosamine synthesis pathway (HSP) in glucose-induced insulin resistance. 3T3-L1 adipocytes were preincubated for 18 h in media +/- 0.6 nmol/l insulin containing either low glucose (5 mmol/l), low glucose plus GlcN (0.1-2.5 mmol/l), or high glucose (25 mmol/l). Basal and acute insulin-stimulated (100 nmol/l) glucose transport was measured after re-equilibration in serum and insulin-free media. Preincubation with high glucose or GlcN (1-2.5 mmol/l) inhibited basal and acute insulin-stimulated glucose transport only if insulin was present during preincubation. However, only preincubation with GlcN plus insulin inhibited insulin-stimulated GLUT4 translocation. GLUT4 and GLUT1 protein expression were not affected. GlcN (2.5 mmol/l) increased cellular UDP-N-acetylhexosamines (UDP-HexNAc) by 400 and 900% without or with insulin, respectively. High glucose plus insulin increased UDP-HexNAc by 30%. GlcN depleted UDP-hexoses, whereas high glucose plus insulin increased them. Preincubation with 0.5 mmol/l GlcN plus insulin maximally increased UDP-HexNAc without affecting insulin-stimulated or basal glucose transport. GlcN plus insulin (but not high glucose plus insulin) caused marked GlcN dose-dependent accumulation of GlcN-6-phosphate, which correlated with insulin resistance of glucose transport (r = 0.935). GlcN plus insulin (but not high glucose plus insulin) decreased ATP (10-30%) and UTP (>50%). GTP was not measured, but GDP increased. Neither high glucose plus insulin nor GlcN plus insulin prevented acute insulin stimulation (approximately 20-fold) of insulin receptor substrate 1-associated phosphatidylinositol (PI)-3 kinase. We have come to the following conclusions. 1) Chronic exposure to high glucose or GlcN in the presence of low insulin caused insulin resistance of glucose transport by different mechanisms. 2) GlcN inhibited GLUT4 translocation, whereas high glucose impaired GLUT4 "intrinsic activity" or membrane intercalation. 3) Both agents may act distally to PI-3 kinase. 4) GlcN has metabolic effects not shared by high glucose. GlcN may not model HSP appropriately, at least in 3T3-L1 adipocytes.
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Affiliation(s)
- B A Nelson
- Department of Medicine, Medical University of South Carolina, Charleston 29425, USA
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Abstract
Oxidative stress has traditionally been viewed as a stochastic process of cell damage resulting from aerobic metabolism, and antioxidants have been viewed simply as free radical scavengers. Only recently has it been recognized that reactive oxygen species (ROS) are widely used as second messengers to propagate proinflammatory or growth-stimulatory signals. With this knowledge has come the corollary realization that oxidative stress and chronic inflammation are related, perhaps inseparable phenomena. New pharmacological strategies aimed at supplementing antioxidant defense systems while antagonizing redox-sensitive signal transduction may allow improved clinical management of chronic inflammatory or degenerative conditions, including Alzheimer's disease. Introduction of antioxidant therapies into mainstream medicine is possible and promising, but will require significant advances in basic cell biology, pharmacology, and clinical bioanalysis.
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Affiliation(s)
- K Hensley
- Free Radical Biology and Aging Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
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30
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McNamara RL, Bass EB, Miller MR, Segal JB, Goodman SN, Kim NL, Robinson KA, Powe NR. Management of new onset atrial fibrillation. Evid Rep Technol Assess (Summ) 2000:1-7. [PMID: 11471248 PMCID: PMC4781222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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31
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Abstract
In Saccharomyces cerevisiae, the phospholipid biosynthetic genes are transcriptionally regulated in response to inositol and choline. This regulation requires the transcriptional activator proteins Ino4p and Ino2p, which form a heterodimer that binds to the UAS(INO) element. We have previously shown that the promoters of the INO4 and INO2 genes are among the weakest promoters characterized in yeast. Because little is known about the promoters of weakly expressed yeast genes, we report here the analysis of the constitutive INO4 promoter. Promoter deletion constructs scanning 1,000 bp upstream of the INO4 gene identified a small region (-58 to -46) that is absolutely required for expression. S1 nuclease mapping shows that this region contains the transcription start sites for the INO4 gene. An additional element (-114 to -86) modestly enhances INO4 promoter activity (fivefold). Thus, the region required for INO4 transcription is limited to 68 bp. These studies also found that INO4 gene expression is not autoregulated by Ino2p and Ino4p, despite the presence of a putative UAS(INO) element in the INO4 promoter. We further report that the INO4 steady-state transcript levels and Ino4p levels are regulated twofold in response to inositol and choline, suggesting a posttranscriptional mechanism of regulation.
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Affiliation(s)
- K A Robinson
- Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202, USA
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32
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Verheye S, Markou CP, Salame MY, Wan B, King SB, Robinson KA, Chronos NA, Hanson SR. Reduced thrombus formation by hyaluronic acid coating of endovascular devices. Arterioscler Thromb Vasc Biol 2000; 20:1168-72. [PMID: 10764689 DOI: 10.1161/01.atv.20.4.1168] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Biocompatible stent coatings may alleviate problems of increased (sub)acute thrombosis after stent implantation. Hyaluronic acid (HA), a ubiquitous, nonsulfated glycosaminoglycan, inhibits platelet adhesion and aggregation and prolongs bleeding when administered systemically. However, the effects of immobilized HA for reducing stent platelet deposition in vivo are unknown. We therefore quantified the antithrombotic effects of coating stainless steel stents and tubes with HA using an established baboon thrombosis model under physiologically relevant blood flow conditions. HA-coated and uncoated (control) stents (3.5 mm in diameter, n=32) and stainless steel tubes (4.0 mm in diameter, n=18) were deployed into exteriorized arteriovenous shunts of conscious, nonanticoagulated baboons. Accumulation of (111)In-radiolabeled platelets was quantified by continuous gamma-camera imaging during a 2-hour blood exposure period. HA coating resulted in a significant reduction in platelet deposition in long (4 cm) tubes (0.24+/-0.15 x 10(9) versus 6.12+/-0.49 x 10(9) platelets; P<0.03), short (2 cm) stainless steel tubes (0.18+/-0.06 x 10(9) versus 3.03+/-0.56 x 10(9) platelets; P<0.008), and stents (0.82+/-0.20 x 10(9) versus 1.83+/-0. 23 x 10(9) platelets; P<0.02) compared with uncoated control devices. Thus, HA coating reduces platelet thrombus formation on stainless steel stents and tubes in primate thrombosis models. These results indicate that immobilized HA may represent an attractive strategy for improving the thromboresistance of endovascular devices.
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Affiliation(s)
- S Verheye
- Division of Molecular Medicine, Yerkes Regional Primate Research Center, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
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Robinson KA, Lopes JM. SURVEY AND SUMMARY: Saccharomyces cerevisiae basic helix-loop-helix proteins regulate diverse biological processes. Nucleic Acids Res 2000; 28:1499-505. [PMID: 10710415 PMCID: PMC102793 DOI: 10.1093/nar/28.7.1499] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/1999] [Revised: 02/14/2000] [Accepted: 02/14/2000] [Indexed: 01/07/2023] Open
Abstract
Basic helix-loop-helix (bHLH) proteins are among the most well studied and functionally important regulatory proteins in all eukaryotes. The HLH domain dictates dimerization to create homo- and heterodimers. Dimerization juxtaposes the basic regions of the two monomers to create a DNA interaction surface that recognizes the consensus sequence called the E-box, 5'-CANNTG-3'. Several bHLH proteins have been identified in the yeast Saccharomyces cerevisiae using traditional genetic methodologies. These proteins regulate diverse biological pathways. The completed sequence of the yeast genome, combined with novel methodologies allowing whole-genome expression studies, now offers a unique opportunity to study the function of these bHLH proteins. It is the purpose of this review to summarize the current knowledge of bHLH protein function in yeast.
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Affiliation(s)
- K A Robinson
- Department of Molecular and Cellular Biochemistry, Loyola University of Chicago, Maywood, IL 60153, USA
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Affiliation(s)
- S P Gabbita
- Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, Oklahoma, 73104, USA
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Ishiwata S, Verheye S, Robinson KA, Salame MY, de Leon H, King SB, Chronos NA. Inhibition of neointima formation by tranilast in pig coronary arteries after balloon angioplasty and stent implantation. J Am Coll Cardiol 2000; 35:1331-7. [PMID: 10758977 DOI: 10.1016/s0735-1097(00)00528-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES We evaluated the effect of orally administered tranilast, N-(3,4-dimethoxycinnamoyl) anthranilic acid, on histologic and histomorphometric changes after angioplasty or stent implantation in pig coronary arteries. BACKGROUND Tranilast, which has antikeloid and antiallergic properties and therefore may modulate the fibrotic and inflammatory tissue responses to angioplasty and stenting, has been shown to inhibit angiographic restenosis in small clinical trials. However, its effect on histomorphometric changes in coronary arteries after angioplasty and stenting is unknown. METHODS Following initial pharmacokinetic studies in two pigs to determine desirable plasma levels of orally administered tranilast, 36 crossbred juvenile pigs were randomized to placebo or tranilast before undergoing balloon angioplasty in both the left anterior descending and left circumflex plus stent implantation in the right coronary artery. Oral tranilast was administered at 3 g/day starting 3 days before coronary injury and continued for 28 days until euthanasia. Injured vessels were harvested and sections analyzed by computer-assisted microscopic planimetry. RESULTS In balloon-injured vessels, tranilast was associated with a 37% reduction in neointimal area normalized to fracture length (0.47 +/- 0.01 vs. 0.74 +/- 0.03 mm; p < 0.001) and a 23% reduction in adventitial area normalized to vessel size (0.43 +/- 0.02 vs. 0.56 +/- 0.03; p = 0.003). In stented arteries, neointimal area normalized to injury score was 32% lower in the tranilast-treated group compared to control (1.94 +/- 0.17 vs. 2.86 +/- 0.29; p = 0.01). CONCLUSIONS In pig coronary arteries, tranilast was associated with a reduction in neointima formation and adventitial reaction after balloon injury. In stented vessels, tranilast was associated with a reduction in neointima formation normalized to injury score.
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MESH Headings
- Administration, Oral
- Angioplasty, Balloon, Coronary/adverse effects
- Angioplasty, Balloon, Coronary/instrumentation
- Animals
- Anti-Allergic Agents/blood
- Anti-Allergic Agents/pharmacokinetics
- Anti-Allergic Agents/therapeutic use
- Anti-Inflammatory Agents, Non-Steroidal/blood
- Anti-Inflammatory Agents, Non-Steroidal/pharmacokinetics
- Anti-Inflammatory Agents, Non-Steroidal/therapeutic use
- Coronary Disease/blood
- Coronary Disease/immunology
- Coronary Disease/pathology
- Coronary Disease/therapy
- Coronary Vessels/injuries
- Disease Models, Animal
- Drug Evaluation, Preclinical
- Female
- Fibrosis
- Inflammation
- Male
- Random Allocation
- Recurrence
- Stents/adverse effects
- Swine
- Time Factors
- Tunica Intima/injuries
- Wound Healing/drug effects
- Wounds and Injuries/immunology
- Wounds and Injuries/pathology
- Wounds and Injuries/prevention & control
- ortho-Aminobenzoates/blood
- ortho-Aminobenzoates/pharmacokinetics
- ortho-Aminobenzoates/therapeutic use
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Affiliation(s)
- S Ishiwata
- Andreas Gruentzig Cardiovascular Center, Department of Medicine (cardiology), Emory University School of Medicine, Atlanta, Georgia, USA
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36
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Salame MY, Verheye S, Mulkey SP, Chronos NA, King SB, Crocker IR, Robinson KA. The effect of endovascular irradiation on platelet recruitment at sites of balloon angioplasty in pig coronary arteries. Circulation 2000; 101:1087-90. [PMID: 10715252 DOI: 10.1161/01.cir.101.10.1087] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Endovascular irradiation (EI) inhibits balloon-induced neointima formation in animals and is now in clinical trials for restenosis prevention. However, little is known of the effect of EI on vessel thrombogenicity due to delayed arterial healing. We investigated EI effects on platelet recruitment in pig coronary arteries. METHODS AND RESULTS EI was performed using (90)Sr/Y at 0 Gray (Gy), 15Gy, or 30Gy at 2 mm after balloon overstretch injury. At 1 day, 1 week, and 1 month, platelet recruitment and thrombus formation were assessed using autologous (111)In-oxine-platelet labeling and light and scanning electron microscopy. In balloon-injured nonirradiated vessels, there was complete reendothelialization at 1 month, and platelet recruitment was similar to normal uninjured arteries. In irradiated vessels, scanning electron microscopy showed incomplete reendothelialization at 1 month, and these areas demonstrated attachment of activated platelets. Light microscopy of irradiated coronaries showed adherent partially organized thrombi and incomplete resolution of intramural hemorrhages. There was a significant increase in platelet recruitment at 1 month in arteries receiving EI at 15Gy (5.1+/-2. 8x10(6), P=0.02) or 30Gy (12.5+/-9.9x10(6), P=0.005) compared with nonirradiated controls (2.7+/-1.5x10(6)); 30Gy was also higher than 15Gy (P=0.05). Platelet recruitment was also increased for 30Gy compared with control at 1 day. CONCLUSIONS Endovascular irradiation at 15Gy or 30Gy after balloon angioplasty results in incomplete endothelial recovery, impaired resolution of intramural hemorrhage, and a dose-dependent increase in platelet recruitment at 1 month.
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Affiliation(s)
- M Y Salame
- Andreas Gruentzig Cardiovascular Center, Department of Medicine (Cardiology), Emory University School of Medicine, Atlanta, GA, USA
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37
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Hensley K, Robinson KA, Pye QN, Floyd RA, Cheng I, Garland WA, Irwin I. CPI-1189 inhibits interleukin 1beta-induced p38-mitogen-activated protein kinase phosphorylation: an explanation for its neuroprotective properties? Neurosci Lett 2000; 281:179-82. [PMID: 10704772 DOI: 10.1016/s0304-3940(00)00861-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The p38 mitogen-activated protein kinase (p38-MAPK) is a central enzyme in one of the major protein kinase cascades that regulate proapoptotic and proinflammatory signal transduction. p38-MAPK is activated by receptor/ligand recognition events or by exposure to extracellular stressors, including oxidative stress. Activation of p38-MAPK is affected by dual phosphorylation on a specific inhibitory domain. Dual phosphorylation causes a structural change in the p38-MAPK enzyme which allows binding of ATP and target substrate. Agents which block ATP docking to phosphoactivated p38-MAPK are being investigated for treatment of inflammatory diseases and neurodegenerative pathologies. An alternative strategy for p38-MAPK antagonism would be the inhibition of p38-MAPK phosphoactivation. We now report potent inhibition of p38-MAPK phosphorylation by a synthetic benzamide (CPI-1189) which displays protective action against tumor necrosis factor-alpha (TNFalpha)-induced neurodegeneration. In primary astrocytes treated with interleukin 1beta (IL1beta), CPI-1189 inhibits p38-MAPK phosphorylation at concentrations of 10 nM or less. While the precise molecular target of CPI-1189 remains unknown, these findings suggest a novel mechanism for the neuroprotective properties of the compound. These findings also indicate that antagonism of the p38-MAPK may be achieved through pharmacological inhibition of p38-MAPK phosphorylation, a strategy that is conceptually distinct from direct inhibition of ATP binding to the active enzyme.
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Affiliation(s)
- K Hensley
- Free Radical Biology and Aging Research Program, Oklahoma Medical Research Foundation, Oklahoma 73104, USA.
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Gazdag AC, Wetter TJ, Davidson RT, Robinson KA, Buse MG, Yee AJ, Turcotte LP, Cartee GD. Lower calorie intake enhances muscle insulin action and reduces hexosamine levels. Am J Physiol Regul Integr Comp Physiol 2000; 278:R504-12. [PMID: 10666154 DOI: 10.1152/ajpregu.2000.278.2.r504] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies have demonstrated enhanced insulin sensitivity in calorie-restricted [CR, fed 60% ad libitum (AL) one time daily] compared with AL-fed rats. To evaluate the effects of reduced food intake, independent of temporal differences in consumption, we studied AL (unlimited food access)-fed and CR (fed one time daily) rats along with groups temporally matched for feeding [fed 3 meals (M) daily]: MAL and MCR, eating 100 and 60% of AL intake, respectively. Insulin-stimulated glucose transport by isolated muscle was increased in MCR and CR vs. AL and MAL; there was no significant difference for MCR vs. CR or MAL vs. AL. Intramuscular triglyceride concentration, which is inversely related to insulin sensitivity in some conditions, did not differ among groups. Muscle concentration of UDP-N-acetylhexosamines [end products of the hexosamine biosynthetic pathway (HBP)] was lower in MCR vs. MAL despite unaltered glutamine-fructose-6-phosphate aminotransferase activity (rate-limiting enzyme for HBP). These results indicate that the CR-induced increase in insulin-stimulated glucose transport in muscle is attributable to an altered amount, not timing, of food intake and is independent of lower triglyceride concentration. They further suggest that enhanced insulin action might involve changes in HBP.
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Affiliation(s)
- A C Gazdag
- Biodynamics Laboratory, University of Wisconsin, Madison, Wisconsin 53706, USA
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Segal JB, McNamara RL, Miller MR, Kim N, Goodman SN, Powe NR, Robinson KA, Bass EB. Prevention of thromboembolism in atrial fibrillation. A meta-analysis of trials of anticoagulants and antiplatelet drugs. J Gen Intern Med 2000; 15:56-67. [PMID: 10632835 PMCID: PMC1495320 DOI: 10.1046/j.1525-1497.2000.04329.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Appropriate use of drugs to prevent thromboembolism in patients with atrial fibrillation (AF) involves comparing the patient's risk of stroke and risk of hemorrhage. This review summarizes the evidence regarding the efficacy of these medications. METHODS We conducted a meta-analysis of randomized controlled trials of drugs used to prevent thromboembolism in adults with nonpostoperative AF. Articles were identified through the Cochrane Collaboration's CENTRAL database and MEDLINE until May 1998. MAIN RESULTS Eleven articles met criteria for inclusion in this review. Warfarin was more efficacious than placebo for primary stroke prevention (aggregate odds ratio [OR] of stroke = 0.30, 95% confidence interval [CI] 0.19, 0.48), with moderate evidence of more major bleeding (OR 1.90; 95% CI 0.89, 4.04). Aspirin was inconclusively more efficacious than placebo for stroke prevention (OR 0.56, 95% CI 0.19, 1.65), with inconclusive evidence regarding more major bleeds (OR 0.81, 95% CI 0.37, 1.77). For primary prevention, assuming a baseline risk of 45 strokes per 1,000 patient-years, warfarin could prevent 30 strokes at the expense of only 6 additional major bleeds. Aspirin could prevent 17 strokes, without increasing major hemorrhage. In direct comparison, there was evidence suggesting fewer strokes among patients on warfarin than among patients on aspirin (aggregate OR 0.64, 95% CI 0.43, 0.96), with only suggestive evidence for more major hemorrhage (OR 1.60, 95% CI 0.77,3.35). However, in younger patients, with a mean age of 65 years, the absolute reduction in stroke rate with warfarin compared with aspirin was low (5.5 per 1,000 person-years) compared with an older group (15 per 1,000 person-years). CONCLUSION In general, the evidence strongly supports warfarin for patients with AF at average or greater risk of stroke. Aspirin may prove to be useful in subgroups with a low risk of stroke, although this is not definitively supported by the evidence.
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Affiliation(s)
- J B Segal
- Division of General Internal Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Verheye S, Salame MY, Robinson KA, Post MJ, Carrozza JP, Baim DS, Sigwart U, King SB, Chronos NA. Short- and long-term histopathologic evaluation of stenting using a self-expanding nitinol stent in pig carotid and iliac arteries. Catheter Cardiovasc Interv 1999; 48:316-23. [PMID: 10525238 DOI: 10.1002/(sici)1522-726x(199911)48:3<316::aid-ccd19>3.0.co;2-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Stenting is increasingly being used to treat carotid artery disease. However, complications including distal embolization, stent thrombosis, stent collapse from external compression, the need for high-pressure inflation with increased neointimal response, or balloon rupture during stent expansion and stent loss are all potential problems and of concern. To address each of these specific concerns, a new stent was designed, which is self-expandable, made of nitinol, with temperature-dependent superelastic properties, and with high vessel wall surface coverage. Since this device has a number of novel characteristics, we aimed to assess the short- and long-term histopathologic response in pig carotid and iliac arteries. Single stents were deployed in pig carotid and iliac arteries after overstretch balloon injury. Angiograms were performed pre- and poststenting and prior to sacrifice. Intravascular ultrasound was used before implantation to determine vessel size. Vessels were examined histologically at 1 month (n = 6) and 6 months (n = 6) for morphometric analysis, hemorrhage and thrombus, endothelialization, and inflammatory and fibrotic responses. There was a 100% angiographic success rate at implantation. In one case, it was determined histologically that a single stent was implanted in a dissection plane of a pig's left iliac artery and was occluded by organized thrombus, with the true lumen being patent. At 6-month follow-up, this was the only evidence of a single stent occlusion, with flow adjacent to the stent in the true lumen. In the other vessels, the stents showed good vessel wall-stent apposition and the lumens were patent with a concentric and thin neointima. Inflammatory cells were rare and there were no mural thrombi. Coverage of the vessel wall by endothelial-like cells was complete at 1 month. The novel nitinol EndoStent appears to have favorable biocompatibility with minimal thrombus deposition or inflammatory response, and its use is feasible for clinical application in carotid and iliac arteries.
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Affiliation(s)
- S Verheye
- Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia, USA
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Marijianowski MM, Crocker IR, Styles T, Forestner DM, Waksman R, Cipolla GD, King SB, Robinson KA. Fibrocellular tissue responses to endovascular and external beam irradiation in the porcine model of restenosis. Int J Radiat Oncol Biol Phys 1999; 44:633-41. [PMID: 10348294 DOI: 10.1016/s0360-3016(99)00038-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE Endovascular radiation has reduced postangioplasty restenosis in preclinical and early clinical studies. External radiation treatment may have advantages over endovascular therapy. We examined vascular and perivascular tissue responses to endovascular and external irradiation in pig coronary arteries. METHODS AND MATERIALS Ninety-one animals received endovascular or external radiation following balloon injury and were sacrificed at 14, 30, or 180 days. Injured segments of coronary vessels including perivascular and myocardial tissues were evaluated with histochemistry. RESULTS Endovascular radiation was associated with delayed arterial wound healing as late as 6 months, evidenced by paucity of smooth muscle alpha-actin in neointimal cells compared to control. External treatment was associated with increased collagen in neointima and adventitia, and focal interstitial necrosis in adjacent myocardium. CONCLUSIONS These investigations showed whole-heart 14 Gy external radiation treatment following coronary injury exacerbated certain aspects of arterial healing. In addition focal myocardial necrosis and fibrosis was observed following external but not endovascular irradiation. Endovascular radiation has some advantages over external irradiation; however the persistence of a synthetic smooth muscle cell phenotype in the neointima at 6 months suggests ionizing radiation in general may have profound effects on vessel architecture over the long term.
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Affiliation(s)
- M M Marijianowski
- The Andreas Gruentzig Cardiovascular Center, Department of Medicine (Cardiology), Emory University School of Medicine, Atlanta, GA, USA
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Robinson KA, Stewart CA, Pye Q, Floyd RA, Hensley K. Basal protein phosphorylation is decreased and phosphatase activity increased by an antioxidant and a free radical trap in primary rat glia. Arch Biochem Biophys 1999; 365:211-5. [PMID: 10328814 DOI: 10.1006/abbi.1999.1178] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reversible protein phosphorylation regulates a wide array of cellular functions. Cells respond to cytokines and various stressors via phosphorylation and thus activation of one or more of the mitogen-activated protein kinase (MAPK) pathways. Involvement of these signal transduction pathways has been implicated in numerous pathologies, including inflammation. Using a primary glia cell culture, we show here that the antioxidant N-acetylcysteine (NAC) and the nitrone-based free radical trap, alpha-phenyl-N-tert-butyl nitrone (PBN), reduce total basal protein phosphorylation in a concentration-dependent manner as assessed by phosphotyrosine analysis and by [gamma-32P]ATP transfer radioassay. In addition we show that NAC inhibits H2O2-induced phosphatase inactivation in glia cell lysate. The PBN- and NAC-induced reduction in protein phosphorylation is accompanied by an increase in phosphatase activity, suggesting that PBN and NAC reduce protein phosphorylation by globally augmenting oxidant-sensitive phosphatase activities. These results partly explain why certain antioxidants also possess anti-inflammatory actions.
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Affiliation(s)
- K A Robinson
- Free Radical Biology and Aging Research Program, Oklahoma Medical Research Foundation, 825 Northeast 13th Street, Oklahoma City, Oklahoma, 73104, USA
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Apkarian RP, Caran KL, Robinson KA. Topographic Imaging of Chromium-Coated Frozen-Hydrated Cell and Macromolecular Complexes by In-Lens Field Emission Scanning Electron Microscopy. Microsc Microanal 1999; 5:197-207. [PMID: 10383992 DOI: 10.1017/s1431927699000148] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
: An in-lens Schottky field emission scanning electron microscope (SEM) combined with a transmission electron microscope (TEM)-type cold-stage and a chromium (Cr) sputter-coating system was developed to rapidly prepare and cryo-image biological specimens to attain accurate nanometer-level structural information. High-resolution topographic images at high primary magnification (>/=200,000x) were digitally recorded with very short dwell times and without beam damage. Plunge freezing in ethane, followed by fracturing, Cr coating, and in-lens cryo-high-resolution scanning electron microscope (HRSEM) imaging directly revealed macromolecular features of yeast cells, platelets, and cell-free elastin analogues. The "vitreous" nature of bulk water in its solid state appeared featureless in cryo-HRSEM images, suggesting that if ice crystals were present they would be </=2-3 nm (the approximate instrument resolution on cryo-specimens). Compared to technically difficult and indirect freeze-fracture TEM replicas, cryo-HRSEM samples are fully hydrated, unfixed, noncryoprotected specimens immersed in featureless ice. The time necessary to cryo-immobilize the specimen and record the image is <3 hr. The hexagonal arrays of intramembrane particles on the protoplasmic face of yeast cells and differences in surface morphology between thrombin-stimulated and quiescent platelets were assessed. A clear interface line between collapsed elastin fibril lacework and vitreous lakes was commonly observed. These experiments demonstrate the feasibility of this technique to rapidly evaluate macromolecular features in cryofixed cells and cell-free systems.
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Affiliation(s)
- RP Apkarian
- Department of Chemistry, Integrated Microscopy and Microanalytical Facility, Emory University, Atlanta, GA 30322
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Hensley K, Floyd RA, Zheng NY, Nael R, Robinson KA, Nguyen X, Pye QN, Stewart CA, Geddes J, Markesbery WR, Patel E, Johnson GV, Bing G. p38 kinase is activated in the Alzheimer's disease brain. J Neurochem 1999; 72:2053-8. [PMID: 10217284 DOI: 10.1046/j.1471-4159.1999.0722053.x] [Citation(s) in RCA: 274] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The p38 mitogen-activated protein kinase is a stress-activated enzyme responsible for transducing inflammatory signals and initiating apoptosis. In the Alzheimer's disease (AD) brain, increased levels of phosphorylated (active) p38 were detected relative to age-matched normal brain. Intense phospho-p38 immunoreactivity was associated with neuritic plaques, neuropil threads, and neurofibrillary tangle-bearing neurons. The antibody against phosphorylated p38 recognized many of the same structures as an antibody against aberrantly phosphorylated, paired helical filament (PHF) tau, although PHF-positive tau did not cross-react with the phospho-p38 antibody. These findings suggest a neuroinflammatory mechanism in the AD brain, in which aberrant protein phosphorylation affects signal transduction elements, including the p38 kinase cascade, as well as cytoskeletal components.
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Affiliation(s)
- K Hensley
- Free Radical Biology and Aging Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
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Stewart CA, Hyam K, Wallis G, Sang H, Robinson KA, Floyd RA, Kotake Y, Hensley K. Phenyl-N-tert-butylnitrone demonstrates broad-spectrum inhibition of apoptosis-associated gene expression in endotoxin-treated rats. Arch Biochem Biophys 1999; 365:71-4. [PMID: 10222040 DOI: 10.1006/abbi.1999.1159] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Systemic exposure to gram-negative bacterial substances such as lipopolysaccharide (LPS, or endotoxin) induces an uncontrolled, massive inflammatory reaction which culminates in multiple system organ failure and death. Septic shock often does not respond to corticosteroids; however, certain low-molecular-weight antioxidant compounds have been discovered to possess potent anti-inflammatory action, and some of these novel compounds can rescue animals from experimentally induced septic shock. Phenyl-N-tert-butylnitrone (PBN) is the archetype of the nitrone class of antioxidants which we have previously shown to suppress LPS-induced cytokine biosynthesis in vivo. Using a multiprobe ribonuclease protection assay, we now demonstrate the ability of PBN to suppress proapoptotic gene expression in the LPS-induced model of endotoxic shock. The broad-spectrum gene-suppressive affects of PBN are discussed in the context of inflammatory signal transduction and models are proposed to explain why certain antioxidants may also possess anti-inflammatory and antiapoptotic properties.
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Affiliation(s)
- C A Stewart
- Free Radical Biology and Aging Research Program, Oklahoma Medical Research Foundation, 825 Northeast 13th Street, Oklahoma City, Oklahoma 73104, USA
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Robinson KA, Stewart CA, Pye QN, Nguyen X, Kenney L, Salzman S, Floyd RA, Hensley K. Redox-sensitive protein phosphatase activity regulates the phosphorylation state of p38 protein kinase in primary astrocyte culture. J Neurosci Res 1999; 55:724-32. [PMID: 10220113 DOI: 10.1002/(sici)1097-4547(19990315)55:6<724::aid-jnr7>3.0.co;2-9] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Reactive oxygen species (ROS) have been implicated as second messengers that activate protein kinase cascades, although the means by which ROS regulate signal transduction remains unclear. In the present study, we show that interleukin 1beta (IL1beta), H2O2, and sorbitol-induced hyperosmolarity mediate a 5- to 10-fold increase in phosphorylation (activation) of the p38 protein kinase in rat primary glial cells as measured by analyses of Western blots using an antibody directed against the dually phosphorylated (active) p38. Additionally, IL1beta was found to elicit H2O2 synthesis in these cells. Concurrent with p38 phosphorylation, all three stimulation paradigms caused an inhibition of protein phosphatase activity. Phenyl-tert-butyl nitrone (PBN), a nitrone-based free radical trap and N-acetyl-cysteine (NAC), a thiol reducing agent, were examined for their effects on the phosphorylation of p38 as well as phosphatase activity. Pretreatment of cells with either PBN or NAC at 1.0 mM suppressed IL1beta H2O2, and sorbitol-mediated activation of p38 and significantly increased phosphatase activity. These data suggest that ROS, particularly H2O2, are used as second messenger substances that activate p38 in part via the transient inactivation of regulatory protein phosphatases.
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Affiliation(s)
- K A Robinson
- Free Radical Biology and Aging Research Program, Oklahoma Medical Research Foundation, Oklahoma City, USA
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Jafari HS, Adams WG, Robinson KA, Plikaytis BD, Wenger JD. Efficacy of Haemophilus influenzae type b conjugate vaccines and persistence of disease in disadvantaged populations. The Haemophilus Influenzae Study Group. Am J Public Health 1999; 89:364-8. [PMID: 10076486 PMCID: PMC1508617 DOI: 10.2105/ajph.89.3.364] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES The purpose of this study was to evaluate the effectiveness of Haemophilus influenzae type b (Hib) conjugate vaccines among children aged 2 to 18 months and to determine risk factors for invasive Hib disease during a period of declining incidence (1991-1994). METHODS A prospective population-based case-control study was conducted in a multistate US population of 15.5 million. A laboratory-based active surveillance system was used for case detection. RESULTS In a multivariate analysis, having a single-parent mother (odds ratio [OR] = 4.3, 95% confidence interval [CI] = 1.2, 14.8) and household crowding (OR = 3.5, 95% CI = 1.03, 11.7) were risk factors for Hib disease independent of vaccination status. After adjustment for these risk factors, the protective efficacy of 2 or more Hib vaccine doses was 86% (95% CI = 16%, 98%). Among undervaccinated subjects, living with a smoker (P = .02) and several indicators of lower socioeconomic status were risk factors for Hib disease. CONCLUSIONS Hib disease still occurs at low levels in the United States, predominantly in socioeconomically disadvantaged populations. Low immunization coverage may facilitate continuing transmission of Hib. Special efforts to achieve complete and timely immunization in disadvantaged populations are needed.
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Affiliation(s)
- H S Jafari
- Childhood and Respiratory Diseases Branch, National Center for Infectious Diseases, Atlanta, Ga., USA
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Abstract
When the hematopoietic growth factor granulocyte-macrophage colony-stimulating factor was incubated with neutrophils adherent to plastic tissue culture plates or plates coated with extracellular matrix proteins, a rapid (3 min) but transient formation of phosphatidic acid was observed. This stimulation was dependent on the dose of GM-CSF, with an EC50 of 140 pM, and was further enhanced (up to 350%) with the PA phosphatase inhibitor propranolol in a dose-dependent manner. Conversely, GM-CSF was unable to trigger any PA formation in neutrophils maintained in suspension, even in the presence of soluble fibronectin. However, GM-CSF did prime the cells for enhanced PA formation in the presence of a secondary stimulus (fMet-Leu-Phe or PAF). GM-CSF also caused a time-dependent stimulation of diacylglycerol formation in adherent, but not suspended, cells and elicited a time-dependent stimulation of phosphatidylethanol formation, with a concomitant decrease in the formation of PA only at early (< 7 min) times. These observations were consistent with a rapid activation of the enzyme phospholipase D in adherent cells stimulated with GM-CSF. Additional data indicated that the source of DAG was PLD coexisting with PLC, especially at later times ( > 7 min) of stimulation with GM-CSF. Finally, the formation of PA and PEt, and to a minor extent, DAG, were inhibited by the protein tyrosine kinase inhibitor erbstatin in conditions in which tyrosine phosphorylation occurred. Taken together the data indicate that GM-CSF rapidly activates PLD in adherent cells, which is responsible for the generation of PA. Thus, PLD activation is an early event in neutrophil signal transduction following exposure of adherent cells to GM-CSF.
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Affiliation(s)
- T S Hayes
- Department of Physiology, Wright State University School of Medicine, Dayton, OH 45435, USA
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Robinson KA, Willi SM, Bingel S, Buse MG. Decreased hexosamine biosynthesis in GH-deficient dwarf rat muscle. reversal with GH, but not IGF-I, therapy. Am J Physiol 1999; 276:E435-42. [PMID: 10070007 DOI: 10.1152/ajpendo.1999.276.3.e435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Enhanced glucose flux via the hexosamine biosynthesis pathway (HNSP) has been implicated in insulin resistance. We measured L-glutamine:D-fructose-6-phosphate amidotransferase activity (GFAT, a rate-limiting enzyme) and concentrations of UDP-N-acetyl hexosamines (UDP-HexNAc, major products of HNSP) in muscle and liver of growth hormone (GH)-deficient male dwarf (dw) rats. All parameters measured, except body weight, were similar in 5-wk-old control and dw rats. Muscle GFAT activity declined progressively with age in controls and dw rats but was consistently 30-60% lower in 8- to 14-wk-old dw rats vs. age-matched controls; UDP-HexNAc concentrations in muscle were concomitantly 30% lower in dw rats vs. controls (P < 0.01). Concentrations of UDP-hexoses, GDP-mannose, and UDP in muscle were similar in control and dw rats. Muscle HNSP activity was similarly diminished in fed and fasted dw rats. In liver, only a small difference in GFAT activity was evident between controls and dw rats, and no differences in UDP-HexNAc concentrations were observed. Treatment with recombinant human GH (rhGH) for 5 days restored UDP-HexNAc to control levels in dw muscles (P < 0.01) and partially restored GFAT activity. Insulin-like growth factor I treatment was ineffective. We conclude that GH participates in HNSP regulation in muscle.
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Affiliation(s)
- K A Robinson
- Division of Endocrinology, Diabetes, and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425-2222, USA
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Berger DS, Fellner SK, Robinson KA, Vlasica K, Godoy IE, Shroff SG. Disparate effects of three types of extracellular acidosis on left ventricular function. Am J Physiol 1999; 276:H582-94. [PMID: 9950860 DOI: 10.1152/ajpheart.1999.276.2.h582] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Effects of acidosis on muscle contractile function have been studied extensively. However, the relative effects of different types of extracellular acidosis on left ventricular (LV) contractile function, especially the temporal features of contraction, have not been investigated in a single model. We constituted perfusion buffers of identical ionic composition, including Ca2+ concentration ([Ca2+]), to mimic physiological control condition (pH 7.40) and three types of acidosis with pH of 7.03: inorganic (IA), respiratory (RA), and lactic (LA). Isolated rabbit hearts (n = 9) were perfused with acidotic buffers chosen at random, each preceded by the control buffer. Under steady-state conditions, instantaneous LV pressure (Pv) and volume (Vv) were recorded for a range of Vv. The results were as follows. 1) LV passive (end-diastolic) elastance increased with IA and RA. However, this increase may not be a direct effect of acidosis; it can be explained on the basis of myocardial turgor. 2) Although LV inotropic state (peak active Pv and elastance) was depressed by all three acidotic buffers, the magnitude of inotropic depression was significantly less for LA. 3) Temporal features of Pv were altered differently. Whereas IA and RA reduced time to peak Pv (tmax) and hastened isovolumic relaxation at a common level of LV wall stress, LA significantly increased tmax and retarded relaxation. These results and a model-based interpretation suggest that cooperative feedback (i.e., force-activation interaction) plays an important role in acidosis-induced changes in LV contractile function. Furthermore, it is proposed that LA-induced responses comprise two components, one due to intracellular acidosis and the other due to pH-independent effects of lactate ions.
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Affiliation(s)
- D S Berger
- Cardiology and Nephrology Sections, Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA
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