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Verplancke V, Dams K, Raman P, Ruttens D, Thiessen S, Baar I, Jacobs R, Lauwers P, Yogeswaran K, Verleden S, Hendriks J, Kwakkel-van Erp J. Use of High Dose Corticosteroids Reversed COVID-19 Associated ARDS in a Patient Listed for Lung Transplantation. J Heart Lung Transplant 2022. [PMCID: PMC8988704 DOI: 10.1016/j.healun.2022.01.1363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Introduction In acute respiratory distress syndrome (ARDS) patients with irreversible lung damage, lung transplantation from a ventilator and/or extracorporeal membrane oxygenation support (ECMO) is feasible. Recently, selection criteria for lung transplant candidates with a COVID-19 associated ARDS have been published. Here, we report the efficacy of high dose corticosteroids as ultimate salvage therapy, despite Meduri scheme attempts, in a patient listed for transplantation. Case Report A 50-year-old female with a medical history of Multiple Sclerosis (relapsing-remitting type under treatment with anti-alpha4 -integrin therapy), was tested positive for COVID-19. She deteriorated and was admitted to the hospital. High flow oxygen and dexamethasone (six milligram daily), were started but unfortunately, she developed a severe ARDS with need for mechanical ventilation and ECMO support. Corticosteroids according to the Meduri scheme and ciprofloxacin were started. Weaning trials were initiated but failed and CT-thorax showed consolidation and presumed fibrosis. After 37 days on ECMO, she was evaluated and listed for bilateral lung transplantation. A corticosteroid pulse therapy of 1000 mg of methylprednisolone IV for three days during antibiotic coverage with piperacillin/tazobactam was started and within three days the clinical condition of the patient improved and she could be weaned from ECMO (51 days of ECMO) and delisted from the lung transplantation waiting list. Nowadays, patient does not require oxygen, is at home and revalidating. Summary Here, we report the efficacy of a regimen with high dose corticosteroids as ultimate salvage therapy, despite Meduri scheme attempts, in a patient listed for transplantation. Corticosteroids are beneficial for immunomodulation and may reduce hyperinflammation. Our trial with administration of high dose corticosteroids pulse therapy in COVID-19 ARDS patients refractory to corticosteroids according to “classical schemes” has been successful and is informative. Further studies, will hopefully further elucidate responders and non-responders to high dose corticosteroid pulse therapy and preferably answer the question if prophylactic use of antibiotics and antifungals (in view of possible complications such as pulmonary aspergillosis and mucormycosis) is prudent in this vulnerable group.
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Nur Hanis Y, Raman P, Premala Devi S, Mohd Khalid KH. The Kuala Pilah cluster cataract study: Accessible eye care reduces cataract blindness. Med J Malaysia 2019; 74:296-299. [PMID: 31424036] [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] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
OBJECTIVE The Ministry of Health introduced the cluster hospital project in Kuala Pilah district in 2016 to allow sharing of resources between the hospitals in the same vicinity. The aim of this study is to compare the demographic profile, prevalence of cataract blindness and low vision among patients who presented for cataract surgery before and after the programme. METHODOLOGY This is a retrospective cohort study of patients who underwent cataract surgery in Kuala Pilah Cluster Hospitals between 2010 and 2017. A total of 2539 records of patients were reviewed. Patients were assigned into two groups: Group 1 (2010-2012)- before the programme (2010-2012) and Group 2 (2015-2017) after the introduction of the programme. RESULTS There was a significant increase in number of cataract cases in the district hospital after the cluster initiative. The mean age of patients undergoing cataract surgery was similar in both groups. The common comorbidities were hypertension (Group 1=57.3%; Group 2=70.8%) and diabetes mellitus (Group 1=40.6%; Group 2=51.1%). In 2010-2012, most of the patients were one eye blind (34.4%), whereas in 2015-2017 majority of patients presented with vision better than 6/18 (43.5%). The proportion of patients with cataract blindness reduced from 6% in 2010-2012 to 4.3% in 2015-2017 (p<0.01). CONCLUSION There is a significant decrease in percentage of patients with cataract blindness and low vision after the introduction of Kuala Pilah Cluster Hospital Program. We believe that that cluster hospital system is effective in improving accessibility to eye care and therefore increases the cataract detection rate.
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Affiliation(s)
- Y Nur Hanis
- Hospital Tuanku Ampuan Najihah, Department of Ophtalmology, Kuala Pilah, Negeri Sembilan, Malaysia.
| | - P Raman
- Hospital Tuanku Ampuan Najihah, Department of Ophtalmology, Kuala Pilah, Negeri Sembilan, Malaysia
| | - S Premala Devi
- Hospital Tuanku Ampuan Najihah, Department of Ophtalmology, Kuala Pilah, Negeri Sembilan, Malaysia
| | - K H Mohd Khalid
- Hospital Tuanku Ampuan Najihah, Department of Ophtalmology, Kuala Pilah, Negeri Sembilan, Malaysia
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Muppala S, Xiao R, Krukovets I, Verbovetsky D, Yendamuri R, Habib N, Raman P, Plow E, Stenina-Adognravi O. Thrombospondin-4 mediates TGF-β-induced angiogenesis. Oncogene 2017; 36:5189-5198. [PMID: 28481870 PMCID: PMC5589494 DOI: 10.1038/onc.2017.140] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 03/24/2017] [Accepted: 04/10/2017] [Indexed: 12/12/2022]
Abstract
TGF-β is a multifunctional cytokine affecting many cell types and implicated in tissue remodeling processes. Due to its many functions and cell-specific effects, the consequences of TGF-β signaling are process-and stage-dependent, and it is not uncommon that TGF-β exerts distinct and sometimes opposing effects on a disease progression depending on the stage and on the pathological changes associated with the stage. The mechanisms underlying cell- and process-specific effects of TGF-β are poorly understood. We are describing a novel pathway that mediates induction of angiogenesis in response to TGF-β1. We found that in endothelial cells (EC) TSP-4, a secreted extracellular matrix (ECM) protein is upregulated in response to TGF-β1 and mediates the effects of TGF-β1 on angiogenesis. Upregulation of TSP-4 does not require the synthesis of new protein, is not caused by decreased secretion of TSP-4, and is mediated by activation of SMAD3. Using Thbs4−/− mice and TSP-4 shRNA, we found that TSP-4 mediated pro-angiogenic functions on cultured EC and angiogenesis in vivo in response to TGF-β1. We observed ~ 3-fold increases in tumor mass and levels of angiogenesis markers in animals injected with TGF-β1, and these effects did not occur in Thbs4−/− animals. Injections of an inhibitor of TGF-β1 signaling SB431542 also decreased the weights of tumors and cancer angiogenesis. Our results from in vivo angiogenesis models and cultured EC document that TSP-4 mediates upregulation of angiogenesis by TGF-β1. Upregulation of pro-angiogenic TSP-4 and selective effects of TSP-4 on EC may contribute to stimulation of tumor growth by TGF-β despite the inhibition of cancer cell proliferation.
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Affiliation(s)
- S Muppala
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, OH, USA
| | - R Xiao
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, OH, USA
| | - I Krukovets
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, OH, USA
| | - D Verbovetsky
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, OH, USA
| | - R Yendamuri
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, OH, USA
| | - N Habib
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, OH, USA
| | - P Raman
- Department of Integrative Medical Sciences, North Ohio Medical University, Rootstown, OH, USA
| | - E Plow
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, OH, USA
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Mueller D, Roquemore AL, Jaworski M, Skinner CH, Miller J, Creely A, Raman P, Ruzic D. In situ measurement of low-Z material coating thickness on high Z substrate for tokamaks. Rev Sci Instrum 2014; 85:11E821. [PMID: 25430386 DOI: 10.1063/1.4893425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Rutherford backscattering of energetic particles can be used to determine the thickness of a coating of a low-Z material over a heavier substrate. Simulations indicate that 5 MeV alpha particles from an (241)Am source can be used to measure the thickness of a Li coating on Mo tiles between 0.5 and 15 μm thick. Using a 0.1 mCi source, a thickness measurement can be accomplished in 2 h of counting. This technique could be used to measure any thin, low-Z material coating (up to 1 mg/cm(2) thick) on a high-Z substrate, such as Be on W, B on Mo, or Li on Mo. By inserting a source and detector on a moveable probe, this technique could be used to provide an in situ measurement of the thickness of Li coating on NSTX-U Mo tiles. A test stand with an alpha source and an annular solid-state detector was used to investigate the measurable range of low-Z material thicknesses on Mo tiles.
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Affiliation(s)
- D Mueller
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A L Roquemore
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - M Jaworski
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - C H Skinner
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - J Miller
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A Creely
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - P Raman
- Department of Nuclear, Plasma, and Radiological Engineering, Center for Plasma Material Interaction, University of Illinois, Urbana, Illinois 61801, USA
| | - D Ruzic
- Department of Nuclear, Plasma, and Radiological Engineering, Center for Plasma Material Interaction, University of Illinois, Urbana, Illinois 61801, USA
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Leung Y, Teo S, Chua M, Raman P, Liu C, Chan A. SAT0106 Living Arrangements, Social Networks and Onset or Progression of Pain among Elderly in Singapore. Ann Rheum Dis 2014. [DOI: 10.1136/annrheumdis-2014-eular.2296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Otsuru S, Hofmann T, Raman P, Olson T, Horwitz E. Equivalent MSC preparations using two isolation methods. Cytotherapy 2014. [DOI: 10.1016/j.jcyt.2014.01.276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Fratter C, Raman P, Alston CL, Blakely EL, Craig K, Smith C, Evans J, Seller A, Czermin B, Hanna MG, Poulton J, Brierley C, Staunton TG, Turnpenny PD, Schaefer AM, Chinnery PF, Horvath R, Turnbull DM, Gorman GS, Taylor RW. RRM2B mutations are frequent in familial PEO with multiple mtDNA deletions. Neurology 2011; 76:2032-4. [PMID: 21646632 DOI: 10.1212/wnl.0b013e31821e558b] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- C Fratter
- Oxford Medical Genetics Laboratories, Churchill Hospital, Oxford, UK
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Babu MS, Raman P, Krishnan MG. Acute sarcoidosis--Heefordts-Waldenstrom syndrome. J Assoc Physicians India 2007; 55:156-7. [PMID: 17571752] [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: 05/15/2023]
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Ferdinandi ES, Raman P, Ross V. Synthesis of [14-14C] dexclamol hydrochloride and [14-14C] butaclamol hydrochloride. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580140514] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ferdinandi ES, Hicks DR, Verbestel W, Raman P. Synthesis of [14C]labelled pyrano[3,4-b]-and thiopyrano[3,4-b]indoles, and indeno[2,1-c]pyran derivatives. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580140315] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
Toxic epidermal necrolysis (TEN) is an acute life-threatening blistering disease characterized by involvement of the skin, multiple mucous membranes and internal organs. It is most commonly precipitated by the administration of medications like anticonvulsants. Neuroleptic malignant syndrome (NMS) is a rare complication of neuroleptic therapy characterized by catatonic behavior, generalized muscular rigidity, hyperthermia and autonomic dysfunction. An 18-year-old girl presenting with simultaneous appearance of TEN and NMS following anti-psychotic drugs given for bipolar mood disorder, is reported for the rare association and her complete recovery.
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Affiliation(s)
- K Muhammed
- Department of Dermatology and Venereology, Government Medical College, Kozhikode, Kerala, India.
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Abstract
The Membrane Protein Data Bank (MPDB) is an online, searchable, relational database of structural and functional information on integral, anchored and peripheral membrane proteins and peptides. Data originates from the Protein Data Bank and other databases, and from the literature. Structures are based on X-ray and electron diffraction, nuclear magnetic resonance and cryoelectron microscopy. The MPDB is searchable online by protein characteristic, structure determination method, crystallization technique, detergent, temperature, pH, author, etc. Record entries are hyperlinked to the PDB and Pfam for viewing sequence, three-dimensional structure and domain architecture, and for downloading coordinates. Links to PubMed are also provided. The MPDB is updated weekly in parallel with the Protein Data Bank. Statistical analysis of MPDB records can be performed and viewed online. A summary of the statistics as applied to entries in the MPDB is presented. The data suggest conditions appropriate for crystallization trials with novel membrane proteins.
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Affiliation(s)
- P. Raman
- Biophysics Program, The Ohio State University, Columbus, Ohio 43210 USA
| | - V. Cherezov
- College of Science and Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
- Chemistry Department, The Ohio State University, Columbus, Ohio, 43210 USA
| | - M. Caffrey
- College of Science and Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
- Biophysics Program, The Ohio State University, Columbus, Ohio 43210 USA
- Chemistry Department, The Ohio State University, Columbus, Ohio, 43210 USA
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Mavalankar D, Raman P, Dwivedi H, Jain ML. Managing equipment for emergency obstetric care in rural hospitals. Int J Gynaecol Obstet 2004; 87:88-97. [PMID: 15464790 DOI: 10.1016/j.ijgo.2004.07.003] [Citation(s) in RCA: 6] [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] [Received: 04/10/2003] [Revised: 04/08/2004] [Indexed: 10/26/2022]
Abstract
In resource-poor countries, substantial sums of money from governments and international donors are used to purchase equipment for health facilities. WHO estimates that 50-80% of such equipment remains non-functional. This article is based on experience from various projects in developing countries in Asia and Africa. The key issues in the purchase, distribution, installation, management and maintenance of equipment for emergency obstetric care (EmOC) services are identified and discussed. Some positive examples are described to show how common equipment management problems are solved.
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Affiliation(s)
- D Mavalankar
- Indian Institute of Management, Vastrapur, Ahmedabad 380015, India.
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Abstract
Previous studies from our laboratory as well as from others have suggested that the thiazolidinediones have the capacity to act as insulinomimetic agents, especially in the liver. In order to further characterize this insulinomimetic action, we evaluated the effect of troglitazone, a representative thiazolidinedione, on lactate- and glucagon-stimulated gluconeogenesis, in the presence or absence of insulin (10 nM) in isolated rat hepatocytes. The antigluconeogenic effect of troglitazone under basal (lactate-stimulated) conditions was found to be due to an elevation in the fructose 2,6-bisphosphate content, which was, however, not mediated by an activation of 6-phosphofructo 2-kinase. Troglitazone (125 and 250 microM) in the absence of insulin, produced a dose-dependent reduction in glucagon-stimulated gluconeogenesis, thereby suggesting an insulinomimetic effect. In addition, troglitazone (125 and 250 microM), in combination with insulin, produced an additive inhibition of gluconeogenesis during glucagon-stimulated conditions. However, unlike insulin, the metabolic mechanism responsible for these effects (in the presence or absence of insulin) does not involve fructose 2,6-bisphosphate.
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Affiliation(s)
- P Raman
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, AL 36849-5518, USA
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Raman P, Razavi H, Kelly JW. Titanium(IV)-mediated tandem deprotection-cyclodehydration of protected cysteine N-amides: biomimetic syntheses of thiazoline- and thiazole-containing heterocycles. Org Lett 2000; 2:3289-92. [PMID: 11029192 DOI: 10.1021/ol000178q] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [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: 11/30/2022]
Abstract
The scope and limitations of TiCl(4)-mediated Delta(2)-thiazoline synthesis via tandem deprotection-dehydrocyclization of trityl-protected cysteine N-amides is presented. While chemical yields are acceptable (53-96%), the stereochemical outcomes vary on the basis of structural considerations and reaction conditions (22-99% ee). Racemization at the C(2)-exomethine position limits the utility of this method for the formation of a thiazoline within a peptide. Treatment of a tritylated Cys-Cys dipeptide with TiCl(4) afforded the corresponding thiazole-thiazoline heterocycle 12 (38% yield, 97% ee).
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Affiliation(s)
- P Raman
- Department of Chemistry and The Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road (MB12), La Jolla, California 92037, USA
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Klabunde T, Petrassi HM, Oza VB, Raman P, Kelly JW, Sacchettini JC. Rational design of potent human transthyretin amyloid disease inhibitors. Nat Struct Biol 2000; 7:312-21. [PMID: 10742177 DOI: 10.1038/74082] [Citation(s) in RCA: 277] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The human amyloid disorders, familial amyloid polyneuropathy, familial amyloid cardiomyopathy and senile systemic amyloidosis, are caused by insoluble transthyretin (TTR) fibrils, which deposit in the peripheral nerves and heart tissue. Several nonsteroidal anti-inflammatory drugs and structurally similar compounds have been found to strongly inhibit the formation of TTR amyloid fibrils in vitro. These include flufenamic acid, diclofenac, flurbiprofen, and resveratrol. Crystal structures of the protein-drug complexes have been determined to allow detailed analyses of the protein-drug interactions that stabilize the native tetrameric conformation of TTR and inhibit the formation of amyloidogenic TTR. Using a structure-based drug design approach ortho-trifluormethylphenyl anthranilic acid and N-(meta-trifluoromethylphenyl) phenoxazine 4, 6-dicarboxylic acid have been discovered to be very potent and specific TTR fibril formation inhibitors. This research provides a rationale for a chemotherapeutic approach for the treatment of TTR-associated amyloid diseases.
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Affiliation(s)
- T Klabunde
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA
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Adams MD, Raman P, Judd RL. Comparative effects of englitazone and glyburide on gluconeogenesis and glycolysis in the isolated perfused rat liver. Biochem Pharmacol 1998; 55:1915-20. [PMID: 9714310 DOI: 10.1016/s0006-2952(98)00052-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [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: 11/16/2022]
Abstract
Englitazone (CP 68,722, Pfizer) is a member of a family of drugs known as thiazolidinediones. One member of this family, troglitazone (Rezulin), is currently utilized in the treatment of Type 2 diabetes. Previous studies have focused on the ability of englitazone to increase insulin sensitivity in various tissues. However, little information is available regarding the direct effect of englitazone on hepatic glucose metabolism in the absence of insulin. Therefore, the following studies were conducted to comparatively evaluate the effect of englitazone and glyburide (a representative sulfonylurea) on gluconeogenesis and glycolysis from various substrates in the isolated perfused rat liver (IPRL). In isolated perfused rat livers of 24-hr fasted rats infused with lactate (2 mM), englitazone (6.25 to 50 microM) produced a concentration-dependent decrease (32-93%) in hepatic gluconeogenesis. When dihydroxyacetone (1 mM) and fructose (1 mM) were used as metabolic substrates, englitazone inhibited gluconeogenesis by 31 and 15%, respectively, while increasing glycolysis by 42 and 50%. Similar effects on gluconeogenesis and glycolysis were observed with glyburide, even though the effects with glyburide were more acutely evident, reversible, and of a greater magnitude. Such data suggest alterations in hepatic glucose production may contribute to the decrease in plasma glucose concentrations observed in individuals treated with englitazone and glyburide. These alterations may include effects on several regulatory enzymes (e.g. fructose-1,6-bisphosphatase, pyruvate kinase, and phosphoenolpyruvate carboxykinase), which warrant further investigation.
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Affiliation(s)
- M D Adams
- Division of Molecular Pharmacology, College of Pharmacy and Health Sciences, Northeast Louisiana University, Monroe 71209-0470, USA
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Raman P, Foster SE, Stokes MC, Strenge JK, Judd RL. Effect of troglitazone (Rezulin) on fructose 2,6-bisphosphate concentration and glucose metabolism in isolated rat hepatocytes. Life Sci 1998; 62:PL89-94. [PMID: 9489515 DOI: 10.1016/s0024-3205(97)01177-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [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: 02/06/2023]
Abstract
The effect of troglitazone, an orally effective thiazolidinedione, on lactate- and glucagon-stimulated gluconeogenesis (in the absence of insulin) was examined in hepatocytes isolated from rats under different nutritional states. Hepatocytes obtained from fed or 20-24 hr fasted male Sprague-Dawley rats were incubated in Krebs-Henseleit Bicarbonate buffer (KHBC) (in presence or absence of 10.0 mM glucose) containing 2.0 mM [U-14C]lactate (0.1-0.25 microCi) with or without 10.0 nM glucagon and troglitazone (30.0 microM) or the appropriate vehicle. Aliquots were removed at specified endpoints and assayed for glucose and fructose 2,6-bisphosphate (F-2,6-P2) concentrations. In 20-24 hour starved hepatocytes, troglitazone produced a 26.1% inhibition of lactate-stimulated gluconeogenesis. This inhibitory effect of troglitazone on hepatic gluconeogenesis was further potentiated by incubation of the cells with glucose in vitro. In hepatocytes obtained from fasted rats (and incubated with 10 mM glucose in vitro) troglitazone reduced lactate-and glucagon-stimulated gluconeogenesis by 53% and 56%, respectively. This reduction in hepatic glucose production was associated with 1.06 and 1.04 fold increase in the hepatocyte F-2,6-P2 content. In isolated hepatocytes from fed animals and incubated with 10 mM glucose in vitro, troglitazone (15 and 30 microM) did not have any effect on either lactate- or glucagon-stimulated gluconeogenesis. However, 30 microM troglitazone significantly enhanced (36%) F-2,6-P2 concentrations during lactate-stimulated gluconeogenesis. These findings demonstrate that troglitazone decreases hepatic glucose production through alterations in the activity of one or more gluconeogenic/glycolytic enzymes, depending upon the nutritional state of the animal and the presence or absence of hormonal modulation. All of the effects of troglitazone in the present study were observed in the absence of insulin, suggesting an "insulinomimetic" effect. However, this does not exclude the possibility that troglitazone may also function as an "insulin sensitizer" in hepatic and certain other tissues.
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Affiliation(s)
- P Raman
- Division of Molecular Pharmacology, School of Pharmacy, Northeast Louisiana University, Monroe 71209, USA
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