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Fitzgerald TW, Gerety SS, Jones WD, van Kogelenberg M, King DA, McRae J, Morley KI, Parthiban V, Al-Turki S, Ambridge K, Barrett DM, Bayzetinova T, Clayton S, Coomber EL, Gribble S, Jones P, Krishnappa N, Mason LE, Middleton A, Miller R, Prigmore E, Rajan D, Sifrim A, Tivey AR, Ahmed M, Akawi N, Andrews R, Anjum U, Archer H, Armstrong R, Balasubramanian M, Banerjee R, Baralle D, Batstone P, Baty D, Bennett C, Berg J, Bernhard B, Bevan AP, Blair E, Blyth M, Bohanna D, Bourdon L, Bourn D, Brady A, Bragin E, Brewer C, Brueton L, Brunstrom K, Bumpstead SJ, Bunyan DJ, Burn J, Burton J, Canham N, Castle B, Chandler K, Clasper S, Clayton-Smith J, Cole T, Collins A, Collinson MN, Connell F, Cooper N, Cox H, Cresswell L, Cross G, Crow Y, D’Alessandro M, Dabir T, Davidson R, Davies S, Dean J, Deshpande C, Devlin G, Dixit A, Dominiczak A, Donnelly C, Donnelly D, Douglas A, Duncan A, Eason J, Edkins S, Ellard S, Ellis P, Elmslie F, Evans K, Everest S, Fendick T, Fisher R, Flinter F, Foulds N, Fryer A, Fu B, Gardiner C, Gaunt L, Ghali N, Gibbons R, Gomes Pereira SL, Goodship J, Goudie D, et alFitzgerald TW, Gerety SS, Jones WD, van Kogelenberg M, King DA, McRae J, Morley KI, Parthiban V, Al-Turki S, Ambridge K, Barrett DM, Bayzetinova T, Clayton S, Coomber EL, Gribble S, Jones P, Krishnappa N, Mason LE, Middleton A, Miller R, Prigmore E, Rajan D, Sifrim A, Tivey AR, Ahmed M, Akawi N, Andrews R, Anjum U, Archer H, Armstrong R, Balasubramanian M, Banerjee R, Baralle D, Batstone P, Baty D, Bennett C, Berg J, Bernhard B, Bevan AP, Blair E, Blyth M, Bohanna D, Bourdon L, Bourn D, Brady A, Bragin E, Brewer C, Brueton L, Brunstrom K, Bumpstead SJ, Bunyan DJ, Burn J, Burton J, Canham N, Castle B, Chandler K, Clasper S, Clayton-Smith J, Cole T, Collins A, Collinson MN, Connell F, Cooper N, Cox H, Cresswell L, Cross G, Crow Y, D’Alessandro M, Dabir T, Davidson R, Davies S, Dean J, Deshpande C, Devlin G, Dixit A, Dominiczak A, Donnelly C, Donnelly D, Douglas A, Duncan A, Eason J, Edkins S, Ellard S, Ellis P, Elmslie F, Evans K, Everest S, Fendick T, Fisher R, Flinter F, Foulds N, Fryer A, Fu B, Gardiner C, Gaunt L, Ghali N, Gibbons R, Gomes Pereira SL, Goodship J, Goudie D, Gray E, Greene P, Greenhalgh L, Harrison L, Hawkins R, Hellens S, Henderson A, Hobson E, Holden S, Holder S, Hollingsworth G, Homfray T, Humphreys M, Hurst J, Ingram S, Irving M, Jarvis J, Jenkins L, Johnson D, Jones D, Jones E, Josifova D, Joss S, Kaemba B, Kazembe S, Kerr B, Kini U, Kinning E, Kirby G, Kirk C, Kivuva E, Kraus A, Kumar D, Lachlan K, Lam W, Lampe A, Langman C, Lees M, Lim D, Lowther G, Lynch SA, Magee A, Maher E, Mansour S, Marks K, Martin K, Maye U, McCann E, McConnell V, McEntagart M, McGowan R, McKay K, McKee S, McMullan DJ, McNerlan S, Mehta S, Metcalfe K, Miles E, Mohammed S, Montgomery T, Moore D, Morgan S, Morris A, Morton J, Mugalaasi H, Murday V, Nevitt L, Newbury-Ecob R, Norman A, O'Shea R, Ogilvie C, Park S, Parker MJ, Patel C, Paterson J, Payne S, Phipps J, Pilz DT, Porteous D, Pratt N, Prescott K, Price S, Pridham A, Procter A, Purnell H, Ragge N, Rankin J, Raymond L, Rice D, Robert L, Roberts E, Roberts G, Roberts J, Roberts P, Ross A, Rosser E, Saggar A, Samant S, Sandford R, Sarkar A, Schweiger S, Scott C, Scott R, Selby A, Seller A, Sequeira C, Shannon N, Sharif S, Shaw-Smith C, Shearing E, Shears D, Simonic I, Simpkin D, Singzon R, Skitt Z, Smith A, Smith B, Smith K, Smithson S, Sneddon L, Splitt M, Squires M, Stewart F, Stewart H, Suri M, Sutton V, Swaminathan GJ, Sweeney E, Tatton-Brown K, Taylor C, Taylor R, Tein M, Temple IK, Thomson J, Tolmie J, Torokwa A, Treacy B, Turner C, Turnpenny P, Tysoe C, Vandersteen A, Vasudevan P, Vogt J, Wakeling E, Walker D, Waters J, Weber A, Wellesley D, Whiteford M, Widaa S, Wilcox S, Williams D, Williams N, Woods G, Wragg C, Wright M, Yang F, Yau M, Carter NP, Parker M, Firth HV, FitzPatrick DR, Wright CF, Barrett JC, Hurles ME. Large-scale discovery of novel genetic causes of developmental disorders. Nature 2015; 519:223-8. [PMID: 25533962 PMCID: PMC5955210 DOI: 10.1038/nature14135] [Show More Authors] [Citation(s) in RCA: 834] [Impact Index Per Article: 83.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 12/04/2014] [Indexed: 12/23/2022]
Abstract
Despite three decades of successful, predominantly phenotype-driven discovery of the genetic causes of monogenic disorders, up to half of children with severe developmental disorders of probable genetic origin remain without a genetic diagnosis. Particularly challenging are those disorders rare enough to have eluded recognition as a discrete clinical entity, those with highly variable clinical manifestations, and those that are difficult to distinguish from other, very similar, disorders. Here we demonstrate the power of using an unbiased genotype-driven approach to identify subsets of patients with similar disorders. By studying 1,133 children with severe, undiagnosed developmental disorders, and their parents, using a combination of exome sequencing and array-based detection of chromosomal rearrangements, we discovered 12 novel genes associated with developmental disorders. These newly implicated genes increase by 10% (from 28% to 31%) the proportion of children that could be diagnosed. Clustering of missense mutations in six of these newly implicated genes suggests that normal development is being perturbed by an activating or dominant-negative mechanism. Our findings demonstrate the value of adopting a comprehensive strategy, both genome-wide and nationwide, to elucidate the underlying causes of rare genetic disorders.
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research-article |
10 |
834 |
2
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Monnier A, Schüth F, Huo Q, Kumar D, Margolese D, Maxwell RS, Stucky GD, Krishnamurty M, Petroff P, Firouzi A, Janicke M, Chmelka BF. Cooperative Formation of Inorganic-Organic Interfaces in the Synthesis of Silicate Mesostructures. Science 1993; 261:1299-303. [PMID: 17731857 DOI: 10.1126/science.261.5126.1299] [Citation(s) in RCA: 718] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A model is presented to explain the formation and morphologies of surfactant-silicate mesostructures. Three processes are identified: multidentate binding of silicate oligomers to the cationic surfactant, preferential silicate polymerization in the interface region, and charge density matching between the surfactant and the silicate. The model explains present experimental data, including the transformation between lamellar and hexagonal mesophases, and provides a guide for predicting conditions that favor the formation of lamellar, hexagonal, or cubic mesostructures. Model Q(230) proposed by Mariani and his co-workers satisfactorily fits the x-ray data collected on the cubic mesostructure material. This model suggests that the silicate polymer forms a unique infinite silicate sheet sitting on the gyroid minimal surface and separating the surfactant molecules into two disconnected volumes.
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32 |
718 |
3
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Firouzi A, Kumar D, Bull LM, Besier T, Sieger P, Huo Q, Walker SA, Zasadzinski JA, Glinka C, Nicol J. Cooperative organization of inorganic-surfactant and biomimetic assemblies. Science 1995; 267:1138-43. [PMID: 7855591 DOI: 10.1126/science.7855591] [Citation(s) in RCA: 664] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A model that makes use of the cooperative organization of inorganic and organic molecular species into three dimensionally structured arrays is generalized for the synthesis of nanocomposite materials. In this model, the properties and structure of a system are determined by dynamic interplay among ion-pair inorganic and organic species, so that different phases can be readily obtained through small variations of controllable synthesis parameters, including mixture composition and temperature. Nucleation, growth, and phase transitions may be directed by the charge density, coordination, and steric requirements of the inorganic and organic species at the interface and not necessarily by a preformed structure. A specific example is presented in which organic molecules in the presence of multiply charged silicate oligomers self-assemble into silicatropic liquid crystals. The organization of these silicate-surfactant mesophases is investigated with and without interfacial silicate condensation to separate the effects of self-assembly from the kinetics of silicate polymerization.
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30 |
664 |
4
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Spiller R, Aziz Q, Creed F, Emmanuel A, Houghton L, Hungin P, Jones R, Kumar D, Rubin G, Trudgill N, Whorwell P, Clinical Services Committee of The British Society of Gastroenterology. Guidelines on the irritable bowel syndrome: mechanisms and practical management. Gut 2007; 56:1770-98. [PMID: 17488783 PMCID: PMC2095723 DOI: 10.1136/gut.2007.119446] [Citation(s) in RCA: 538] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 04/20/2007] [Accepted: 05/01/2007] [Indexed: 12/14/2022]
Abstract
BACKGROUND IBS affects 5-11% of the population of most countries. Prevalence peaks in the third and fourth decades, with a female predominance. AIM To provide a guide for the assessment and management of adult patients with irritable bowel syndrome. METHODS Members of the Clinical Services Committee of The British Society of Gastroenterology were allocated particular areas to produce review documents. Literature searching included systematic searches using electronic databases such as Pubmed, EMBASE, MEDLINE, Web of Science, and Cochrane databases and extensive personal reference databases. RESULTS Patients can usefully be classified by predominant bowel habit. Few investigations are needed except when diarrhoea is a prominent feature. Alarm features may warrant further investigation. Adverse psychological features and somatisation are often present. Ascertaining the patients' concerns and explaining symptoms in simple terms improves outcome. IBS is a heterogeneous condition with a range of treatments, each of which benefits a small proportion of patients. Treatment of associated anxiety and depression often improves bowel and other symptoms. Randomised placebo controlled trials show benefit as follows: cognitive behavioural therapy and psychodynamic interpersonal therapy improve coping; hypnotherapy benefits global symptoms in otherwise refractory patients; antispasmodics and tricyclic antidepressants improve pain; ispaghula improves pain and bowel habit; 5-HT(3) antagonists improve global symptoms, diarrhoea, and pain but may rarely cause unexplained colitis; 5-HT(4) agonists improve global symptoms, constipation, and bloating; selective serotonin reuptake inhibitors improve global symptoms. CONCLUSIONS Better ways of identifying which patients will respond to specific treatments are urgently needed.
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Practice Guideline |
18 |
538 |
5
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Nugent SG, Kumar D, Rampton DS, Evans DF. Intestinal luminal pH in inflammatory bowel disease: possible determinants and implications for therapy with aminosalicylates and other drugs. Gut 2001; 48:571-7. [PMID: 11247905 PMCID: PMC1728243 DOI: 10.1136/gut.48.4.571] [Citation(s) in RCA: 482] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Measurements of luminal pH in the normal gastrointestinal tract have shown a progressive increase in pH from the duodenum to the terminal ileum, a decrease in the caecum, and then a slow rise along the colon to the rectum. Some data in patients with ulcerative colitis suggest a substantial reduction below normal values in the right colon, while limited results in Crohn's disease have been contradictory. Determinants of luminal pH in the colon include mucosal bicarbonate and lactate production, bacterial fermentation of carbohydrates and mucosal absorption of short chain fatty acids, and possibly intestinal transit. Alterations in these factors, as a result of mucosal disease and changes in diet, are likely to explain abnormal pH measurements in inflammatory bowel disease (IBD). It is conceivable that reduced intracolonic pH in active ulcerative colitis impairs bioavailability of 5-aminosalicylic acid from pH dependent release formulations (Asacol, Salofalk) and those requiring cleavage by bacterial azo reductase (sulphasalazine, olsalazine, balsalazide), but further pharmacokinetic studies are needed to confirm this possibility. Reports that balsalazide and olsalazine may be more efficacious in active and quiescent ulcerative colitis, respectively, than Asacol suggest that low pH may be a more critical factor in patients taking directly pH dependent release than azo bonded preparations. Reduced intracolonic pH also needs to be considered in the development of pH dependent colonic release formulations of budesonide and azathioprine for use in ulcerative and Crohn's colitis. This paper reviews methods for measuring gut pH, its changes in IBD, and how these may influence current and future therapies.
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review-article |
24 |
482 |
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Klessig DF, Durner J, Noad R, Navarre DA, Wendehenne D, Kumar D, Zhou JM, Shah J, Zhang S, Kachroo P, Trifa Y, Pontier D, Lam E, Silva H. Nitric oxide and salicylic acid signaling in plant defense. Proc Natl Acad Sci U S A 2000; 97:8849-55. [PMID: 10922045 PMCID: PMC34022 DOI: 10.1073/pnas.97.16.8849] [Citation(s) in RCA: 386] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Salicylic acid (SA) plays a critical signaling role in the activation of plant defense responses after pathogen attack. We have identified several potential components of the SA signaling pathway, including (i) the H(2)O(2)-scavenging enzymes catalase and ascorbate peroxidase, (ii) a high affinity SA-binding protein (SABP2), (iii) a SA-inducible protein kinase (SIPK), (iv) NPR1, an ankyrin repeat-containing protein that exhibits limited homology to IkappaBalpha and is required for SA signaling, and (v) members of the TGA/OBF family of bZIP transcription factors. These bZIP factors physically interact with NPR1 and bind the SA-responsive element in promoters of several defense genes, such as the pathogenesis-related 1 gene (PR-1). Recent studies have demonstrated that nitric oxide (NO) is another signal that activates defense responses after pathogen attack. NO has been shown to play a critical role in the activation of innate immune and inflammatory responses in animals. Increases in NO synthase (NOS)-like activity occurred in resistant but not susceptible tobacco after infection with tobacco mosaic virus. Here we demonstrate that this increase in activity participates in PR-1 gene induction. Two signaling molecules, cGMP and cyclic ADP ribose (cADPR), which function downstream of NO in animals, also appear to mediate plant defense gene activation (e.g., PR-1). Additionally, NO may activate PR-1 expression via an NO-dependent, cADPR-independent pathway. Several targets of NO in animals, including guanylate cyclase, aconitase, and mitogen-activated protein kinases (e.g., SIPK), are also modulated by NO in plants. Thus, at least portions of NO signaling pathways appear to be shared between plants and animals.
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Review |
25 |
386 |
7
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Singal PK, Li T, Kumar D, Danelisen I, Iliskovic N. Adriamycin-induced heart failure: mechanism and modulation. Mol Cell Biochem 2000; 207:77-86. [PMID: 10888230 DOI: 10.1023/a:1007094214460] [Citation(s) in RCA: 299] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Adriamycin (doxorubicin) is one of the most effective chemotherapeutic agents against a variety of cancers, but its usefulness is seriously curtailed by the risk of developing heart failure. Available laboratory evidence suggests that an increase in oxidative stress, brought about by increased free radical production and decreased myocardial endogenous antioxidants, plays an important role in the pathogenesis of heart failure. Adriamycin-induced apoptosis and hyperlipidemia may also be involved in the process. Probucol, a lipid-lowering drug and an antioxidant, completely prevents the occurrence of heart failure by reducing oxidative stress as well as by the modulation of apoptosis and high lipid concentrations. Thus, combined therapy with adriamycin and probucol has a high potential for optimizing the treatment of cancer patients.
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Review |
25 |
299 |
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Cha Y, Erez T, Reynolds IJ, Kumar D, Ross J, Koytiger G, Kusko R, Zeskind B, Risso S, Kagan E, Papapetropoulos S, Grossman I, Laifenfeld D. Drug repurposing from the perspective of pharmaceutical companies. Br J Pharmacol 2017; 175:168-180. [PMID: 28369768 DOI: 10.1111/bph.13798] [Citation(s) in RCA: 247] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/06/2017] [Accepted: 03/08/2017] [Indexed: 02/01/2023] Open
Abstract
Drug repurposing holds the potential to bring medications with known safety profiles to new patient populations. Numerous examples exist for the identification of new indications for existing molecules, most stemming from serendipitous findings or focused recent efforts specifically limited to the mode of action of a specific drug. In recent years, the need for new approaches to drug research and development, combined with the advent of big data repositories and associated analytical methods, has generated interest in developing systematic approaches to drug repurposing. A variety of innovative computational methods to enable systematic repurposing screens, experimental as well as through in silico approaches, have emerged. An efficient drug repurposing pipeline requires the combination of access to molecular data, appropriate analytical expertise to enable robust insights, expertise and experimental set-up for validation and clinical development know-how. In this review, we describe some of the main approaches to systematic repurposing and discuss the various players in this field and the need for strategic collaborations to increase the likelihood of success in bringing existing molecules to new indications, as well as the current advantages, considerations and challenges in repurposing as a drug development strategy pursued by pharmaceutical companies. LINKED ARTICLES This article is part of a themed section on Inventing New Therapies Without Reinventing the Wheel: The Power of Drug Repurposing. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.2/issuetoc.
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Review |
8 |
247 |
9
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Kumar D, Chernenko S, Moussa G, Cobos I, Manuel O, Preiksaitis J, Venkataraman S, Humar A. Cell-mediated immunity to predict cytomegalovirus disease in high-risk solid organ transplant recipients. Am J Transplant 2009; 9:1214-22. [PMID: 19422346 DOI: 10.1111/j.1600-6143.2009.02618.x] [Citation(s) in RCA: 227] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Late-onset cytomegalovirus (CMV) disease commonly occurs after discontinuation of antiviral prophylaxis. We determined the utility of testing CD8+ T-cell response against CMV as a predictor of late-onset CMV disease after a standard course of antiviral prophylaxis. Transplant patients at high-risk for CMV disease were enrolled. CD8+ T-cell-mediated immunity (CMI) was tested using the QuantiFERON-CMV assay at baseline, 1, 2 and 3 months posttransplant by measurement of interferon-gamma response to whole blood stimulation with a 21-peptide pool. The primary outcome was the ability of CMI testing to predict CMV disease in the first 6 months posttransplant. There were 108 evaluable patients (D+/R+ n = 39; D-/R+ n = 34; D+/R- n = 35) of whom 18 (16.7%) developed symptomatic CMV disease. At the end of prophylaxis, CMI was detectable in 38/108 (35.2%) patients (cutoff 0.1 IU/mL interferon-gamma). CMV disease occurred in 2/38 (5.3%) patients with a detectable interferon-gamma response versus 16/70 (22.9%) patients with a negative response; p = 0.038. In the subgroup of D+/R- patients, CMV disease occurred in 1/10 (10.0%) patients with a detectable interferon-gamma response (cutoff 0.1 IU/mL) versus 10/25 (40.0%) patients with a negative CMI, p = 0.12. Monitoring of CMI may be useful for predicting late-onset CMV disease.
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227 |
10
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Abstract
Current knowledge about adriamycin cardiomyopathy indicates that the major cause of this condition is increased oxidative stress although the drug's antitumor action in patients may involve other mechanisms. Controversies about the different antioxidants in preventing cardiomyopathy likely stem from the fact that antioxidants must be effective in both the lipid and water phases, and the dose must be optimal, in order to be protective. Probucol, an antioxidant and promoter of endogenous antioxidants, is one such agent. Conducting clinical trials with an optimal dose of probucol is the next step and should make this great anticancer drug safer and more efficient in the fight against the cancer.
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Review |
28 |
208 |
11
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Salloway S, Ferris S, Kluger A, Goldman R, Griesing T, Kumar D, Richardson S. Efficacy of donepezil in mild cognitive impairment: a randomized placebo-controlled trial. Neurology 2005; 63:651-7. [PMID: 15326237 DOI: 10.1212/01.wnl.0000134664.80320.92] [Citation(s) in RCA: 206] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To evaluate the efficacy and safety of the acetylcholinesterase inhibitor donepezil in a placebo-controlled trial in patients with mild cognitive impairment (MCI). METHODS A total of 270 patients with MCI were enrolled in a 24-week, multicenter, randomized, double-blind, placebo-controlled study. Patients were randomized to receive donepezil (n = 133; 5 mg/day for 42 days, followed by forced dose escalation to 10 mg/day) or placebo (n = 137). Primary efficacy measures were the New York University (NYU) Paragraph Delayed Recall test and the Alzheimer disease (AD) Cooperative Study Clinician's Global Impression of Change for MCI (ADCS CGIC-MCI). Secondary efficacy measures included the modified AD Assessment Scale-cognitive subscale (ADAS-cog), the Patient Global Assessment (PGA), and additional neuropsychologic measures. Efficacy analyses were performed on intent-to-treat (ITT) and fully evaluable (FE) populations. RESULTS Primary efficacy measures of the NYU Paragraph Recall test and the ADCS CGIC-MCI did not show significant treatment effects in the ITT population. Some secondary measures showed effects favoring donepezil. More donepezil-treated patients showed improvements in ADAS-cog total scores, in tests of attention and psychomotor speed, and in PGA scores. More donepezil-treated than placebo-treated patients experienced adverse events, most of which were mild to moderate and transient. CONCLUSION Although significant treatment effects were not seen in the primary efficacy measures, outcomes on secondary measures suggest promising directions for further evaluation of donepezil treatment in patients with MCI.
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Research Support, Non-U.S. Gov't |
20 |
206 |
12
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Kumar D, Schumacher K, du Fresne von Hohenesche C, Grün M, Unger K. MCM-41, MCM-48 and related mesoporous adsorbents: their synthesis and characterisation. Colloids Surf A Physicochem Eng Asp 2001. [DOI: 10.1016/s0927-7757(01)00638-0] [Citation(s) in RCA: 204] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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24 |
204 |
13
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Abstract
Although researchers in radiation and cancer biology have known about the existence of free radicals and their potential role in pathobiology for several decades, cardiac biologists only began to take notice of these noxious species in the 1970s. Exponential growth of free radical research occurred after the discovery of superoxide dismutase in 1969. This antioxidant enzyme is responsible for the dismutation of superoxide radical--a free radical chain initiator. A fine balance between free radicals and a variety of endogenous antioxidants is believed to exist. Any disturbance in this equilibrium in favour of free radicals causes an increase in oxidative stress and initiates subcellular changes leading to cardiomyopathy and heart failure. Our knowledge about the role of free radicals in the pathogenesis of cardiac dysfunction is fast approaching the point where newer therapies employing antioxidants are in sight.
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Editorial |
27 |
203 |
14
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Hannan EL, van Ryn M, Burke J, Stone D, Kumar D, Arani D, Pierce W, Rafii S, Sanborn TA, Sharma S, Slater J, DeBuono BA. Access to coronary artery bypass surgery by race/ethnicity and gender among patients who are appropriate for surgery. Med Care 1999; 37:68-77. [PMID: 10413394 DOI: 10.1097/00005650-199901000-00010] [Citation(s) in RCA: 197] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The study sought to determine if there were race/ethnicity or gender differences in access to coronary artery bypass graft (CABG) surgery among patients who have been designated as appropriate and as necessary for that surgery according to the RAND methodology. METHODS RAND appropriateness and necessity criteria were used to identify a race/gender stratified sample of postangiography patients who would benefit from coronary artery bypass graft surgery. These patients were tracked for 3 months to determine if they had undergone coronary artery bypass graft surgery in New York State. Subjects were a total of 1,261 postangiography patients in eight New York hospitals in 1994 to 1996. Measures included percentages of patients for whom coronary artery bypass graft surgery was appropriate and necessary undergoing surgery by race/ethnicity and gender, as well as multivariate odds ratios for race/ethnicity and gender. RESULTS After controlling for age, payer, number of vessels diseased, and presence of left main disease, African-American and Hispanic patients were found to be significantly less likely to undergo coronary artery bypass graft surgery than white non-Hispanic patients (respective odds ratios 0.64 and 0.60). When "necessity" was used as a criterion instead of "appropriateness," significant differences in access for African-American patients remained. The gatekeeper physician recommended surgery only 10% of the time that patients did not undergo "appropriate" coronary artery bypass graft surgery, and this percentage did not vary significantly by race/ethnicity or gender of the patient. CONCLUSIONS Even after controlling for appropriateness and necessity for coronary artery bypass graft surgery in a prospective study, African-American patients had significant access problems in obtaining coronary artery bypass graft surgery. These problems appeared not to be related to patient refusals.
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26 |
197 |
15
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Sultan AH, Monga AK, Kumar D, Stanton SL. Primary repair of obstetric anal sphincter rupture using the overlap technique. BRITISH JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1999; 106:318-23. [PMID: 10426237 DOI: 10.1111/j.1471-0528.1999.tb08268.x] [Citation(s) in RCA: 178] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To evaluate the feasibility of a new technique of primary overlap anal sphincter repair instead of end-to-end repair. SETTING A teaching hospital and a district general hospital. METHODS Between June 1995 and November 1996, two obstetricians repaired 32 anal sphincters ruptured during vaginal delivery. A ruptured internal sphincter was repaired separately and the torn ends of the external sphincter were overlapped and sutured with 3/0 polydioxanone sulphate sutures (Ethicon, Edinburgh, UK). MAIN OUTCOME MEASURES Bowel function, clinical assessment, anal endosonography and manometry performed at a mean of 140 days after delivery. RESULTS Eight percent of the women experienced incontinence of flatus. Fifteen percent had persistent sonographic external sphincter defects, and 44% had internal sphincter defects. The maximum mean resting pressure was 58 mmHg (range 37-135) and the mean maximum incremental squeeze pressure 54 mmHg (range 8-104). None had defaecatory difficulty and no complications were encountered with the new technique of repair. CONCLUSIONS Reservations regarding the feasibility of the overlap technique of primary repair are unfounded, as both subjective and objective outcomes are favourable compared with other studies using end-to-end approximation. A multicentre randomised study of the overlap vs end-to-end repair technique is now planned.
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Clinical Trial |
26 |
178 |
16
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Huprikar S, Danziger-Isakov L, Ahn J, Naugler S, Blumberg E, Avery RK, Koval C, Lease ED, Pillai A, Doucette KE, Levitsky J, Morris MI, Lu K, McDermott JK, Mone T, Orlowski JP, Dadhania DM, Abbott K, Horslen S, Laskin BL, Mougdil A, Venkat VL, Korenblat K, Kumar V, Grossi P, Bloom RD, Brown K, Kotton CN, Kumar D. Solid organ transplantation from hepatitis B virus-positive donors: consensus guidelines for recipient management. Am J Transplant 2015; 15:1162-72. [PMID: 25707744 DOI: 10.1111/ajt.13187] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 12/08/2014] [Accepted: 12/24/2014] [Indexed: 01/25/2023]
Abstract
Use of organs from donors testing positive for hepatitis B virus (HBV) may safely expand the donor pool. The American Society of Transplantation convened a multidisciplinary expert panel that reviewed the existing literature and developed consensus recommendations for recipient management following the use of organs from HBV positive donors. Transmission risk is highest with liver donors and significantly lower with non-liver (kidney and thoracic) donors. Antiviral prophylaxis significantly reduces the rate of transmission to liver recipients from isolated HBV core antibody positive (anti-HBc+) donors. Organs from anti-HBc+ donors should be considered for all adult transplant candidates after an individualized assessment of the risks and benefits and appropriate patient consent. Indefinite antiviral prophylaxis is recommended in liver recipients with no immunity or vaccine immunity but not in liver recipients with natural immunity. Antiviral prophylaxis may be considered for up to 1 year in susceptible non-liver recipients but is not recommended in immune non-liver recipients. Although no longer the treatment of choice in patients with chronic HBV, lamivudine remains the most cost-effective choice for prophylaxis in this setting. Hepatitis B immunoglobulin is not recommended.
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Practice Guideline |
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Danziger-Isakov L, Kumar D. Vaccination in solid organ transplantation. Am J Transplant 2013; 13 Suppl 4:311-7. [PMID: 23465023 DOI: 10.1111/ajt.12122] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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163 |
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Unger KK, Kumar D, Grün M, Büchel G, Lüdtke S, Adam T, Schumacher K, Renker S. Synthesis of spherical porous silicas in the micron and submicron size range: challenges and opportunities for miniaturized high-resolution chromatographic and electrokinetic separations. J Chromatogr A 2000; 892:47-55. [PMID: 11045479 DOI: 10.1016/s0021-9673(00)00177-1] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Classical silica technology has reached its limit with respect to an ultimate minimum particle size of about 2 microm in diameter. Here, a novel process is presented which allows one to synthesize porous silica beads and control their particle diameter in situ, within the range of 0.2-2.0 microm. As a result, no sizing is required and losses of silica are avoided. Furthermore, the process enables one to control in situ the pore structural parameters and the surface chemistry of the silica beads. Even though surface funtionalized silicas made according to this process can principally be applied in fast HPLC the column pressure drop will be high even for short columns. In addition, the column efficiency, expressed in terms of the theoretical plate height is about H-2d(p) in the best case and limited by the A and C term of the Van Deemter equation. In other words the gain in total plate number when using 1-2 microm silica beads in short columns is minimal as compared to longer columns packed with 5 microm particles. Capillary electrochromatography (CEC) as a hybrid method enables the application of micron size as well as submicron size particles. This consequently enhances column efficiency by a factor of 5-10 when compared to HPLC. The use of short CEC columns packed with submicron size silicas provides the basis for fast and efficient miniaturized systems. The most significant feature of CEC as compared to HPLC is that the former allows one to resolve polar and ionic analytes in a single run. An alternative method for miniaturization is capillary electrophoresis (CE) which generates extremely high efficiencies combined with fast analysis. Its application, however, is limited to ionic substances.
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Review |
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Bhatta RS, Chandasana H, Chhonker YS, Rathi C, Kumar D, Mitra K, Shukla PK. Mucoadhesive nanoparticles for prolonged ocular delivery of natamycin: In vitro and pharmacokinetics studies. Int J Pharm 2012; 432:105-12. [PMID: 22569234 DOI: 10.1016/j.ijpharm.2012.04.060] [Citation(s) in RCA: 159] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 04/13/2012] [Accepted: 04/23/2012] [Indexed: 12/16/2022]
Abstract
The aim of this study was to prepare natamycin encapsulated lecithin/chitosan mucoadhesive nanoparticles (NPs) for prolonged ocular application. These NPs were characterized by their mean particle size 213nm, encapsulation efficiency 73.57%, with a theoretical drug loading 5.09% and zeta potential +43. In vitro release exhibited a biphasic drug release profile with initial burst followed by a very slow drug release. The MIC(90) and zone of inhibition of NPs showed similar antifungal activity as compared to marketed suspension and free natamycin against Candida albicans and Aspergillus fumigates. The ocular pharmacokinetics of NPs and marketed formulation were evaluated in NZ rabbits. The NPs exhibit significant mucin adhesion. The AUC((0-∞)) was increased up to 1.47 fold and clearance was decreased up to 7.4-fold as compared to marketed suspension. The PK-PD and pharmacokinetic simulation was carried out to estimate optimum dosing regimen for good efficacy. Thus, lecithin/chitosan NPs could be considered useful approach aiming to prolong ocular residence and reduce dosing frequency.
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Research Support, Non-U.S. Gov't |
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Abstract
Upper small bowel motility was recorded for more than 30 h in each of 22 patients with the irritable bowel syndrome (IBS) and in two control groups, one consisting of 10 healthy volunteers and the other of 5 patients with inflammatory bowel disease. When subjects underwent a long period of intermittent mental stress, one or more of three motor abnormalities occurred in 19 patients; and only one abnormality was seen in 1 control (p less than 0.0001). These abnormalities were the total abolition of migrating motor complexes under stress, and abnormal irregular contractile activity, which was either spontaneous or evoked by stress. Sometimes the irregular contractile activity coincided with the occurrence of typical IBS symptoms. Males predominated (p = 0.05) among those with spontaneous irregular motor activity, who tended to have more symptoms (p = 0.014) than did those affected only by stress. The data suggest that irritable bowel syndrome is a paroxysmal motor disorder which may be detected in the small bowel and which may be either spontaneous or evoked.
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Abstract
This study examined changes in the risk-adjusted mortality associated with coronary artery bypass grafting procedures performed in New York State during the first 4 years of New York's Cardiac Surgery Reporting System (1989 to 1992). To track performance over time, surgeons and hospitals were subdivided into three groups on the basis of their performance in 1989. The risk-adjusted mortality for each of the three groups was computed for 1992 and compared with their 1989 mortality. The results indicate that all groups of providers exhibited large reductions in the risk-adjusted mortalities, with the groups that showed the highest initial mortalities manifesting the most improvement. However, the group rankings remained the same in 1992 as they were in 1989. For example, when the hospital groups were based on the terciles of risk-adjusted mortality observed in 1989, the risk-adjusted mortality decreased from 2.72% to 2.19% for group 1, from 4.24% to 2.51% for group 2, and from 7.12% to 2.77% for group 3. Notably, the risk-adjusted mortalities of the three groups were all significantly different from one another in 1989, but were not significantly different from one another in 1992. Another interesting finding was that the volume of operations performed by the various provider groups did not change substantially in the 4-year period.
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Alexiewicz JM, Kumar D, Smogorzewski M, Klin M, Massry SG. Polymorphonuclear leukocytes in non-insulin-dependent diabetes mellitus: abnormalities in metabolism and function. Ann Intern Med 1995; 123:919-24. [PMID: 7486486 DOI: 10.7326/0003-4819-123-12-199512150-00004] [Citation(s) in RCA: 140] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVE To determine basal levels of cytosolic calcium ([Ca2+]i) and phagocytic activity in polymorphonuclear leukocytes (PMNLs) from patients with non-insulin-dependent diabetes (NIDDM). DESIGN Prospective cohort study. SETTING A university-county hospital. MEASUREMENTS Cytosolic calcium levels, adenosine triphosphate (ATP) content, and phagocytosis of PMNLs from patients with NIDDM and from controls. INTERVENTION In patients with NIDDM, we evaluated the effect of treatment with an oral hypoglycemic agent (glyburide) on [Ca2+]i levels, ATP content, and the phagocytosis of PMNLs. PATIENTS 22 controls and 34 patients with NIDDM were examined. Fifteen patients were studied before and after 3 months of treatment with glyburide. RESULTS Polymorphonuclear leukocytes from patients with NIDDM showed significantly elevated basal levels of [Ca2+]i (68 +/- 9.6 compared with 43 +/- 4.9 nmol/L; P < 0.01); reduced ATP content (1.30 +/- 0.58 compared with 2.35 +/- 0.45 nmol/10(6) PMNLs; P < 0.01); and impaired phagocytosis (117 +/- 21.0 compared with 145 +/- 17.4 micrograms oil/10(7) PMNLs per minute; P < 0.01) compared with controls. There was a direct and significant correlation (P < 0.01, r = 0.80) between [Ca2+]i levels in PMNLs and serum glucose levels and an inverse correlation between phagocytic ability and [Ca2+]i levels (P < 0.01; r = 0.62) as well as between phagocytic activity and fasting serum glucose levels (P < 0.01, r = 0.54) in patients with NIDDM. Glyburide therapy resulted in significant reduction in fasting serum glucose levels; in PMNLs, this treatment resulted in a significant reduction in [Ca2+]i levels, a significant increase in ATP content, and a significant improvement of phagocytosis. CONCLUSIONS Patients with NIDDM have elevated [Ca2+]i levels in PMNLs. This abnormality is probably induced by hyperglycemia and is primarily responsible for the imparied phagocytosis seen in these patients.
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Deen KI, Kumar D, Williams JG, Olliff J, Keighley MR. Anal sphincter defects. Correlation between endoanal ultrasound and surgery. Ann Surg 1993; 218:201-5. [PMID: 8343001 PMCID: PMC1242931 DOI: 10.1097/00000658-199308000-00013] [Citation(s) in RCA: 139] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE This study was performed to (1) correlate and sphincter defects, identified by endoanal ultrasound with operative findings, and (2) define the appearance of such sphincter defects as seen at operation. SUMMARY BACKGROUND DATA Endoanal ultrasonography is a minimally invasive method of imaging the anal sphincter complex and enables identification of anal sphincter defects. Little is known about the accuracy and limitations of endoanal ultrasound in identifying such defects. Furthermore, there are no data about the appearances of these endosonic sphincter defects as seen at operation. METHODS Forty-four patients (40 women; age range, 26 to 80 years; mean age, 56 years) with fecal incontinence, undergoing pelvic floor repair, were investigated by endoanal ultrasound before operation. Endosonic findings were correlated with the appearances of external anal sphincter, internal anal sphincter, and intersphincteric space, at operation. Diagnosis of the site and type of defect was made by macroscopic appearances. Uncertainty about the type of sphincter defect was resolved by obtaining muscle biopsies for histology. RESULTS All external sphincter defects seen by endoanal ultrasound (n = 23) were confirmed at operation. Twenty-one of 22 internal sphincter defects identified by endosonography also were confirmed at operation. In ten patients with a neuropathic anal sphincter complex, the morphology was normal on endosonography, and this was confirmed at operation. (Sensitivity and specificity of 100% for external anal sphincter; 100% and 95.5%, respectively, for internal and sphincter) CONCLUSIONS These data show that endoanal ultrasound is an accurate method of identifying anal sphincter defects.
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Danzinger-Isakov L, Kumar D. Guidelines for vaccination of solid organ transplant candidates and recipients. Am J Transplant 2009; 9 Suppl 4:S258-62. [PMID: 20070687 DOI: 10.1111/j.1600-6143.2009.02917.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Kumar D, Blumberg EA, Danziger-Isakov L, Kotton CN, Halasa NB, Ison MG, Avery RK, Green M, Allen UD, Edwards KM, Miller G, Michaels MG. Influenza vaccination in the organ transplant recipient: review and summary recommendations. Am J Transplant 2011; 11:2020-30. [PMID: 21957936 DOI: 10.1111/j.1600-6143.2011.03753.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Influenza virus causes a spectrum of illness in transplant recipients with a high rate of lower respiratory disease. Seasonal influenza vaccination is an important public health measure recommended for transplant recipients and their close contacts. Vaccine has been shown to be safe and generally well tolerated in both adult and pediatric transplant recipients. However, responses to vaccine are variable and are dependent on various factors including time from transplantation and specific immunosuppressive medication. Seasonal influenza vaccine has demonstrated safety and no conclusive evidence exists for a link between vaccination and allograft dysfunction. Annually updated trivalent inactivated influenza vaccines have been available and routinely used for several decades, although newer influenza vaccination formulations including high-dose vaccine, adjuvanted vaccine, quadrivalent inactivated vaccine and vaccine by intradermal delivery system are now available or will be available in the near future. Safety and immunogenicity data of these new formulations in transplant recipients requires investigation. In this document, we review the current state of knowledge on influenza vaccines in transplant recipients and make recommendations on the use of vaccine in both adult and pediatric organ transplant recipients.
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Review |
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