Donor-recipient matching: Myths and realities

Journal of Hepatology

Volumn 58, Issue 4, 2013, Pages 811-820

  Briceño, Javier ^a   Ciria, Ruben ^a   De La Mata, Manuel ^a  

^a HOSPITAL UNIVERSITARIO REINA SOFÍA   (Spain)

Author keywords

Allocation; Donor recipient; Liver; Matching; Outcomes; Transplantation

Indexed keywords

ARTICLE; COST EFFECTIVENESS ANALYSIS; DONOR; DONOR RECIPIENT MATCHING; DONOR SELECTION; END STAGE LIVER DISEASE; FOLLOW UP; GRAFT RECIPIENT; GRAFT SURVIVAL; HEALTH CARE COST; HEALTH CARE POLICY; HOSPITAL ADMISSION; HUMAN; IMMUNOSUPPRESSIVE TREATMENT; LIVER CELL CARCINOMA; LIVER GRAFT; LIVER TRANSPLANTATION; MORTALITY; PRACTICE GUIDELINE; PRIORITY JOURNAL; RISK ASSESSMENT; SURGICAL TECHNIQUE; SURVIVAL;

EID: 84880964188     PISSN: 01688278     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.jhep.2012.10.020     Document Type: Note

References (106)

1. B. Alkofer, B. Samstein, J.V. Guarrera, C. Kin, D. Jan, and S. Bellemare Extended-criteria liver allografts Semin Liver Dis 26 2006 221 233
2. B. Müllhaupt, D. Dimitrioulis, J.T. Gerlach, and P.A. Clavien Hot topics in liver transplantation: organ allocation-extended criteria donor-living donor liver transplantation J Hepatol 48 2008 S58 S67
3. Anonymus Organ procurement and transplantation network-HRSA. Final rule with comment period Fed Reg 63 1998 16296 16338
4. R.S. Sung, P.L. Abt, D.M. Desai, C.A. Garvey, D.L. Segev, and D.B. Kaufman The right organ for the right recipient: the ninth annual American society of Transplant Surgeons' State-of-the-Art winter symposium Clin Transplant 25 2011 E592 E598
5. P.S. Kamath, R.H. Wiesner, M. Malinchoc, W. Kremers, T.M. Therneau, and C.L. Kosberg A model to predict survival in patients with end-stage liver disease Hepatology 33 2001 464 470 (Pubitemid 32119037)
6. R.M. Merion, D.E. Schaubel, D.M. Dykstra, R.B. Freeman, F.K. Port, and R.A. Wolfe The survival benefit of liver transplantation Am J Transplant 5 2005 307 313 (Pubitemid 40179517)
7. A. Rana, M.A. Hardy, K.J. Halazun, D.C. Woodland, L.E. Ratner, and B. Samstein Survival outcomes following liver transplantation (SOFT) score: a novel method to predict patient survival following liver transplantation Am J Transplant 8 2008 2537 2546
8. S. Gitto, S. Lorenzini, M. Biselli, F. Conti, P. Andreone, and Bernardi Allocation priority in non-urgent liver transplantation: an overview of proposed scoring systems Dig Liver Dis 41 2009 700 706
9. S.K. Asrani, and W.R. Kim Model for end-stage liver disease: end of the first decade Clin Liver Dis 15 2011 685 698
10. R.B. Freeman Jr. Model for end-stage liver disease (MELD) for liver allocation: a 5-year score card Hepatology 47 2008 1052 1057 (Pubitemid 351449696)
11. Merriam-Webster's on line dictionary: match. Available at: < http://mw1.merriam-webster.com/dictionary/match >. Accessed June 2012.
12. M. Malinchoc, P.S. Kamath, F.D. Gordon, C.J. Peine, J. Rank, and P.C. ter Borg A model to predict poor survival in patients undergoing transjugular intrahepatic portosystemic shunts Hepatology 31 2000 864 871 (Pubitemid 30169932)
13. P.S. Kamath, and W.R. Kim The model for end-stage liver disease (MELD) Hepatology 45 2007 797 805 (Pubitemid 46450631)
14. M. de la Mata, N. Cuende, J. Huet, A. Bernardos, A. Ferrón, and J. Santoyo Model for end-stage liver disease score-based allocation of donors for liver transplantation: a Spanish multicenter experience Transplantation 82 2006 1429 1435 (Pubitemid 44967624)
15. C. Francoz, J. Belghiti, D. Castaing, O. Chazouillêres, J.C. Duclos-Vallêe, and C. Duvoux Model for end-stage liver disease exceptions in the context of the French model for end-stage liver disease score-based liver allocation system Liver Transplant 17 2011 1137 1151
16. T.J. Weismüller, P. Fikatas, J. Schmidt, A.P. Barreiros, G. Otto, and S. Beckebaum Multicentric evaluation of model for end-stage liver disease-based allocation and survival after liver transplantation in Germany-limitations of the sickest first-concept Transplant Int 24 2011 91 99
17. M.R. Foxton, M.A.B. Al-Freah, A.J. Portal, E. Sizer, W. Bernal, and G. Auzinger Increased model for end-stage liver disease score at the time of liver transplant results in prolonged hospitalization and overall intensive care unit costs Liver Transplant 16 2010 668 677
18. R.S. Brown Jr., and J.R. Lake The survival impact of liver transplantation in the MELD era, and the future for organ allocation and distribution Am J Transplant 5 2005 203 204 (Pubitemid 40179505)
19. R.B. Freeman Jr., R.H. Wiesner, A. Harper, S.V. McDiarmid, J. Lake, and E. Edwards UNOS/OPTN Liver Disease Severity Score. UNOS/OPTN Liver and Intestine, and UNOS/OPTN Pediatric Transplantation Committees. The new liver allocation system: moving toward evidence-based transplantation policy Liver Transplant 8 2002 851 858
20. E. Cholongitas, L. Marelli, A. Kerry, M. Senzolo, D.W. Goodier, and D. Nair Different methods of creatinine measurement significantly affect MELD scores Liver Transplant 13 2007 523 529 (Pubitemid 46605854)
21. C. Francoz, D. Prie, W. Abdelrazek, R. Moreau, A. Mandot, and J. Belghiti Inaccuracies of creatinine and creatinine-based equations in candidates for liver transplantation with low creatinine: impact on the model for end-stage liver disease score Liver Transplant 16 2010 1169 1177
22. R.J. Porte, T. Lisman, A. Tripodi, S.H. Caldwell, and J.F. Trotter The coagulation in liver disease study group. The international normalized ratio (INR) in the MELD score: problems and solutions Am J Transplant 10 2010 1349 1353
23. C.K. Argo, G.J. Stukenborg, T.M. Schmitt, S.C. Kumer, C.L. Berg, and P.G. Northup Regional variability in symptom-based MELD exceptions: a response to organ shortage? Am J Transplant 11 2011 2353 2361
24. K. Washburn Model for end stage liver disease and hepatocellular carcinoma: a moving target Transplant Rev 24 2010 11 17
25. K. Roayaie, and S. Feng Allocation policy for hepatocellular carcinoma in the MELD area: room for improvement? Liver Transplant 13 2007 S36 S43
26. P. Sharma, D.E. Schaubel, Q. Gong, M. Guidinger, and R.M. Merion End-stage liver disease candidates at the highest model for end-stage liver disease scores have higher wait-list mortality than status-1A candidates Hepatology 55 2012 192 198
27. A. Cárdenas, and P. Ginés Predicting mortality in cirrhosis-serum sodium helps N Eng J Med 359 2008 1060 1062
28. R.M. Merion, R.A. Wolfe, D.M. Dykstra, A.B. Leichtman, B. Gillespie, and P.J. Held Longitudinal assessment of mortality risk among candidates for liver transplantation Liver Transplant 9 2003 12 18 (Pubitemid 36104909)
29. D.M. Heuman, A.A. Mihas, A. Habib, H.S. Gilles, R.T. Stravitz, and A.J. Sanyal MELD-XI: a rational approach to "Sickest First" liver transplantation in cirrhotic patients requiring anticoagulant therapy Liver Transplant 13 2007 30 37 (Pubitemid 46099971)
30. S.C. Huo, T.I. Huo, H.C. Lin, C.W. Chi, P.C. Lee, and F.W. Tseng Is the corrected creatinine model for end-stage liver disease a feasible strategy to adjust gender difference in organ allocation for liver transplantation? Transplantation 84 2007 1406 1412 (Pubitemid 350294715)
31. K. Barber, S. Madden, J. Allen, D. Collett, J. Neuberger, and A. Gimson Elective liver transplant list mortality: development of a United Kingdom end-stage liver disease Transplantation 92 2011 469 476
32. P. Sharma, D.E. Schaubel, C.S. Sima, R.M. Merion, and A.S. Lok Re-weighting the model for end-stage liver disease score components Gastroenterology 135 2008 1575 1581
33. S. Habib, B. Berk, C.C. Chang, A.J. Demetris, P. Fontes, and I. Dvorchik MELD and predictionof post-liver transplantation survival Liver Transplant 12 2006 440 447
34. H.Y. Yoo, and P.J. Thuluvath Short-term post-liver transplant survival after the introduction of MELD scores for organ allocation in the United States Liver Int 25 2005 536 541 (Pubitemid 40861902)
35. N. Onaca, M.F. Levy, G.J. Netto, M.J. Thomas, E.Q. Sanchez, and S. Chinnakotla Pretransplant MELD score as a predictor of outcome after liver transplantation for chronic hepatitis C Am J Transplant 3 2003 626 630 (Pubitemid 36612847)
36. N.M. Desai, K.C. Mange, M.D. Crawford, P.L. Abt, A.M. Frank, and J.W. Markmann Predicting outcome after liver transplantation: utility of the model for end-stage liver disease and a newly derived discrimination function Transplantation 77 2004 99 106 (Pubitemid 38116879)
37. R.M. Merion Current status and future of liver transplantation Semin Liver Dis 30 2010 411 421
38. D.E. Schaubel, C.S. Sima, N.P. Goodrich, S. Feng, and R.M. Merion The survival benefit of deceased donor liver transplantation as a function of candidate disease severity and donor quality Am J Transplant 8 2008 419 425 (Pubitemid 351175358)
39. D.E. Schaubel, M.K. Guidinger, and S.W. Biggins Survival benefit-based deceased-donor liver allocation Am J Transplant 9 2009 970 981
40. R.M. Merion, P. Sharma, A.K. Mathur, and D.E. Schaubel Evidence-based development of liver allocation: a review Transplant Int 24 2011 965 972
41. S. Feng, N.P. Goodrich, J.L. Bragg-Gresham, D.M. Dykstra, J.D. Punch, and M.A. DebRoy Characteristics associated with liver graft failure: the concept of a donor risk index Am J Transplant 6 2006 783 790 (Pubitemid 43345017)
42. M.L. Volk, A.S. Lok, S.J. Pelletier, P.A. Ubel, and R.A. Hayward Impact of the model for end-stage liver disease allocation policy on the use of high-risk organs for liver transplantation Gatroenterology 2008 1568 1574
43. G. Persad, A. Wertheimer, and E.J. Emanuel Principles for allocation of scarce medical interventions Lancet 373 2009 423 431
44. A.J. Billitier Who goes first? J Public Health Manag Pract 11 2005 267 268
45. D. Parfit Equity and priority Ratio 10 1997 202 221
46. N.-H. Hsieh, A. Strudler, and D. Waserman The numbers problem Philos Publ Aff 34 2006 352 372 (Pubitemid 44430666)
47. L.B. Russell, J.E. Siegel, N. Daniels, M.R. Gold, B.R. Luce, and J.S. Mandelblatt Cost-effectiveness analysis as a guide to resource allocation in health: roles and limitations M.R. Gold, J.E. Siegel, L.B. Russell, M.C. Weinstein, Cost-effectiveness in health and medicine 1996 Oxford University Press New York 3 24
48. E.W. Steyerberg, M.J.C. Eijkemans, F.E. Harrell, and J.D.F. Habbema Prognostic modelling with logistic regression analysis: a comparison of selection and estimation methods in small data sets Stat Med 19 2000 1059 1079 (Pubitemid 30238915)
49. J.G. Evans The rationing debate: rationing health care by age: the case against BMJ 314 1997 822
50. R. Foster, M. Zimmerman, and J.F. Trotter Expanding donor options: marginal, living, and split donors Clin Liver Dis 11 2007 417 429 (Pubitemid 46990956)
51. N.R. Barshes, I.B. Horwitz, L. Franzini, J.M. Vierling, and J.A. Goss Waitlist mortality decreases with increased use of extended criteria donor liver grafts at adult liver transplant centers Am J Transplant 7 2007 1265 1270 (Pubitemid 46643109)
52. A.J. Tector, R.S. Mangus, P. Chestovich, R. Vianna, J.A. Fridell, and M.L. Milgrom Use of extended criteria livers decreases wait time for liver transplantation without ad-versely impacting posttransplant survival Ann Surg 244 2006 439 450
53. S.K. Akkina, S.K. Asrani, Y. Peng, P. Stock, W.R. Kim, and A.K. Israni Development of organ-specific donor risk indices Liver Transplant 18 2012 395 404
54. R.W. Busuttil, and K. Tanaka The utility of marginal donors in liver transplantation Liver Transplant 9 2003 651 663 (Pubitemid 36874450)
55. F. Durand, Renz, B. Alkofer, P. Burra, P.-A. Clavien, and R.J. Porte Report of the Paris consensus meeting on expanded criteria donors in liver transplantation Liver Transplant 14 2008 1694 1707
56. W.J. Wall, R. Mimeault, D.R. Grant, and M. Bloch The use of older donor livers for hepatic transplantation Transplantation 49 1990 377 381 (Pubitemid 20088180)
57. C.D. Anderson, N. Vachharajani, M. Doyle, J.A. Lowell, J.R. Wellen, and S. Shenoy Advanced age alone does nor affect patient or graft survival after liver transplantation J Am Coll Surg 207 2008 847 852
58. R. Verzaro, M. Minervini, and B. Gridelli Toward "no age limit" for liver transplant donors Transplantation 85 2008 1869 1870
59. J. Briceño, and R. Ciria Early graft dysfunction after liver transplantation Transplant Proc 42 2010 631 633
60. H. Yersiz, A. Shaked, K. Olthoff, D. Imagawa, C. Shackleton, and P. Martin Correlation between donor age and the pattern of liver graft recovery after transplantation Transplantation 60 1995 790 794
61. P.P. Reese, S.B. Sonawane, A. Thomasson, H. Yeh, and J.F. Markmann Donor age and cold ischemia interact to produce inferior 90-day liver allograft survival Transplantation 85 2008 1737 1744
62. J.R. Cassuto, S.A. Patel, G. Tsoulfas, M.S. Orloff, and P.L. Abt The cumulative effects of cold ischemic time and older donor age on liver graft survival J Surg Res 148 2008 38 44
63. J. Briceño, R. Ciria, M. de la Mata, S. Rufián, and P. López-Cillero Prediction of graft dysfunction based on extended criteria donors in the model for end-stage liver disease score era Transplantation 90 2010 530 539
64. J. Briceño, G. Solórzano, and C. Pera A proposal for scoring marginal liver grafts Transplant Int 13 2000 S249 S252
65. M.S. Roberts, D.C. Angus, C.L. Bryce, Z. Valenta, and L. Weissfeld Survival after liver transplantation in the United States: a disease-specific analysis of the UNOS database Liver Transplant 10 2004 886 897 (Pubitemid 38979259)
66. D.E. Moore, I.D. Feurer, T. Speroff, D.L. Gorden, J.K. Wright, and R.S. Chari Impact of donor, tecnical, and recipient risk factors on survival and quality of life after liver transplantation Arch Surg 140 2005 273 277 (Pubitemid 41001820)
67. A.W. Avolio, A.S. Chirico, S. Agnes, G. Sganga, R. Gaspari, and F. Frongillo Prediction of 6-month survival after liver transplantation using Cox regression Transplant Proc 36 2004 529 532 (Pubitemid 38534311)
68. D.G. Maluf, E.B. Edwards, and H.M. Kauffman Utilization of extended donor criteria liver allograft: is the elevated risk of failure independent of the model for end-stage liver dis-ease score of the recipient? Transplantation 82 2006 1653 1657 (Pubitemid 46035646)
69. G.K. Bonney, M.A. Aldersley, S. Asthana, G.J. Toogood, S.G. Pollard, and J.P. Lodge Donor risk index and MELD interactions in predicting long-term graft survival: a single-centre experience Transplantation 87 2009 1858 1863
70. M. Angelico, U. Cillo, S. Fagiuoli, A. Gasbarrini, C. Gavrila, and T. Marianelli On behalf of the liver match investigators. Liver match, a prospective observational cohort study on liver transplantation in Italy: study design and current practice of donor-recipient matching Dig Liver Dis 43 2011 155 164
71. J.J. Blok, A.E. Braat, R. Adam, A.K. Burroughs, H. Putter, and N.G. Kooreman For the European Intestine Transplant Association and The Eurotransplant Liver Intestine Advisory Committee. Validation of the donor risk index in orthotopic liver transplantation within the Eurotransplant region Liver Transplant 18 2012 113 120
72. S. Feng The dilemma of high-risk deceased donor livers: who should get them? Liver Transplant 16 2010 S60 S64
73. W. Arns, F. Citterio, and J.M. Campistol Old-for-old - new strategies for renal transplantation Nephrol Dial Transplant 22 2007 336 341 (Pubitemid 46189873)
74. X. Rogiers, and E. Sieders Split-liver transplantation: an underused resource in liver transplantation Transplantation 86 2008 493 499
75. P.R. Salvalaggio, N. Dzebisashvili, K.E. MacLeod, K.L. Lentine, A. Gheorgian, and M.A. Schnitzler The interaction among donor characteristics, severity of liver disease, and the cost of liver transplantation Liver Transplant 17 2011 233 242
76. B. Koneru, and G. Dikdan Hepatic steatosis and liver transplantation current clinical and experimental perspectives Transplantation 73 2002 325 330 (Pubitemid 34174277)
77. C.J. Imber, S.D. St Peter, A. Handa, and P.J. Friend Hepatic steatosis and its relationship to transplantation Liver Transplant 8 2002 415 423 (Pubitemid 34520769)
78. J. Briceño, J. Padillo, S. Rufián, G. Solórzano, and C. Pera Assignment of steatotic livers by the Mayo model for end-stage liver disease Transplant Int 18 2005 577 583 (Pubitemid 41726861)
79. A.L. Spitzer, O.B. Lao, A.A.S. Dick, R. Bakthavatsalam, J.B. Halldorson, and M.M. Yeh The biopsied donor liver: incorporating macrosteatosis into high-risk donor assessment Liver Transplant 16 2010 874 884
80. J.F. Renz A critical analysis of liver allograft utilization from the US deceased donor pool Liver Transplant 16 2010 543 547
81. M.G. Amin, M.P. Wolf, J.A. TenBrook Jr., R.B. Freeman Jr., S.J. Cheng, and D.S. Pratt Expanded criteria donor grafts for deceased donor liver transplantation under the MELD system: a decision analysis Liver Transplant 10 2004 1468 1475 (Pubitemid 40028378)
82. R.M. Merion Doc, should I accept this offer or not? Liver Transplant 10 2004 1476 1477 (Pubitemid 40028379)
83. G.N. Ioannou Development and validation of a model predicting graft survival after liver transplantation Liver Transplant 12 2006 1594 1606 (Pubitemid 44742538)
84. J.B. Halldorson, R. Bakthavatsalam, O. Fix, and J.D. Reyes Perkins. D-MELD, a simple predictor of post liver transplant mortality for optimization of donor/recipient matching Am J Transplant 9 2009 318 326
85. J. Neuberger, and O. James Guidelines for selection of patients for liver transplantation in the era of donor-organ shortage Lancet 354 1999 1636 1639 (Pubitemid 29515965)
86. V. Mazzaferro, J.M. Llovet, R. Miceli, S. Bhoori, M. Schiavo, and L. Mariani Predicting survival after liver transplantation in patients with hepatocellular carcinoma beyond the Milan criteria: a retrospective, exploratory analysis Lancet Oncol 10 2009 35 43
87. J. Neuberger, A. Gimson, M. Davies, M. Akyol, J. O'Grady, and A. Burroughs Selection of patients for liver transplantation and allocation of donated livers in UK Gut 57 2008 252 257 (Pubitemid 351158055)
88. J. Bruix, and J.M. Llovet Prognostic prediction and treatment strategy in hepatocellular carcinoma Hepatology 35 2002 519 524 (Pubitemid 34183954)
89. A.W. Avolio, U. Cillo, M. Salizzoni, L. De Carlis, M. Colledan, and G.E. Gerunda On behalf of the donor-to-recipient Italian liver transplant (D2R-ILTx) study group. Balancing donor and recipient risk factors in liver transplantation: the value of D-MELD with particular reference to HCV recipients Am J Transplant 11 2011 2724 2736
90. P. Dutkowski, C.E. Oberkofler, K. Slankamenac, M.A. Puhan, E. Schadde, and B. Müllhaupt Are there better guidelines for allocation in liver transplantation? a novel score targeting justice and utility in the model for end-stage liver disease era Ann Surg 254 2011 745 753
91. F. Piscaglia, V. Camaggi, M. Ravaioli, G.L. Grazi, M. Zanello, and S. Leoni A new priority policy for patients with hepatocellular carcinoma awaiting liver transplantation within the model for end-stage liver disease system Liver Transplant 13 2007 857 866 (Pubitemid 46947850)
92. M.E. Facciuto, M.K. Singh, U. Katta, S. Samaniego, J. Sharma, and M. Rodriguez-Davalos Liver transplantation for hepatocellular carcinoma: defining the impact of using extended criteria liver allografts Transplantation 92 2011 446 452
93. G.N. Ioannou, J.D. Perkins, and R.L. Carithers Jr. Liver Transplantation for hepatocellular carcinoma: impact of the MELD allocation system and predictors of survival Gastroenterology 134 2008 1342 1351 (Pubitemid 351615357)
94. M.L. Volk, S. Vijan, and J.A. Marrero A novel model measuring the harm of transplanting hepatocellular carcinoma exceeding Milan criteria Am J Transplant 8 2008 839 846 (Pubitemid 351347750)
95. C. Toso, S. Asthana, D.L. Bigam, A.M. Shapiro, and N.M. Kneteman Reassessing selection criteria prior to liver transplantation for hepatocellular carcinoma utilizing the scientific registry of transplant recipients database Hepatology 49 2009 832 838
96. G. Ballardini, E. De Raffele, P. Groff, P. Bioulac-Sage, A. Grassi, and S. Ghetti Timing of reinfection and mechanisms of hepatocellular damage in transplanted hepatitis c virus-reinfected liver Liver Transplant 8 2002 10 20 (Pubitemid 34092667)
97. E.J. Gane The natural history of recurrent hepatitis c and what influences this Liver Transplant 14 2008 S36 S44
98. M. Berenguer, M. Prieto, J.M. Rayon, J. Mora, M. Pastor, and V. Ortiz Natural history of clinically compensated hepatitis c virus-related graft cirrhosis after liver transplantation Hepatology 32 2000 852 858
99. L. Llado, J. Castellote, and J. Figueras Is retransplantation an option for recurrent hepatitis c cirrhosis after liver transplantation? J Hepatol 42 2005 468 472 (Pubitemid 40347307)
100. M. Berenguer, M. Prieto, F. San Juan, J.M. Rayon, F. Martinez, and D. Carrasco Contribution of donor age to the recent decrease in patient survival among hcv-infected liver transplant recipients Hepatology 36 2002 202 210 (Pubitemid 34700779)
101. M. Berenguer, V. Aguilera, M. Prieto, C. Ortiz, M. Rodriguez, and F. Gentili Worse recent efficacy of antiviral therapy in liver transplant recipients with recurrent hepatitis C: impact of donor age and baseline cirrhosis Liver Transplant 15 2009 738 746
102. J. Briceno, R. Ciria, M. Pleguezuelo, M. de la Mata, J. Muntane, and A. Naranjo Impact of donor graft steatosis on overall outcome and viral recurrence after liver transplantation for hepatitis C virus cirrhosis Liver Transplant 15 2009 37 48
103. K.D. Watt, E.R. Lyden, J.M. Gulizia, and T.M. McCashland Recurrent hepatitis C posttransplant: early preservation injury may predict poor outcome Liver Transplant 12 2006 134 139
104. M. Knight, K. Barber, A. Gimson, D. Collett, and J. Neuberger Implications of changing the minimal survival benefit in liver transplantation Liver Transplant 18 2012 549 557
105. Briceño J, Cruz M, Prieto M, Navasa M, Ortiz J, Orti R, et al. Donor-recipient matching in liver transplantation based on a rule-system built on a multiobjective artificial neural network. ESOT Congress 2011.
106. R. Varian Hal Intermediate microeconomics: a modern approach 7th ed. 2006 W. W. Norton & Company 0-393-92702-4 p. 490