Valdes Laboratories - Basic Research Laboratory

Qazzaz HMAM, Cao ZT, Bolanowski DD, Clark BJ, Valdes RJr. De Novo Biosynthesis and Radiolabeling of Mammalian Digitalis-Like Factors. Clin Chem 2004; (50)3:612-620.

Qazzaz HMH, Lane AN, Valdes RJr. Structural identification of digoxin-like immuno- reactive factors (DLIFs) using NMR spectroscopy. Clin Chem 2003;49 (suppl):A130 (Abstract E-45)

El-Masri MA, Clark BJ, Qazzaz HM, Valdes R Jr. Human Adrenal Cells in Culture Produce Both Ouabain-like and Dihydroouabain-like Factors. Clin Chem 2002;48-10:1720-1730.

Qazzaz HAM, Clemmens JM, Clark BJ, Valdes JrR. Production of 14C-labeled mammalian ouabain-like factors (OLF) using mouse adrenal Y-1 cells. J Clin Ligand Assay 2002

Qazzaz HMAM, Clements JM, Clark BJ, Valdes RJr. Mevastatin, a cholesterol-lowering drug, inhibits the production of mammalian cardenolides (MC) by mouse adrenalcortical (Y-!) Cells. Abstract P1-510, Endocrine Society's 84th Annual Meeting, San Francisco (June 19-22, 2002).

Qazzaz HMH, Clements JM, El-Masri AM, Valdes RJr. Relative potencies of the Mammalian cardenolides (MC) and their plant counterparts (PC). Clin Chem 2002;48(6): A132 Supp.

Qazzaz HMA, Valdes R Jr. Structural Polymorphis tissue distribution of the endogenous mammalian cardenolides. Clin Chem 2001;47(6):A207

Linder MW, Antonini-Green D, Nota F, Johnson NA, Adams JE, Lacefield N, Valdes R Jr. Predictive value of CYP2C9 genotyping for identification of subjects requiring low Warfarin maintenance dosages. Clin Chem 2001;47:A75.

Qazzaz HMA, Bolanowski D, Falkner K, Valdes R Jr. Cytochrome P450 mediates metabolism of Digoxin and its congeners in mammalian liver microsomes. ClinChem 2001;47(6):A17 Supp.

Qazzaz HMA, Bolanowski D, Valdes R Jr. Synthesis of four structurally-related mammalian cardinolides by adrenal Y1 cells: molar ratios and relative concentrations. Clin Chem 2001;47(6):A17 Supp.

Qazzaz HMA, El-Masri MA, Valdes RJr. Secretion of a Lactone-Hydrogenated Ouabain-Like Effector of Sodium Potassium-Adenosine Triphosphatase Activity by Adrenal Cells. Endocrinology 2000;14:3200-3209.

Grider G, El-Mallakh RS, Huff MO, Buss TJR, Miller J, Valdes RJr. Endogenous digoxin-like immunoreactive factor (DLIF) serum concentrations are decreased in manic bi-polar patients compared to normal controls. Journal of Affective Disorders 1999;54:261-267.

Jortani SA, Valdes RJr. Digoxin and its related endogenous factors. Crit Rev Clin Lab Sci. 1997;34:225-274.

Jortani SA, Helm RA, Valdes RJr. Inhibition of Na,K-Atpase by oleandrin and oleandrigenin and their detection by digoxin immunoassays. Clin Chem 1996:42;1654-1658.

Qazzaz MAM, Jortani SA, Poole JM, Valdes, RJr. Evidence for presence of a reduced form of digoxin-like immunoreactive factor (dihydro-DLIF) in mammalian tissues. Clin Chem 1996;42:1092-1099.

Qazzaz MAM, Goudy SL, Valdes RJr. Deglycosylated products of endogenous digoxin-like immunoreactive factor (DLIF) in mammalian tissue. J Biol Chem 1996;271:8731-8737.

Qazzaz MAM, Valdes RJr. Simultaneous isolation of endogenous digoxin-like immunoreactive factor, ouabain-like factor, and deglycosylated congeners from mammalian tissue. Arch Biochem Biophys 1996;328:193-200.

Jortani SA, Miller JJ, Valdes RJr. Resolving clinically discrepant digoxin results: a case study involving multiple interferences. J Clin Ligand Assay 1996;19:131-137.

Miller JJ, Straub RW, Valdes RJr. Analytical performance of a monoclonal digoxin assay with increased specificity on the ACS:180. Therap Drug Monitor 1996;18:65-72.

Qazzaz HMAM, Goudy S, Miller JJ, Valdes RJr. Treatment of human serum with sulfosalicylic acid structurally alters digoxin and endogenous digoxin-like immunoreactive factor. Therapeutic Drug Monitoring 1995;17:53-59.

Miller JJ, Straub RW, Valdes, RJr. A digoxin immunoassay in which cross- reactivity of digoxin metabolites is proportional to their biological activity. Clin Chem 1994;40:1898-1903.

Valdes RJr. Improving the specificity of digoxin immunoassays. Wiener Klinische Wochenschrift (supplement) 1992;191:55 59.

Craig HR, Knight A, Valdes RJr. Binding of endogenous digoxin-like immunoreactive factor to serum proteins during normal and hypertensive pregnancy. J Clin Immunoassay 1991;14:245 250.

Shaikh IM, Lau BWC, Siegfried BA, Valdes RJr. Isolation of digoxin-like immunoreactive factors from mammalian adrenal cortex. J Biol Chem 1991;266:13672 13678.

Matheke ML, Valdes RJr. Antibody specificity reduces interference by endogenous digoxin-like immunoreactive factors. J Clin Immunoassay 1989;12:115 121.

Matheke ML, Valdes RJr. A physician's office-based digoxin assay (Seralyzer) evaluated for interference by endogenous digoxin-like factors. Ann Clin Lab Sci 1989;19:168 174.

Lau BWC, Valdes RJr. Criteria for identifying endogenous compounds in plasma as digoxin-like immunoreactive factors in humans. Clin Chim Acta 1988;175:67 78.

Lackner TE, Lau BWC, Parvin C, Valdes RJr. Endogenous digoxin-like immunoreactivity in elderly patients with normal serum creatinine concentrations. Clin Pharm 1988;7:449 53.

Siegfried BS, Valdes RJr. Excretion of endogenous digoxin-like immunoreactive factors in human urine is a function of urine flow rate. Clin Chem 1988;34:960 64.

Valdes RJr, Hagberg JM, Vaughan TE, Lau BWC, Seals DR, Ehsani AA. Endogenous digoxin-like immunoreactivity in blood is increased during prolonged strenuous exercise. Life Sciences 1988;42:103 110.

Skogen WF, Rea MR, Valdes RJr. Improved interassay correlation of digoxin results in patients with and without renal failure by elimination of digoxin-like immunoreactive factors. Clin Chem 1987;33:837 839.

Skogen WF, Rea MR, Valdes RJr. Endogenous digoxin-like immunoreactive factors eliminated from serum by hydrophobic silica gel extraction and enzyme immunoassay. Clin Chem. 1987;33:401 404.

Valdes RJr. Measuring digoxin in serum by immunoassay: Potential problems due to endogenous digoxin-like immunoreactive factors. American Association for Clinical Chemistry, Washington, D.C., Therapeutic Drug Monitoring and Emergency Toxicology. 1986;7:1 8.

Delfert D, Valdes RJr. Impact of digoxin-like immunoreactive factors on digoxin measurements by immunoassays. J Clin Immunoassay. 1985;8:157 164.

Valdes RJr. Endogenous digoxin immunoactive factor in human subjects. Federation Proc. 1985;44:2800 2805.

Valdes RJr. Endogenous digoxin-like immunoactive factors: false positive digoxin measurements in clinical groups and potential physiologic implication. Clin Chem. 1985;31:1525 1532.

Valdes RJr, Graves SW. Protein binding of endogenous digoxin immunoactive factors in human serum and its variation with clinical condition. J Clin Endocrinol Metab. 1985;60:1135 1143.

Valdes RJr, Graves SW, Knight AB, Craig HR. Endogenous Digoxin-immunoactivity is elevated in hypertensive pregnancy. In: Lal H,La Bella F, Lane J, eds. Endocoids, New York: Alan R. Liss, Inc. Prog Clin Biol Res. 1985;192:229 232.

Valdes RJr. Endogenous digoxin immunoactive substance measured in several patient populations. In Lal, H., La Bella, F., Lane, J., eds., Endocoids, New York, Alan R. Liss, Inc., Prog Clin Biol Res. 1985;192:221 228.

Valdes RJr, Brown B, Graves S. Variable cross reactivity of digoxin metabolites in digoxin immunoassays. Am J Clin Path. 1984;82:210 213.

Graves SW, Valdes RJr, Brown BA, Knight AB, Craig HR. Endogenous digoxin immunoreactive substance in human pregnancies. J Clin Endocrinol Metab. 1984;58:748 751. (Valdes as senior author)

Graves SW, Brown B, Valdes RJr. Endogenous digoxin-like substance in patients with renal impairment. Ann Int Med. 1983;99:604 608.

Valdes RJr, Graves SW, Brown BA, Landt M. Endogenous substance in newborn infants causing false positive digoxin measurements. J Pediatrics 1983;102:947 950.

Craver J, Valdes RJr. Anomalous serum digoxin concentrations in uremia. Ann Int Med. 1983;98:483 484.

Krogstad DJ, Granich GG, Murray PR, Pfaller MA, Valdes RJr. Heparin Interference with the radioemzymatic and EMIT Assays for aminoglycosides. Clin Chem. 1982;28:1517 1521.

Valdes RJr, Savory G, Bruns D, Renoe B, Savory J, Wills, MR. Performance assessment of the GAMMFLOTM automated radioimmunoassay system by assaying for digoxin. Clin Chem. 1979;25:1254 1258.

Gupta A, Joshi P, Jortani SA, Valdes RJr., Thorkelsson T, Verjee Z, Shemie S. A case of nondigitalis cardiac glycoside toxicity. Therap Drug Monitor 1997;19:711-714.

Jortani SA, Pinar A, Johnson NA, Valdes RJr. Validity of unbound digoxin measurements by immunoassays in presence of antidote (Digibind®). Clinica Chimica Acta 1999;283:159-169.

Qazzaz HMAM, El-Masri MA, Stolowich NJ, Valdes RJr. Two biologically active isomers of dihydroouabain isolated from commercial preparation. Biochem Bioph Acta 1999;1472:486-497