6 research outputs found
False positive acetaminophen concentrations in patients with liver injury
AbstractBackgroundAcetaminophen toxicity is the most common form of acute liver failure in the U.S. After acetaminophen overdoses, quantitation of plasma acetaminophen can aid in predicting severity of injury. However, recent case reports have suggested that acetaminophen concentrations may be falsely increased in the presence of hyperbilirubinemia.MethodsWe tested sera obtained from 43 patients with acute liver failure, mostly unrelated to acetaminophen, utilizing 6 different acetaminophen quantitation systems to determine the significance of this effect. In 36 of the 43 samples with bilirubin concentrations ranging from 1.0–61.5 mg/dl no acetaminophen was detectable by gas chromatography-mass spectroscopy. These 36 samples were then utilized to test the performance characteristics of 2 immunoassay and 4 enzymatic–colorimetric methods.ResultsThree of four colorimetric methods demonstrated ‘detectable’ values for acetaminophen in from 4 to 27 of the 36 negative samples, low concentration positive values being observed when serum bilirubin concentrations exceeded 10 mg/dl. By contrast, the 2 immunoassay methods (EMIT, FPIA) were virtually unaffected. The false positive values obtained were, in general, proportional to the quantity of bilirubin in the sample. However, prepared samples of normal human serum with added bilirubin showed a dose–response curve for only one of the 4 colorimetric assays.ConclusionsFalse positive acetaminophen tests may result when enzymatic–colorimetric assays are used, most commonly with bilirubin concentrations >10 mg/dl, leading to potential clinical errors in this setting. Bilirubin (or possibly other substances in acute liver failure sera) appears to affect the reliable measurement of acetaminophen, particularly with enzymatic–colorimetric assays
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Rumination, Fear, and Cortisol An In Vivo Study of Interpersonal Transgressions
The authors sought to examine whether rumination about psychologically painful, though nontraumatic, interpersonal transgressions is associated with increased salivary cortisol. They measured salivary cortisol, rumination about a transgression, fear and anger regarding the transgressor, perceived painfulness of the transgression, and positive and negative mood in 115 undergraduates who had experienced an interpersonal transgression during the previous 7 days. They obtained measurements on as many as 5 occasions separated by approximately 14 days each. On occasions when participants reported that they had been ruminating to a degree that was greater than was typical for them, they had higher levels of salivary cortisol than was typical for them. The rumination-cortisol association appeared to be mediated by fear of the transgressor. Rumination about even moderately painful but nontraumatic life events and associated emotions are related to biological changes that may subserve social goals such as avoiding social threats. Items from the rumination scale are appended
Platelet MAO activity and the dexamethasone suppression test in depressed patients
Platelet monoamine oxidase (MAO) activity and postdexamethasone cortisol levels were determined in 26 depressed patients. The incidence of cortisol nonsuppression and the mean postdexamethasone cortisol levels were significantly higher in patients with high MAO activity than in those with low MAO activity