where 1 mm Hg equals 133 Pa, B.P. is barometricpressure,W.V.P.T iswater vapor pressure at the temperature of equilibration, and ar and a are the absorption coefficients of the gas at the temperature under consideration and at 37 #{176}C. From this relationship, a measured P02 of 187 mm Hg has been predicted (1) for an aqueous solution equilibrated at 24 #{176}C with a gas mixture composed of 21% oxygen, 12% carbon dioxide, and 67% nitrogen. Oxygen, however, does not act independently in this system, and the partial pressures of nitrogen and carbon dioxide at the measurement temperature of 37 #{176}C must be considered. Equation 1 predicts a p N2 and p co2 of 588 and 123mm Hg, respectively. If one includes a water-vapor pressure of 47 mm Hg, the total pressure calculated according to Dalton’s law is 945 mm Hg. Since this exceeds the barometric pressure, the solution must “boil off” gas until the sum of the vapor pressures is again equal to the atmospheric pressure. The difficulty with equation 1 is that it is based on the assumption (2) that the oxygen content of air saturatedwater isunchanged by increasing the temperature. A second phase of gas bubbles will form to accommodate the decreasing gas solubilities as the temperature increases. This phenomenon can be observed by letting a glass of cold water come to ambient temperature on a warm day. Because the gas bubbles formed are in intimate contact with the liquid phase, the partial pressures of the gases in the gas and liquid phases must be equal.Ifthey are not,mass transfer will occur to eliminate any concentration gradients. Consider the equilibration of water with a mixture of gases at temperature T, where T < 37 #{176}C. Let us isolate a 1-ml aliquot of this liquid, and consider its behavior after warming to and equilibration at 37 #{176}C. Let o be the volume of the individual gas in the gas phase, v be the volume of the individual gas in the liquid phase, and V be the total volume of the gas phase. The volume of each gas present in the liquid phase at T is equal to the sum of the volume of that gas present in the liquid phase and the gas phase at 37

Journal Article Effects of hemolysis, icterus, and lipemia on automated immunoassays Get access Kenneth W Ryder, Kenneth W Ryder Department of Pathol., Wishard Memorial Hosp.Indiana Univ. School of Med.1001 W. 10th st.Indianapolis, IN 46202 Search for other works by this author on: Oxford Academic Google Scholar Diana S Trundle, Diana S Trundle Adler Inst. of Lab. Med., Morton Plant Hosp.Clearwater, FL Search for other works by this author on: Oxford Academic Google Scholar Melissa A Bode, Melissa A Bode Department of Pathol., Wishard Memorial Hosp.Indiana Univ. School of Med.1001 W. 10th st.Indianapolis, IN 46202 Search for other works by this author on: Oxford Academic Google Scholar Richard E Cole, Richard E Cole Adler Inst. of Lab. Med., Morton Plant Hosp.Clearwater, FL Search for other works by this author on: Oxford Academic Google Scholar Wells R Moorehead, Wells R Moorehead Department of Pathol., Wishard Memorial Hosp.Indiana Univ. School of Med.1001 W. 10th st.Indianapolis, IN 46202 Search for other works by this author on: Oxford Academic Google Scholar Melvin R Glick Melvin R Glick Department of Pathol., Wishard Memorial Hosp.Indiana Univ. School of Med.1001 W. 10th st.Indianapolis, IN 46202 Search for other works by this author on: Oxford Academic Google Scholar Clinical Chemistry, Volume 37, Issue 6, 1 June 1991, Pages 1134–1135, https://doi.org/10.1093/clinchem/37.6.1134 Published: 01 June 1991

Therapeutic concentrations of methotrexate can cause significant positive interference in cerebrospinal fluid (CSF) protein values when assayed in the Du Pont aca. Conversely, our modified turbidimetric method, in which trichloroacetic acid (TCA) plus a sample blank containing dilute hydrochloric acid is used in place of TCA, exhibits little or no interference from methotrexate. This was verified by assaying solutions that contained a constant amount of protein (approximately 430 mg/L) and various amounts of methotrexate (0.0-2.3 x 10(-4) mol/L) by both the Du Pont aca and the manual turbidimetric method. As expected, the aca results showed increasing protein values with increasing methotrexate, whereas the manual method gave results approximating the expected protein value irrespective of the methotrexate concentration.

Journal Article Improved method for emergency screening for ethylene glycol in serum. Get access M L Ochs, M L Ochs Dept. of Pathol., Indiana Univ. School of Med., Indianapolis 46223 Search for other works by this author on: Oxford Academic Google Scholar M R Glick, M R Glick Dept. of Pathol., Indiana Univ. School of Med., Indianapolis 46223 Search for other works by this author on: Oxford Academic Google Scholar K W Ryder, K W Ryder Dept. of Pathol., Indiana Univ. School of Med., Indianapolis 46223 Search for other works by this author on: Oxford Academic Google Scholar W R Moorehead W R Moorehead Dept. of Pathol., Indiana Univ. School of Med., Indianapolis 46223 Search for other works by this author on: Oxford Academic Google Scholar Clinical Chemistry, Volume 34, Issue 7, 1 July 1988, Pages 1507–1508, https://doi.org/10.1093/clinchem/34.7.1507 Published: 01 July 1988

Serum from a patient with Cushing's syndrome who was being treated with mitotane contained components that interfered with determination of cholesterol in the Du Pont aca. A measured concentration of cholesterol of 4.19 g/L in the undiluted serum increased to a calculated concentration of 9.50 g/L in diluted serum. Adding additional cholesterol oxidase (EC 1.1.3.6) overcame the reaction inhibition in the undiluted sample; adding additional cholesterol esterase (EC 3.1.1.13) had no effect. There is the potential for clinically significant underestimation of cholesterol with the aca in such patients, because the interference may remain undetected. On the other hand, the aca accurately quantified undiluted specimens containing as much as 10 g of cholesterol per liter when mitotane was not present.

Journal Article Sulfasalazine interference in total protein measurements with the Du Pont aca. Get access A T Moriarty, A T Moriarty Search for other works by this author on: Oxford Academic Google Scholar W R Moorehead, W R Moorehead Search for other works by this author on: Oxford Academic Google Scholar K W Ryder, K W Ryder Search for other works by this author on: Oxford Academic Google Scholar T O Oei T O Oei Search for other works by this author on: Oxford Academic Google Scholar Clinical Chemistry, Volume 29, Issue 3, 1 March 1983, Page 592, https://doi.org/10.1093/clinchem/29.3.592 Published: 01 March 1983

Journal Article Evaluation of bromcresol purple method for albumin as used with the aca. Get access D D Davey, D D Davey Search for other works by this author on: Oxford Academic Google Scholar T Austin, T Austin Search for other works by this author on: Oxford Academic Google Scholar W R Moorehead, W R Moorehead Search for other works by this author on: Oxford Academic Google Scholar T O Oei T O Oei Search for other works by this author on: Oxford Academic Google Scholar Clinical Chemistry, Volume 29, Issue 8, 1 August 1983, Pages 1564–1565, https://doi.org/10.1093/clinchem/29.8.1564a Published: 01 August 1983

Examination of 19 serum biochemical and hematologic parameters in a group of white male runners, ranging in age from 23 to 47 years, just prior to and immediately after a 13-mile "mini-marathon," demonstrated a significant increase, by paired Student t-test, in mean values of: K+, BUN, creatinine, CK, LDH, AST (SGOT), alkaline phosphatase, bilirubin, uric acid and leukocyte counts. Prevailing environmental conditions were such as to produce no significant hemoconcentration. Using this group's statistics and this hospital laboratory's upper limits of normal, the percentage of values above two SDs are, for the resting state: K+ 7%, BUN 7%, creatinine 0%, CK 21%, LDH 21%, AST 0%, alkaline phosphatase 0%, bilirubin 7%, uric acid 7%, and leukocyte count 0%. Post-exertional values above normal limits are: K+ 7%, BUN 21%, creatinine 21%, CK 93%, LDH 86%, AST 0%, alkaline phosphatase 0%, bilirubin 14%, uric acid 36%, and leukocyte 71%. Consequently, abnormally high values for K+, BUN, creatinine, CK, LDH, bilirubin, uric acid, and leukocyte counts can often be expected in some patients who exercise heavily. The degree of the abnormality will depend on the level and length of exercise as well as the elapsed time between exercise and testing.

Journal Article A Manual Colorimetric Assay of Triglycerides in Serum Get access Homer G Biggs, Homer G Biggs Department of Clinical Pathology, Indiana University School of Medicine, Indianapolis, Ind. 46202 Search for other works by this author on: Oxford Academic Google Scholar John M Erikson, John M Erikson Department of Clinical Pathology, Indiana University School of Medicine, Indianapolis, Ind. 46202 Search for other works by this author on: Oxford Academic Google Scholar Wells R Moorehead Wells R Moorehead Department of Clinical Pathology, Indiana University School of Medicine, Indianapolis, Ind. 46202 Search for other works by this author on: Oxford Academic Google Scholar Clinical Chemistry, Volume 21, Issue 3, 1 March 1975, Pages 437–441, https://doi.org/10.1093/clinchem/21.3.437 Published: 01 March 1975

Journal Article Colorimetry of Serum Cholesterol with Use of Ferric Acetate/ Uranyl Acetate and Ferrous Sulfate/Sulfuric Acid Reagents Get access David H Jung, David H Jung Indiana University School of Medicine, Indianapolis, Ind. 46202 Search for other works by this author on: Oxford Academic Google Scholar Homer G Biggs, Homer G Biggs Indiana University School of Medicine, Indianapolis, Ind. 46202 Search for other works by this author on: Oxford Academic Google Scholar Wells R Moorehead Wells R Moorehead Indiana University School of Medicine, Indianapolis, Ind. 46202 Search for other works by this author on: Oxford Academic Google Scholar Clinical Chemistry, Volume 21, Issue 10, 1 September 1975, Pages 1526–1530, https://doi.org/10.1093/clinchem/21.10.1526 Published: 01 September 1975