HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 100/6/1831    most recent 01367.2005v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Stämpfli, H. Articles by Constable, P. D. Search for Related Content PubMed PubMed Citation Articles by Stämpfli, H. Articles by Constable, P. D.

Experimental determination of net protein charge, [A]_tot, and K_a of nonvolatile buffers in bird plasma

¹Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada; and ²Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, Illinois

Submitted 27 October 2005 ; accepted in final form 16 January 2006

The quantitative mechanistic acid-base approach to clinical assessment of acid-base status requires species-specific values for [A]_tot (the total concentration of nonvolatile buffers in plasma) and K_a (the effective dissociation constant for weak acids in plasma). The aim of this study was to determine [A]_tot and K_a values for plasma in domestic pigeons. Plasma from 12 healthy commercial domestic pigeons was tonometered with 20% CO₂ at 37°C. Plasma pH, PCO₂, and plasma concentrations of strong cations (Na, K, Ca), strong anions (Cl, L-lactate), and nonvolatile buffer ions (total protein, albumin, phosphate) were measured over a pH range of 6.8–7.7. Strong ion difference (SID) (SID₅ = Na + K + Ca – Cl – lactate) was used to calculate [A]_tot and K_a from the measured pH and PCO₂ and SID₅. Mean (±SD) values for bird plasma were as follows: [A]_tot = 7.76 ± 2.15 mmol/l (equivalent to 0.32 mmol/g of total protein, 0.51 mmol/g of albumin, 0.23 mmol/g of total solids); K_a = 2.15 ± 1.15 x 10^–7; and pK_a = 6.67. The net protein charge at normal pH (7.43) was estimated to be 6 meq/l; this value indicates that pigeon plasma has a much lower anion gap value than mammals after adjusting for high mean L-lactate concentrations induced by restraint during blood sampling. This finding indicates that plasma proteins in pigeons have a much lower net anion charge than mammalian plasma protein. An incidental finding was that total protein concentration measured by a multianalyzer system was consistently lower than the value for total solids measured by refractometer.

plasma pH; strong ion difference; anion gap; metabolic acidosis

This article has been cited by other articles:

				I. Kurtz, J. Kraut, V. Ornekian, and M. K. Nguyen Acid-base analysis: a critique of the Stewart and bicarbonate-centered approaches Am J Physiol Renal Physiol, May 1, 2008; 294(5): F1009 - F1031. [Abstract] [Full Text] [PDF]

				J. W. George Comments on "Experimental determination of net protein charge, [A]tot, and Ka of nonvolatile buffers in bird plasma" J Appl Physiol, June 1, 2007; 102(6): 2416 - 2416. [Full Text] [PDF]