Experimental Determination of Net Protein Charge andA_totandK_aof Nonvolatile Buffers in Canine Plasma

Abstract

Acid-base abnormalities frequently are present in sick dogs. The mechanism for an acid-base disturbance can be determined with the simplified strong ion approach, which requires accurate values for the total concentration of plasma nonvolatile buffers (A(tot)) and the effective dissociation constant for plasma weak acids (K(a)). The aims of this study were to experimentally determine A(tot) and K(a) values for canine plasma. Plasma was harvested from 10 healthy dogs; the concentrations of quantitatively important strong ions (Na+, K+, Ca2+, Mg2+, Cl-, L-lactate) and nonvolatile buffer ions (total protein, albumin, phosphate) were determined; and the plasma was tonometered with CO2 at 37 degrees C. Strong ion difference (SID) was calculated from the measured strong ion concentrations, and nonlinear regression was used to estimate values for A(tot) and K(a), which were validated with data from an in vitro and in vivo study. Mean (+/- SD) values for canine plasma were A(tot) = (17.4 +/- 8.6) mM (equivalent to 0.273 mmol/g of total protein or 0.469 mmol/g of albumin); K(a) = (0.17 +/- 0.11) x 10(-7); pK(a) = 7.77. The calculated SID for normal canine plasma (pH = 7.40; P(CO2) = 37 mm Hg; [total protein] = 64 g/L) was 27 mEq/L. The net protein charge for normal canine plasma was 0.25 mEq/g of total protein or 0.42 mEq/g of albumin. Application of the experimentally determined values for A(tot), K(a), and net protein charge should improve understanding of the mechanism for complex acid-base disturbances in dogs.

Evaluation of pulmonary dysfunctions and acid–base imbalances induced by Chlamydia psittaci in a bovine model of respiratory infection

“…This finding supplements our previously reported results identifying LBP (lipopolysaccharide binding protein) as a suitable marker of the acute phase in bovines [38,40]. In addition, albumin is the most important buffer in plasma [29]. A tot (Prt) was less affected because of hyper(gamma)globulinaemia, a spontaneous immune response.…”

“…Strong ions are those that dissociate completely at physiologic pH, existing either as strong cations (Na + , K + , Ca 2+ , Mg 2+ ) or strong anions (principally Cl - and L-lactate). The most important measured strong ions are Na + , K + and Cl - , calculated in SIDm 3 [28,29]. …”

The use of elements of the Stewart model (Strong Ion Approach) for the diagnostics of respiratory acidosis on the basis of the calculation of a value of a modified anion gap (AGm) in brachycephalic dogs

“…The authors of this paper also wanted to take part in the ongoing discussion on which method that describes the ABB disorders describes them in the most complete way (Russel et al 1996, Constable 2000, McCullough and Constable 2003, Constable and Stampfli 2005, Siegling-Vlitakis et al 2007, Sławuta and Glińska-Suchocka 2012 and, what is important, which one can be applied in everyday veterinary practice. From the clinical point of view, the answer to these questions is not simple.…”

Role of electrolyte abnormalities and unmeasured anions in the metabolic acid‐base abnormalities in dogs with parvoviral enteritis

“…19 Briefly, the strong ion difference was calculated as shown in Table 3, and the A tot was calculated using both albumin and total protein for comparison, because of the fact that globulins have been shown to contribute to the A tot to a greater extent than is seen in humans. 19 Lastly, the SIG was calculated to detect the presence of UA for comparison, with the UA as determined by the FS approach. Four calculations for SIG were used for comparison, based on equations developed for use in canine plasma.…”