Locating the Binding Sites of Pb(II) Ion with Human and Bovine Serum Albumins

Lead is a potent environmental toxin that has accumulated above its natural level as a result of human activity. Pb cation shows major affinity towards protein complexation and it has been used as modulator of protein-membrane interactions. We located the binding sites of Pb(II) with human serum (HSA) and bovine serum albumins (BSA) at physiological conditions, using constant protein concentration and various Pb contents. FTIR, UV-visible, CD, fluorescence and X-ray photoelectron spectroscopic (XPS) methods were used to analyse Pb binding sites, the binding constant and the effect of metal ion complexation on HSA and BSA stability and conformations. Structural analysis showed that Pb binds strongly to HSA and BSA via hydrophilic contacts with overall binding constants of KPb-HSA = 8.2 (±0.8)×104 M−1 and KPb-BSA = 7.5 (±0.7)×104 M−1. The number of bound Pb cation per protein is 0.7 per HSA and BSA complexes. XPS located the binding sites of Pb cation with protein N and O atoms. Pb complexation alters protein conformation by a major reduction of α-helix from 57% (free HSA) to 48% (metal-complex) and 63% (free BSA) to 52% (metal-complex) inducing a partial protein destabilization

A canine model of normovolaemic acute anaemia

The objective was to develop a non-terminal, acute normovolaemic anaemia model in dogs that has minimal effects on patient well-being. Eleven normal Beagle dogs were used. About 20% of the circulating blood volume was removed from the jugular vein 1-3 times per day over a 3-4 day period until a haematocrit (Ht) of 13-17% was obtained. Normovolaemia was maintained by replacing the volume deficit of the red blood cells with Ringer's lactate and re-infusing the plasma. Full blood count and Ht were monitored twice daily. The 13-17% Ht was reached within 3-4 days with the number of phlebotomies ranging from four to seven. The model was primarily developed to determine echocardiographic values as well as Doppler abdominal splanchnic blood flow parameters in anaemic dogs as part of a study that will compare these results to similar studies in babesiosis-induced anaemia. The model may also be useful in the evaluation of the pathophysiology of anaemia in dogs or as a model for anaemia in humans

Association between computed tomographic thoracic injury scores and blood gas and acid–base balance in dogs with blunt thoracic trauma

Objective To determine the association between thoracic injuries evaluated by computed tomography (CT) and arterial blood gas and acid–base status in dogs with blunt thoracic trauma caused by motor vehicle accidents. Design Prospective observational clinical study. Setting University teaching hospital. Animals Thirty‐one client owned traumatized dogs and 15 healthy dogs. Procedures All trauma group dogs underwent a CT scan and simultaneous arterial blood gas analysis within 24 hours, but not before 4 hours, after the traumatic incident within a 45‐month enrollment period. Measurements and Main Results Thorax injuries were classified as pulmonary, pleural space, or rib cage and each of these components was scored for severity using a CT composite pulmonary, pleural, and rib score. The trauma group arterial blood gas and acid–base status were evaluated for statistical difference from the control group. The pulmonary–arterial oxygen pressure was significantly lower in the trauma group compared to the control group that was supported by significant differences in the calculated variables of arterial blood oxygenation as well. There was also a significant correlation between the composite lung score and pleural score and the variables of arterial oxygen status. The pulmonary–arterial carbon dioxide pressure was not significantly different to any of the thoracic injury variables indicating normal alveolar ventilation. Acid–base imbalances were generally mild, insignificant, and variable. Conclusions and Clinical Relevance Blunt thoracic trauma causes significant pulmonary and pleural injury and the blood oxygen economy is significantly affected by this. The functional measures of arterial blood oxygenation were well correlated with thoracic CT pathology. Alveolar ventilation was mostly spared but a clinically significant ventilation perfusion mismatch was present