Effect of acute arterio-venous fistulae on mean and phasic coronary flow in the dog.

The effect of acute arterio-venous fistula on mean and phasic coronary flow was studied on 4 open-chest dogs. When the pressure is basically high, after the opening of the fistula the fall which coronary flow shows during the isometric systole occurs to a lesser extent; conversely, when the pressure is basically normal, the fall of the coronary flow may be absent.     

A Comparison of Methods Using Diaminobenzidine (Dab) to Localize Peroxidases in Erythrocytes, Neutrophils, and Peroxidase-Antiperoxidase Complex

Reactions using diaminobenzidine (DAB) to localize the enzyme peroxidase in neutrophils and peroxidase-antiperoxidase (PAP) complex during immunological staining are usually performed in Tris-HCI or phosphate buffer at pH 7.2-7.6. However, DAB solutions at pH 7.2-7.6 often demonstrate erythrocyte pseudoperoxidase as well. By lowering the pH of the DAB solutions, it is possible to selectively suppress the reactivity of pseudoperoxidase while maintaining optimal reactions in neutrophils and PAP complex. For this purpose we recommend ammonium acetate—citric acid buffer at pH 5.5 (pH 5.0-6.0) containing 44 mg DAB per 100 ml buffer and 0.003V-0.03% with respect to H₂O₂.     

Effect of multiple arterial haemorrhage on the coronary circulation

In the open-chest anesthetized dog, multiple arterial haemorrhage induces a reduction of the mean coronary flow, an absote or relative increase of the phasic flow during the early ventricular ejection phase and a decrease during the remaining phases of the cardiac cycle. When blood pressure falls sharply during the haemorrhage, coronary vascular resistance increases, whereas it does not change or decreases when blood pressure falls slowly. Moreover, coronary vascular resistance decreases transiently after the stoppage of the haemorrhage.