Recommendations are presented for standardized imaging planes and display conventions for two-dimensional echocardiography in the dog and cat. Three transducer locations ("windows") provide access to consistent imaging planes: the right parasternal location, the left caudal (apical) parasternal location, and the left cranial parasternal location. Recommendations for image display orientations are very similar to those for comparable human cardiac images, with the heart base or cranial aspect of the heart displayed to the examiner's right on the video display. From the right parasternal location, standard views include a long-axis four-chamber view and a long-axis left ventricular outflow view, and short-axis views at the levels of the left ventricular apex, papillary muscles, chordae tendineae, mitral valve, aortic valve, and pulmonary arteries. From the left caudal (apical) location, standard views include long-axis two-chamber and four-chamber views. From the left cranial parasternal location, standard views include a long-axis view of the left ventricular outflow tract and ascending aorta (with variations to image the right atrium and tricuspid valve, and the pulmonary valve and pulmonary artery), and a short-axis view of the aortic root encircled by the right heart. These images are presented by means of idealized line drawings. Adoption of these standards should facilitate consistent performance, recording, teaching, and communicating results of studies obtained by two-dimensional echocardiography. nary Internal Medicine (ACVIM) has recognized the need to adopt profession-wide standards for nomenclature, display and recording, interpretation, communication, and publication of images obtained using this technology. Accordingly, a Committee on Echocardiography, composed of experienced veterinary cardiac ultrasonographers, was formed to produce a report of recommendations for standards in veterinary echocardiography. This report, one of several to be developed by the committee, contains recommendations for standards for routine transthoracic two-dimensional echocardiography (2DE) in the dog and cat. The principles are generally applicable to other species, including horses and other farm animals, but more study and experience will be required before detailed recommendations can be made for these species. The recommendations presented in this report have been reviewed and approved by consensus of the diplomates of the Specialty

Recommendations are presented for standardized imaging planes and display conventions for two‐dimensional echocardiography in the dog and cat. Three transducer locations (“windows”) provide access to consistent imaging planes: the right parasternal location, the left caudal (apical) parasternal location, and the left cranial parasternal location. Recommendations for image display orientations are very similar to those for comparable human cardiac images, with the heart base or cranial aspect of the heart displayed to the examiner's right on the video display. From the right parasternal location, standard views include a long‐axis four‐chamber view and a long‐axis left ventricular outflow view, and short‐axis views at the levels of the left ventricular apex, papillary muscles, chordae tendineae, mitral valve, aortic valve, and pulmonary arteries. From the left caudal (apical) location, standard views include long‐axis two‐chamber and four‐chamber views. From the left cranial parasternal location, standard views include a long‐axis view of the left ventricular outflow tract and ascending aorta (with variations to image the right atrium and tricuspid valve, and the pulmonary valve and pulmonary artery), and a short‐axis view of the aortic root encircled by the right heart. These images are presented by means of idealized line drawings. Adoption of these standards should facilitate consistent performance, recording, teaching, and communicating results of studies obtained by two‐dimensional echocardiography.

DNA polymerase activity was detected in each of eight preparations of concentrated human hepatitis B antigen (HBAg) rich in Dane particles prepared by high-speed centrifugation of antigen-positive human plasma and in none of seven control preparations prepared in the same way from HBAg-negative plasma. The incorporation of 3 H-thymidine-methyl-5′-triphosphate into DNA was dependent on four deoxyribonucleoside triphosphates and MgCl 2 . Treatment of the concentrated HBAg preparations with the nonionic detergent Nonidet P-40 (NP40) more than doubled the enzyme activity. Fractionation of the concentrated HBAg preparation in sucrose density gradients after treatment with NP40 revealed that the enzyme activity appeared within the density range of Dane core antigen but at a slightly higher density than the average for core antigen. The only particles observed by electron microscopy in this region of the gradient were typical 28-nm cores, suggesting that the DNA polymerase activity was associated with a subpopulation of cores. No DNA polymerase activity was found in purified 20-nm HBAg particles. The DNA product of the reaction remained associated with the 110 S core and was not susceptible to DNase digestion when associated with the core. Inhibition of the reaction by actinomycin D and daunomycin suggested that the reaction was dependent on a DNA template associated with the core.