IVAC PCA pump.
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Analgesia, Patient-Controlled↗
Biomedical subjects
J Elson
Publications and source records attributed to J Elson.
Cellular electrophysiological marker of irreversible ischemic myocardial injury.
Glass microelectrode studies on posterior papillary muscle (PPM) slice preparations from 20 pentobarbital-anesthetized dogs (15 subjected to prior circumflex coronary artery ligation, 5 to sham ligation) have resulted in the definition of an electrophysiological marker of irreversible ischemic injury, namely, findings of areas composed of cells unable to generate a significant resting potential (less than -25) mV), designated "electrically inactive areas." Electrically inactive areas were essentially confined to PPM from dogs with circumflex coronary ligation; the incidence and distribution of the areas was related to duration of ischemia. Correlative phase- and light-microscopic studies demonstrated close correspondence between such areas and morphological evidence of irreversible ischemic injury. Analysis of frequency and distribution of electrically inactive areas permits quantitative assessment of the extent and spatial distribution of irreversible injury. This method has been used to quantitate injury in PPM from dogs that had been subjected to ligation for varying time periods. The potential utility of this method for evaluation of interventions designed to protect against ischemic injury and to assess electrical properties of surviving cells is considered.
Animals↗
Adriamycin-induced cardiac dysrhythmias in an experimental dog model.
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Animals↗
Detection of alloantigens during preimplantation development and early trophoblast differentiation in the mouse by immunoperoxidase labeling.
An immunoperoxidase-labeling technique allowing visualization of antibody binding to the cell surface at the electron microscopical level has been employed an an analysis of H-2 and non-H-2 alloantigen expression on the early mouse embryo. The presence of non-H-2 antigenic determinants has been confirmed on eight-cell, morula, and blastocyst stages of development. Contrary to previous reports, however, low levels of H-2 antigen have also been detected on the blastocyst. This is the earliest stage at which H-2 has been shown to be expressed on the fertilized mouse egg and may reflect the greater resolution of the immunoperoxidase technique. Using two different models to study the critical peri-implantation stages, those of experimentally induced blastocyst activation and blastocyst outgrowth in vitro, it has been demonstrated that antigen loss occurs on the trophectoderm at the time of implantation, and that this is not necessarily dependent upon maternal influence. It is suggested that the loss may be an important factor in the prevention of maternal immune rejection during the establishment of the fetal allograft. The two major components of the early postimplantation conceptus display a striking differential in antigenic status. The embryonic sac shows a high degree of peroxidase labeling, while the ectoplacental cone trophoblast is unlabeled. These findings add support to the concept of antigenic neutrality of the early trophoblast and its role in the maintenance of a normal fetomaternal immunological equilibrium.
Animals↗
Detection of receptors for immunoglobulin on human placenta by EA rosette formation.
Direct evidence for the existence of Fc receptors on the surface of first trimester and term human placental cells has been obtained by the use of an antibody-coated red cell (EA) rosette assay. The modification of a Ficoll density gradient separation procedure for placental cell population in conjunction with dye uptake experiments, cytocentrifuge preparations and cytological analysis has enabled an identification of the rosette-forming cells in the mature placenta as predominantly, if not entirely, syncytiotrophoblastic. The significance of these findings, together with those demonstrating the presence of cell-surface Fc receptors on the chorionic membrane, are considered in relation to the transmission of immunoglobulin from mother to foetus and to the protection of the foetus as an intra-uterine allograft.
Cell Membrane↗
Fc receptors on mouse placenta and yaol sac cells.
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Animals↗
Antiarrhythmic potency of N-acetylprocainamide.
Compared to procainamide in an animal arrhythmic model, the antiarrhythmic potency of the N-acetylated metabolite of procainamide (NAPA) was 92% with respect to dose and 70% with respect to plasma level. The antiarrhythmic effects of combinations of the drugs were additive. Measurements of procainamide and NAPA plasma levels needed to suppress ventricular extrasystoles suggested that both compounds are nearly equipotent in patients as well. The average plasma level required for arrhythmia control in these patients was equivalent to 5.1 mcg/ml procainamide. Since patients on long-term procainamide therapy have plasma concentrations of NAPA that are usually comparable to, and occasionally greater than, their procainamide levels, dose regiments based on procainamide levels alone need revision to include consideration of the levels of this metabolite.
Animals↗