Computer analysis of ventricular pressure recordings: evaluation of myocardial contractility on the dog heart in situ]

The contractile indices Vmax (maximum shortening velocity of the contractile element) and ARPD (power averaged rate of power density generation) which have been shown to be unaffected by alterations in preload and afterload were computed from isovolumic left ventricular pressure data of dogs. The two indices were tested for their ability to detect changes in contractility induced by a positive inotropic drug (Isoprenalin). Whereas a good correlation was found between ARPD and Vmax (coefficient of correlation 0,895) the index ARPD was more sensitive to augmentation of myocardial contractility; also because it is simpler to obtain computationally and more appropriate for the intact heart from a theoretical point of view. ARPD should be useful especially for quantification of acute changes in myocardial contractility.     

Down-regulation of murine collagen-induced arthritis by a T cell hybridoma

T cell hybridoma cell lines were generated by somatic cell fusion of BW 5147 myeloma cells and splenic cells from mice suppressed for collagen-induced arthritis (CIA). Two cell lines were characterized for their cell surface phenotype, antigen recognition and capacity to down-regulate the erythema and edema associated with CIA. Cell line T101N was determined to portray the cell surface phenotype Ly1+2- L3T4- Thy1+ by a direct binding assay. Cell line T104B1 was determined to express only the Thy1+ alloantigen. Panning studies, measurement of IL-2 production in vitro and the suppression of antibodies to type I and type II collagen in vivo indicate that the hybridoma cells are not isotype specific in their recognition of the polymorphic interstitial collagens. Down-regulation of the erythema and edema of CIA occurred on injection of 1 X 10(5) T101N cells but not T104B1 cells. Histology of the tarsus region of the hind paw of CIA mice 33 days after the administration of T101N cells showed contrasting histopathology compared to that of CIA mice. The joints of CIA mice given T101N cells showed aligned articular surfaces resembling normal joint structure and only residual pannus. The data indicate that collagen-specific cloned T cell lines can modulate the gross pathology and joint architecture of joints exhibiting CIA.