Pulmonary wedge catheterization during positive end-expiratory pressure ventilation in the dog

In ten supine anesthetized dogs, recordings of left atrial (LA) and pulmonary-artery wedge (PW) pressures were simultaneously obtained at several levels of positive end-expiratory pressure (PEEP) ventilation with the thorax either open or closed. Lateral roentgenograms were taken to determine the relative vertical positions of the LA and PW catheter tips. When the wedge catheter tip was vertically above the left artrial catheter tip, mean PW followed airway pressure at PEEP of more that 5 cm H20. For PEEP 5 cm H20 or less, and for PW catheter tip positions vertically below the LA catheter tip at all levels of PEEP, mean wedge catheter pressure was close to left atrial pressure. Thus, it appears the LA pressure can best be estimated by PW catheter positions vertically below the left atrium during positive end-expiratory pressure ventilation.

E1Cold cytotoxic antibodies in kidney graft recipients

Serial serum samples from 39 renal allograft recipients were screened for cold and warm cytotoxic antibodies before and after grafting. In the group of patients who developed antibodies only after grafting, 6 had cytotoxins reactive at 37 degree C and 5 had cytotoxins reactive at 15 degree. At one year, all the patients with cold alloantibodies has functioning grafts, but none of the patients with warm antibodies had kept their graft. In three patients with cold antibodies, the cytotoxins reacted with a subpopulation of cells enriched in B lymphocytes but not with T cells eluted from nylon wool columns. This suggests that certain kinds of antibodies which appear in the blood after grafting may have enhancing properties.

Structure of human high density lipoprotein reassembled in vitro. Radioimmunoassay studies

Immunologic approaches to studying lipoprotein structure have been limited because the methods have not been quantitative enough. Recently we reported (Schonfeld, G., and Pfleger, B. (1974) J. Clin. Invest. 54, 236-246) a radioimmunoassay for human apoprotein A-1 (ApoA-I). Only 8% of the ApoA-I of high density lipoprotein (HDL) reacted in the radioimmunoassay system consisting of rabbit anti-human ApoA-I, 125I-ApoA-I, and unlabeled ApoA-I. We suggested that the ApoA-I in HDL were poorly reactive in the radioimmunoassay because they were "masked" by lipid- or protein-protein interactions. To test this, "lipoproteins" were reconstituted from lipids and apoproteins and assayed for their reactivity in the radioimmunoassay. Apo-HDL, ApoA-I alone, or ApoA-I + ApoA-II were sonified with lecithin or with lipids extracted from HDL. Sonicates were fractionated by ultracentrifugation or by Sepharose 4B chromatography. HDLs were also made by incubating dispersed lecithin or lecithin + cholesterol with Apo-HDL, ApoA-I, or ApoA-II. The lipoproteins were analyzed for lipids and protein chemically. Apoprotein compositions were determined by polyacrylamide disc gel electrophoresis. ApoA-I content by radioimmunoassay then was compared with the ApoA-I content obtained by disc gel electrophoresis. Most reconstituted "lipoproteins" had less than the expected ApoA-I contents. Discrepancies between ApoA-I contents were greatest for lipoproteins prepared from Apo-HDL and HDL-lipids (20 to 30% of expected contents). Discrepancies were smaller for particles prepared with lecithin, with ApoA-I alone or with ApoA-I + ApoA-II (40 to 85% of expected). HDLs made by incubation were less reactive than those prepared by sonication. Thus, the reactivity of ApoA-I in the radioimmunoassay could be diminished by causing it to interact with lipids or their apoproteins, or both, suggesting that antigenic sites became masked. From this one can extrapolate that the poor reactivity of the ApoA-I in HDL isolated from plasma also may have been due to the masking of some of its antigenic determinants. The identification of the determinants involved awaits the development of radioimmunoassays for specific regions of ApoA-I.

Effects of swimming on dystrophic Syrian hamster heart

Morphological and histopathological heart changes were determined for sixteen dystrophic Syrian hamsters (B10 14.6 strain) and sixteen normal hamsters. Eight animals were randomly assigned to each of the following groups: dystrophic swim (DYS-SWM), dystrophic sedentary (DSY-SED), normal swim (NOR-SWM), and normal sedentary (NOR-SED). The daily swimming program consisted of an initial 30-minute swim which was gradually extended to 60 minutes by the end of eight weeks. Weights up to 3% body weight were attached during swimming to increase the work load. Sedentary animals received no experimental treatment. Four animals in each group were sacrificed at 4 and 8 weeks after the initiation of treatments. In comparison with the two groups of sedentary animals, the NOR-SWM group had a greater heart weight/body weight ratio at both 4 and 8 weeks (P less than .05), while the DYS-SWM group had an increased ratio only at 8 weeks (P less than .05). Subjective histopathological evaluation of heart lesions showed that the DYS-SED group had many large areas of inflammatory reaction with infrequent diffuse areas of calcification. In contrast, the DYS-SWM group had fewer and smaller areas of inflammatory reaction with moderate amounts of calcification.

University-Industry Interaction Patterns

The nation is entering a period when the R & D output must be increased, probably without major increases in resource allocation. Obviously, in this situation, either efficiency or productivity must be increased. Perhaps one of the most wasteful aspects of the national R & D system (and one that received little attention during the golden era of the 15 percent per year expansion) has been the very weak coupling between the university, on the one hand, and industry (or government), on the other. It is a serious error to allege about such coupling that "it has never worked," that the objectives and reward structures of the institutions are such that it cannot work, and so on. The fact is that coupling has never been tried seriously. History shows that the total dollar effort in research that required coupling or that had coupling as its main objective was on the order of $10 million per year (that is, much less than 0.1 percent of the research money spent on U.S. campuses). At the same time, there is little doubt that the experiments which must and will be tried in the immediate future call for innovations in management and changes in the attitude and structure of many universities. In conversations with administrators who have had experience with such programs, I have found strong suggestions of very mixed responses from the universities. In light of these responses, and if effectiveness is a goal, it would be better for those universities that are more wedded to disciplinary research, to single principal-investigator work, not to participate in these new efforts. We need much greater diversity in the styles of university life, and it would be healthy for the academic enterprise if some universities retained a greater degree of detachment from society, while others consciously decided to interact more with it, through the private sector, and made the changes necessary to do so. If initial funding is restricted to those universities that consider university-industry or university-government research a worthy objective and that have a proven track record and a favorable administrative and reward structure, the new programs may well establish a major new pattern of national R & D.

The Design of Non-Linear Scales for Slide Rules

Many school children experience considerable difficulty in reading the 0 scale on conventional slide rules. This investigation sets out to provide design recommendations for a scale of acceptable accuracy which can be understood by children with a wide range of abilities. Eight different scale designs, including the conventional design, were compared at a scale-reading task using secondary modern schoolboys as subjects. The scales were presented in booklet form. Errors in the results are classified as either gross errors, i.e. those caused by misunderstanding, or interpolation errors. Analysis shows that the simplest designs, i.e. those with the fewest gradations and numerals, lead to fewer gross errors, and can be read faster than the conventional design. The simpler designs, however, led to more interpolation errors than the conventional design mainly because interpolation errors were not possible (for three significant figure accuracy) at the lower end of the conventional scales. Inconsistency in the meaning of gradations and numerals in different parts of the scale seems to be the main source of misunderstanding on the conventional design. The recommended scale has gradations at the 0.1 positions and numbering only at the 1,2…10 positions. It is suggested, however, that the introduction of such a simplified scale for school slide rides might meet with some resistance, and a scale with consistent numbering and with gradations at the 0.05 position is recommended as a more acceptable alternative.