Biomedical subjects
Publications and source records attributed to S Green.
Aggressive management of severe burns minimizes contractures and helps to maintain muscle tone, joint function and psychological well-being. The positioning, activity and exercise programs, splinting and bandaging, and skin care of burned children carried out by the burns team at the Hospital for Sick Children, Toronto is outlined.
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Tumor necrosis can be induced in transplanted mouse methylcholanthrene-induced sarcoma by a tumor necrosis factor in the serum of mice infected with bacillus Calmette-Guérin and given bacterial endotoxin. Sera from normal mice, endotoxin-treated mice, and mice infected with bacillus Calmette-Guérin do not contain this factor. A 20- to 30-fold purification of the serum factor has been achieved by (NH4)2SO4 fractionation, Sephadex G-100 and G-200 gel filtration, and preparative polyacrylamide electrophoresis. Tumor necrosis factor is not bacterial endotoxin. It migrates with alpha-globulins, is made up of at least four subunits, and has a molecular weight of about 150,000. The active factor is a glycoprotein that contains sialic acid and galactosamine.
Protocols are described for the dominant lethal and in vivo cytogenetics test in rats and the host-mediated assay, using Salmonella typhimurium and Saccharomyces cerevisiae in mice, as used by the Food and Drug Administration in its mutagenicity review of substances from the generally recognized as safe (GRAS) list. In addition proctolols are described for in vitro mutagenicity tests with S. typhimurium and S. cerevisiae and for statistical treatment for evaluation of data from dominant lethal tests.
In planning for the discharge from foster care of children in one-parent families, the potential of fathers is often neglected. An agency study indicates that intensive casework and adequate services can make the return to fathers appropriate.
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In studying "hemorrhagic necrosis" of tumors produced by endotoxin, it was found that the serum of bacillus Calmette--Guerin (BCG)-infected mice treated with endotoxin contains a substance (tumor necrosis factor; TNF) which mimics the tumor necrotic action of endotoxin itself. TNF-positive serum is as effective as endotoxin itself in causing necrosis of the sarcoma Meth A and other transplanted tumors. A variety of tests indicate that TNF is not residual endotoxin, but a factor released from host cells, probably macrophages, by endotoxin. Corynebacteria and Zymosan, which like BCG induce hyperplasia of the reticulo-endothelial system, can substitute for BCG in priming mice for release of TNF by endotoxin. TNF is toxic in vitro for two neoplastic cell lines; it is not toxic for mouse embryo cultures. We propose that TNF mediates endotoxin-induced tumor necrosis, and that it may be responsible for the suppression of transformed cells by activated macrophages.
Investigations of the mutagenicity of hycanthone methanesulfonate (HCT) in mammals have led to varied results. To avoid ambiguous interpretation of significant results previously reported in two dominant-lethal studies of HCT a nested analysis of variance was performed on the number of corpora lutea per pregnant female, the number of implantations per pregnant female, average preimplantation losses, the number of dead implants per pregnant female, and the number of live implants. The analysis showed that variability among males and females was not responsible for the reported significant effects and consequently established the validity of the previous studies. Based on a comparison of the mammalian mutagenicity work performed utilizing hycanthone, pharmacokinetic factors are thought to be responsible for the differences seen; consideration of these factors in the future may lead to fewer false-negative results in mammalian systems.
Differences were detected by ear in vocalizations made during artificial feeding of Japanese monkey troops at three locations. Tape recording and sound spectrographic analysis confirmed a distinctive vocal pattern specific to each site and used only in the provisioning situation. The 3 different acoustic morphologies are variations on a shared tonal theme. Vocal learning by Macaca fuscata may have occurred separately at each site regulated by species-wide constraints on vocal production.
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The haematological role of the spleen has been investigated in a series of 22 patients with active chronic hepatitis. Severe pancytopenia occurred in one patient after three years of steroid therapy and this episode was associated with an increase in spleen size and a high splenic index of red cell destruction. Although the spleen was usually enlarged in the remainder of treated and untreated patients no others showed increased splenic haemolysis. The red cell survival was slightly reduced in most patients but splenic pooling of red cells and expansion of the plasma volume did not significantly reduce the haematocrit level. No consistent haematological differences were detected between the untreated and the treated patients.
The effects of the type of reinforcer on auditory sensitivity and equal-loudness data were determined in the squirrel monkey. The monkeys, restrained and provided with earphones, were conditioned to depress and hold a bar down in the presence of a stimulus light and then to terminate the holding response after onset of a tone. In Experiment 1, the specified behavior sequence postponed electric shock; in Experiment 2, a food reinforcer was dependent on bar release during the tone. The shape of the auditory sensitivity function and the acuity level at each frequency were the same for the two procedures. The audible frequency range extended from below 0.125 kHz (lowest frequency used) to 46 kHz. Sensitivity was maximum at 8 kHz. Latency of bar release following tone onset served as the basic data for constructing a family of equal-loudness contours. The type of reinforcer appeared not to be a determinant of either the shape of individual loudness contours or the pattern of family of equal-loudness functions. At the lower sound-pressure levels, the equal-loudness contours closely paralleled the threshold curves. At more-intense levels, the contours tended to flatten and depend less on frequency.
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