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51.
A C Bakke J D Gray W Abo F P Quismorio A Lash S M Cooper D A Horwitz 《Journal of immunology (Baltimore, Md. : 1950)》1986,136(4):1253-1259
By using the OKM1 monoclonal antibody and the fluorescence-activated cell sorter to identify lymphocytes bearing iC3b (type 3) complement receptors, two principal populations of OKM1+ lymphocytes have been identified in human peripheral blood. One subset exhibited azurophilic granules and Fc receptors for IgG stained by Leu-11. The other population did not display FcR, but was enriched in cells reacting with OKT3 and OKT8 (low intensity). In healthy subjects, approximately 60% of CR3+ lymphocytes were granular FcR-bearing cells and only 18% co-expressed OKT3 determinants. In patients with systemic lupus erythematosus (SLE), CR3+ lymphocytes were predominantly FcR negative cells and 71% lacked granules. Only 33% reacted with Leu-11, but 50% co-expressed OKT3, 44% reacted with OKT8+, and 15% were OKT4+. We tested the hypothesis that agranular OKT3+ Leu-11- lymphocytes, such as those found in SLE patients, contained the precursors of natural killer (NK) cells. Leu-11+ cells were removed from normal lymphocytes by complement lysis, and the remaining cells were treated with recombinant IFN-alpha, IFN-gamma, or IL 2. These procedures were ineffective in generating typical NK effector cells. Our studies do not support the hypothesis that CR3+ Leu-11- lymphocytes are the precursors of granular Leu-11+ NK cells. 相似文献
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53.
Properties of mixed dispersions of sphingomyelin and the nonionic detergent, Triton X-305, were investigated by analytical ultracentrifugation and by autocorrelation spectroscopy of scattered laser light. These properties were compared with those of the sphingomyelin/Triton X-100 mixed micellar system reported previously [S. Yedgar, Y. Barenholz, and V. G. Cooper (1974) Biochim. Biophys. Acta 363, 98-111]. The substitution of the 30-unit ethylene oxide chain of Triton X-305 for the 10-unit chain of the Triton X-100 resulted in the appearance of two micellar phases at all detergent/lipid mixture ratios studied, whereas only a single mixed micellar phase was observed using Triton X-100. Despite this difference, the properties of the mixed lipid/detergent micelles obtained using Triton X-100 have been verified in the following respects: The detergent aggregation numbers in the mixed micelles are quite constant over a wide range of detergent molar fractions, being about 70 and 400 for the lighter and heavier mixed micellar phases, respectively. The detergent aggregation numbers are larger in the mixed micelle than in the pure detergent micelle. Very large sphingomyelin aggregation numbers can be accommodated within the mixed micelles, apparently by the critical intervention of the detergent molecules to produce a stable micellar structure. 相似文献
54.
T F Tedder M D Cooper L T Clement 《Journal of immunology (Baltimore, Md. : 1950)》1985,134(5):2989-2994
Two monoclonal antibodies (HB-10 and HB-11), which react with human T, B, and NK cells, identify approximately 50% of the Leu-3+ T helper (TH) cells in adult blood. In the present studies, the functional capabilities of the HB-11+ and HB-11-TH cell subpopulations were examined after purification by fluorescence-activated cell sorting. Both subpopulations proliferated in response to PHA, Con A, PWM, and OKT-3 antibodies. The HB-11+ TH cells gave a minimal proliferative response to soluble tetanus toxoid antigen, whereas HB-11-TH cells responded well. After mitogen activation, both HB-11+ and HB-11-TH cells and to produce soluble factors which induce large B cells to proliferate. However, PWM-stimulated HB-11+TH cells were incapable of inducing B cells to differentiate into antibody-secreting plasma cells, whereas HB-11-TH cells were efficient in this regard. The results suggest that the HB-11 antigen is expressed on a subpopulation of virgin TH cells that can produce B cell growth factors but are deficient in the ability to produce B cell differentiation factors. 相似文献
55.
H E Broxmeyer S Cooper B Y Rubin M W Taylor 《Journal of immunology (Baltimore, Md. : 1950)》1985,135(4):2502-2506
The influences of human interferons--natural gamma (2 X 10(7) NIH reference U/mg), recombinant gamma (approximately 5 X 10(6) U/mg), natural alpha (1.4 X 10(8) international reference U/mg), and natural beta (10(6) international reference U/mg)--were evaluated alone or in combination for their effects in vitro on colony formation by low density human bone marrow granulocyte-macrophage (CFU-GM), erythroid (BFU-E), and multipotential (CFU-GEMM) progenitor cells incubated at 5% CO2 in normal incubator (approximately 20%) O2 tension or low (5%) O2 tension. Alone, these interferons demonstrated the same dose response inhibitory curves, as we reported previously, when cells were grown at 20% O2. Recombinant IFN-gamma gave the same dose response curve as natural IFN-gamma. Natural or recombinant interferon synergized with IFN-alpha to suppress colony formation at concentrations that were approximately 2 log units lower than that required by either interferon alone. Equal concentrations of these interferons were not needed for the synergistic effect and were still apparent when one was present at concentrations of 2 log units less than the other. IFN-gamma synergized to a lesser extent with IFN-beta, but IFN-alpha did not synergize with IFN-beta. Cells grown at 5% O2 were more sensitive to inhibition by 2 log units less IFN-gamma or IFN-alpha, and this effect was additive with the synergistic effects of IFN-gamma and IFN-alpha together. These results may have physiological, pathological, and/or clinical relevance. 相似文献
56.
Summary The palatability of 14 species of woody plant was assessed for three species of browsing ruminant, namely kudus, impalas and goats. Results show that palatability was most clearly related to leaf contents of condensed tannins. The effect was a threshold one, with all plants containing more than 5% condensed tannins being rejected as food during the wet season period. In contrast palatability was not influenced by concentrations of protein-precipitating polyphenols, and only weakly related to contents of nitrogen, phosphorus, cations, fibre components and other secondary metabolites. Insect herbivory shows a different pattern. These findings support the hypotheses that (i) condensed tannins function to protect plant cell walls against microbial attack; (ii) hydrolyzable tannins function to inactivate the digestive enzymes of insect herbivores. Large mammalian herbivores are influenced by condensed tannins due to their dependance upon microbial fermentation of plant cell walls for part of their energy needs. 相似文献
57.
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59.
Paul D. Cooper Arthur M. Jungreis 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1985,155(6):743-750
Summary Moulting fluid ofManduca sexta contains high concentrations of potassium and bicarbonate (100 mM) and low concentrations of chloride (5 mM). This fluid begins to disappear from the exuvial space approximately 9–10 h before the actual shedding of the integument. During this time, the integument can be isolated in an Ussing cell and electrical properties measured in vitro. In a normal 32 mM KHCO3 saline, potential difference (PD) is around 10 mV, exuvial side positive, and short-circuit current (SCC) is 15–20 A cm–2. Substitution of chloride slightly reduces both PD and SCC, although resistance does not change significantly. Measurement of chloride transport in the absence of K+ indicates that 100% of the SCC can be accounted for by the net chloride flux (2 A cm–2). TheK
m andJ
max for transepithelial chloride transport are 14 mM and 0.1 Eq cm–2 h–1. Bilateral potassium addition stimulates chloride transport, doubling net chloride flux as potassium concentration increases from 2 to 5 mM. Chloride net flux is not inhibited by the presence of furosemide (1 mM), nor in HCO
3
–
-free saline by thiocyanate (1 or 10 mM) or acetazolamide (0.1 mM), but is inhibited by 100% N2. The pattern of chloride transport inM. sexta is similar to that previously reported for the rectum of locusts. As chloride is normally at low concentrations in the moulting fluid, it is suggested that this transport system acts to maintain low intracellular concentrations which may be necessary for enzymatic functions in the epidermal cells and has little importance in fluid transport.Abbreviations
PD
potential difference
-
PPI
pharate pupal integument
-
SCC
short circuit current
In the time since this research was performed, A.M. Jungreis passed away. He will be missed by his friends and colleagues 相似文献
60.
Summary It has already been demonstrated that model water-in-kerosene systems and toluene diluted heavy crude oil emulsions can be broken by microbial agents. In this studyN. amarae andR. rhodochrous are used on undiluted, water-in-heavy crude oil emulsions. The high viscosity of the undiluted emulsions severely limits the demulsifying ability of the bacteria towards these field emulsions. 相似文献