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971.
C Ramos I Sch?dtler-Siwon L Ortiz-Ortiz 《Journal of immunology (Baltimore, Md. : 1950)》1979,122(4):1243-1247
Infection with Trypanosoma cruzi decreases the ability of spleen cells from mice to respond to either T cell, concanavalin A (Con A), or B cell, lipopolysaccharide (LPS), mitogens. The effect of infection on the mitogenic response depends on the elapsed time between the day of infection and the time of mitogen presentation. Responses early in infection are normal, whereas later responses to either mitogen are depressed. Spleen cells from late trypanosome-infected mice inhibit the ability of normal spleen cells to respond to Con A or LPS. The cell in the T. cruzi-infected spleen cells responsible for this effect is nonadherent, sensitive to treatment with anti-mouse thymus serum plus complement, but insensitive to treatment with anti-immunoglobulin plus complement. These data indicate that infection with T. cruzi elicits over time the generation of T cells suppressive to T and B cell mitogenic responses. 相似文献
972.
Pronounced inhibition of noradrenaline uptake by 10-hydroxymetabolites of nortriptyline 总被引:1,自引:0,他引:1
The potency of the tricyclic antidepressant nortriptyline (NT) relative to that of its major metabolite (E-10-hydroxynortriptyline; E-10-OH-NT) to inhibit the uptake of noradrenaline in rat brain slices incubated in human plasma was 1.75 ± S.D. 0.30. The E- and Z-isomers of 10-OH-NT were equipotent. Hydroxy-metabolites of NT or amitriptyline did not inhibited the neuronal uptake of serotonin.During treatment of 87 patients with NT or amitriptyline the mean ratio between the plasma levels of unconjugated 10-OH-NT and NT was 1.40 ± S.D. 0.86 with a range of 0.32 – 5.0. This ratio increased with age. There was a significant correlation between the plasma levels of the two compounds (r = 0.63; p < 0.001). In three patients treated with NT, the CSF levels of the parent drug and unconjugated 10-OH-NT were similar and about 5 % of the plasma levels.These results indicate that during treatment with NT (or amitriptyline) 10-OH-NT contributes to the effect of these drugs on central noradrenergic neurons. This seems to be of special significance in the elderly. 相似文献
973.
Summary A saturator of small dimensions is described. Moist air with dewpoint temperatures ranging from 2°C to 30°C with a long-term stability of ±0.05°C and a maximum output of 400 1/h can be attained.Special attention is paid to the calibration procedure and to the effect of the reduction of dewpoint temperature of moist air flowing through a tube. 相似文献
974.
Water permeability of plant cuticles: The effect of temperature on diffusion of water 总被引:10,自引:0,他引:10
The effect of temperature on water permeability of plant cuticles (astomatous Citrus leaf cuticles) has been investigated. The Arrhenius plot (logarithm of the permeability coefficient vs. 1/temperature) has two linear portions that intersect at 44° C. Evidence is presented to show that this intersection represents the solid/liquid phase transition of cuticular lipids. As the Arrhenius plot has only one phase transition in the temperature range of 5 to 80° C, it appears that all soluble cuticular lipids in the cuticle are present as a homogeneous mixture rather than as individual layers differing in composition. This view is supported by electron spin resonance evidence showing homogenous distribution of spin label fatty acids. The original distribution of soluble cuticular lipids is irreversibly altered by heating cuticular membranes above the transition temperature. This is accompanied by an irreversible increase in water peremeability, demonstrating the importance of the structure of cuticular lipids with regard to cuticular permeability.Abbreviations CM
cuticular membranes
- MX
polymer matrix
- SCL
soluble cuticular lipids
- MES
morpholinoethane sulphonic acid
- J
flux
- ESR
electron spin resonance
- THO
tritiated water 相似文献
975.
Water permeability and composition of soluble cuticular lipids of isolated cuticular membranes from leaves of Citrus aurantium L. were investigated for 3 successive years. The average water permeability coefficient determined using 169 cuticular membranes was 1.09·10–7 cm s–1 with a standard deviation of 0.78·10–7 cm s–1. There were no significant differences in water permeability between years. Cuticular membranes are characterized by a great variability in water permeability both within and between years. Both water permeability of individual membranes and variability between membranes are shown to be determined by soluble cuticular lipids contained within the cuticular membranes. The soluble cuticular lipids of Citrus leaves are composed of fatty acids, primary alcohols, esters, and hydrocarbons. They occur in amounts of 9.84 g cm–2, which represents approx. 3% of the total mass of isolated cuticular membranes. The specific weight of cuticular membranes (365.4 g cm–1) and total amount of soluble cuticular lipids did not vary significantly between years. Significant differences were observed for the amounts and composition of the constituent classes of lipids. Six homologues comprise 86% of the fatty acids (C16; C18; C19; C21; C24; C26), 83% of the primary alcohols (C24; C26; C28; C30; C32; C34) and 88% of the esters (C36; C38; C40; C41; C42; C44). Eleven major homologues amount only to 62% of the total hydrocarbons (C16; C17; C18; C20; C26; C27; C29; C30; C31; C32; C33). Variability in the composition of soluble cuticular lipids between years was much smaller than variability of water permeability and, therefore, no relation between composition of soluble cuticular lipids and water permeability could be found. It is suggested that this may be due to the fact that the lipid composition observed represents the averages of 20 to 30 membranes analyzed so that differences between individual membranes may have been leveled out.Abbreviations CM
cuticular membranes
- MX
polymer matrix
- Pd
permeability coefficient for diffusion of water
- SCL
soluble cuticular lipids
- MES
morpholinoethane sulphonic acid 相似文献
976.
Summary The growth of strains of fibroblasts derived from patients with neurofibromatosis (NF) was compared with that of strains from appropriate controls in culture medium containing 1% or 15% fetal calf serum. The means of the ratios of final to initial cell numbers do not differ significantly between NF strains and control strains. Weakly significant differences are, however, obtained after conversion of the results to mean numbers of cell population doublings, the NF strains showing the higher numbers. The ratios of final to initial amounts of protein also differ significantly under both sets of growth conditions. High growth parameters occur significantly more frequently among our smaple of 11 NF strains than among our sample of 13 control strains. The possibility of the expression of the NF genotype(s) on the level of the cultured fibroblast-like cells and the possible causes of the large ranges of inter-and intra-individual variations of the results are discussed. 相似文献
977.
978.
Stanley A. Robrish Claes-Göran Emilson Christopher W. Kemp Doreen Eberlein William H. Bowen 《Current microbiology》1981,5(6):343-347
The effects of three antimicrobial agents on smooth surface dental plaque in monkeys were assessed using a plaque index, bacterial viable count, and adenine nucleotide analysis. The effects of the agents were revealed equally well when, viability was assayed by extractable adenosine triphosphate (ATP) or conventional viable cell counts. A persistent effect of one of the agents was revealed by both viable count and extractable ATP. These interpretations were supported by calculations of adenylate energy charge from the adenine nucleotide content of the smooth surface dental plaque samples. 相似文献
979.
Arthopyrenia endobrya from Southern Brazil is illustrated and described as a new species of lichens. The thallus is composed of filamentous green algae loosely surrounded by fungal hyphae. Both symbionts grow endophytically within the leaf cells of two species ofLejeuneaceae (Hepaticae). The algae and hyphae penetrate the cell walls of the host by means of fine perforations. The ascocarps develop between the leaves and perforate them with their apical region. The classification as a member of the genusArthopyrenia is preliminary. 相似文献
980.