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991.
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Stefanie Stanzer Birgit Janesch Thomas Augustin Thomas Bauernhofer 《Cellular immunology》2010,261(2):99-104
To address the question whether the higher onset of apoptosis of circulating NK cell subsets might be activation induced in cancer patients, surface expression of NKG2D and serum (s) levels of MHC class I chain-related (MIC) proteins in relation to apoptosis marker and CD95 expression on NK cells were evaluated.Patients showed a significantly higher onset of spontaneous apoptosis of CD56dim NK cells. No difference in the CD95 expression could be detected between patients and normal controls (NCs). Patients’ CD56bright NK cells demonstrated a higher expression of NKG2D compared to CD56dim NK cells. The sMICB levels showed a higher level in patients versus NCs. No correlation between sMIC protein levels with both NKG2D expression and onset of spontaneous apoptosis of NK cell subsets was found.Our data suggest that the higher onset of apoptosis of circulating NK cell subsets of patients is not triggered by activation-induced cell death. 相似文献
995.
W. Rathmayer S. Djokaj 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2000,186(3):287-298
Presynaptic inhibition exerted by the common inhibitor on the closer and opener muscles and by the specific inhibitor on
the opener muscle was investigated in the crab Eriphia spinifrons. In the closer muscle, activation of GABAB receptors by baclofen reduced the mean quantal content of excitatory junctional currents by about 25%. Blocking GABAB receptors with CGP 55845 diminished presynaptic inhibition at a similar percentage. GABAB receptor-mediated presynaptic inhibition is linked to G proteins. Application of pertussis toxin eliminated about 25% of
the inhibition exerted by the common inhibitory neuron. GABAB receptors participate in presynaptic inhibition at release boutons of the slow and the fast closer excitor at a similar percentage.
In the opener muscle, presynaptic inhibition of transmitter release from the same endings of the opener excitor was about
15% stronger with the specific inhibitor than with the common inhibitor. About 10% of the presynaptic inhibition produced
by either one of the two inhibitors could be abolished by blocking GABAB receptors. The amplitudes of the excitatory junctional currents in the opener were reduced in the presence of baclofen by
about 25%, suggesting that synaptic terminals of the opener excitor are endowed with a similar percentage of GABAB receptors as terminals of the slow and the fast closer excitors. Baclofen had no effect on postsynaptic inhibition, indicating
that GABAB receptors are not involved in postsynaptic neuromuscular inhibition.
Accepted: 8 January 2000 相似文献
996.
Migration is energetically demanding and physiologically challenging. Migrating birds, for example, need to boost their antioxidant defenses to defeat the pro‐oxidants produced during high energetic activity. The enhanced antioxidant defense possibly withdraws limited resources (e.g., energy or micronutrients) from other physiological functions, such as immune defense. Such a trade‐off might not occur outside the migration seasons or in resident individuals. Here, we investigate whether there is a negative relationship between innate immune function and antioxidant defense by sampling both migrating and resident blackbirds (Turdus merula) at the same location during the same period of the annual cycle. We show that in migrating blackbirds microbial killing capacity (BKA), an integrative measure of baseline innate immune function was negatively correlated with total nonenzymatic antioxidant capacity. In contrast, in resident conspecifics, sampled at the same time and location, these two physiological measures were not correlated. This suggests that migrating birds trade off innate immune function and antioxidant defense. Furthermore, and likely a consequence of this trade‐off, in migrant blackbirds BKA was positively correlated with oxidative damage to lipids. In resident blackbirds BKA and degree of lipid oxidation were uncorrelated. The mechanism and currencies of the supposed trade‐off are currently unknown, but energetic investments or micronutrients are likely candidates. Future experimental studies could provide more conclusive evidence for this trade‐off; yet, our results open up a new level of thinking about the physiological costs of migration. 相似文献
997.
J. P. DUBEY 《The Journal of eukaryotic microbiology》1978,25(3):380-382
SYNOPSIS. The effect of pretreatment with Isospora felis and bacillus Calmette-Guérin (BCG) on the reexcretion of Toxoplasma gondii occysts was studied in 16 coccidia-free cats. The following conclusions were drawn: (A) Chronically T. gondii-infected cats reexcreted T. gondii oocysts after superinfection with I. felis, and this reexcretion was prevented in cats infected with I. felis before T. gondii infection. (B) Administration of BCG before Toxoplasma infection had no apparent effect on the outcome of the infection. 相似文献
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Johannes J. Volwerk John A. Koke Peter B. Wetherwax O.Hayes Griffith 《FEMS microbiology letters》1989,61(3):237-241
Phosphatidylinositol-specific phospholipase C was purified from the culture medium of B. thuringiensis to high specific activity using a procedure we recently described for purification of PI-PLC from B. cereus (Volwerk et al. (1989) J. Cell. Biochem. 39, 315-325). The purified enzymes from B. thuringiensis and B. cereus have similar specific activities towards hydrolysis of the membrane lipid phosphatidylinositol, and also towards hydrolysis of the glycosyl-phosphatidylinositol-containing membrane anchor of bovine erythrocyte acetylcholinesterase. These results indicate very similar catalytic properties for the structurally homologous PI-specific phospholipases C secreted by these bacilli. 相似文献
1000.
The construction of a plasmid vector, pVT25, which allows an efficient and direct selection for transformed cells carrying recombinant plasmids is described. In this vector, the replicon and ApR gene from plasmid pBR327 are fused to the colE3 gene of pColE3-CA38, whereby positive selection is based on the inactivation of the lethal colicin E3 by the insertion of a foreign DNA fragment. However, pVT25 can be maintained within the Escherichia coli cells when complemented with another plasmid, pVT26, which expresses the colicin E3 immunity (imm) and the TcR phenotypes. Furthermore, pVT25 was used to regulate the expression of the synthetic human proinsulin gene fused to the colE3 gene at the single ClaI site. The production of the characteristic C-peptide of proinsulin, monitored by radioimmunoassay, was shown to be under the control of the inducible promoter of the colE3 gene. 相似文献