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1.
In a variety of tumour systems, individuals carrying progressively growing neoplasms have lymphoid cells with a specific cytotoxic effect on cultured tumour cells from the same individual1–4. Since the sera of tumour-bearing individuals have been shown to prevent tumour cell destruction by immune lymphocytes in vitro2,5–8 and since this serum blocking activity appears early in primary and transplant tumour development5,7, it has been suggested that the appearance of this serum blocking activity might be responsible for the progressive growth of tumours in individuals having cytotoxic lymphocytes. Counteraction of this blocking activity would thus be of primary importance in facilitating the function of an already existing or bolstered cell-mediated immunity. The serum blocking activity might be inhibited in various ways, by preventing the formation of blocking antibody or by interfering with its action (“unblocking”), as demonstrated in Moloney sarcoma regressor sera9. This type of serum also has a therapeutic effect on Moloney sarcomas in vivo10,11, which has been tentatively attributed to its unblocking activity8,9 or, possibly, to a complement-dependent cytotoxicity10. Tumour growth in the Moloney sarcoma system, however, might be due in part to continuous recruitment of neoplastic cells by virus-induced transformation and so the therapeutic effect could be due to a virus-neutralizing serum activity9,10. 相似文献
2.
3.
Effect of Thioacetamide on Rat Liver Regeneration : II. Nuclear RNA in Mitosis 总被引:7,自引:5,他引:2
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The effect of thioacetamide on dividing cells of regenerating rat liver has been studied. Rats were given daily subcutaneous injections of thioacetamide as a 1 per cent solution at a dosage of 5 mg./100 gm. body weight for 7 to 10 days, subjected to partial hepatectomy, and sacrificed 28 to 31 hours later. Thioacetamide treatment results in striking increases in the nuclear ribonucleoproteins of the liver cell without affecting the mitotic rate during regeneration (14). During mitosis, RNA-containing particles were seen within the spindle and coating the contracted chromosomes from prophase through metaphase or early anaphase. At telophase, prior to the reconstruction of the nuclear membrane, fine RNA-containing granules appeared within the compact chromosomal groups. These coalesced to form nucleoli corresponding in number to the number of nucleolar organizer regions. The nuclei and nucleoli showed a rapid increase in size during the reconstruction period when compared with corresponding figures of the control liver samples. Electron micrographs of interphase nucleoli indicated a similar basic granular structure in both drug-treated and control animals. The question is raised as to whether the increased nucleolar material merely made visible some of the nucleolar-chromosomal associations that normally occur in mitosis, or whether thioacetamide directly affects the synthetic activity of the contracted mitotic chromosomes. 相似文献
4.
On the mechanism of ATP-induced shape changes in the human erythrocyte membranes: the role of ATP
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In the preceding paper (Sheetz, M. and S.J. Singer. 1977. J Cell Biol. 73:638-646) it was shown that erythrocyte ghosts undergo pronounced shape changes in the presence of mg-ATP. The biochemical effects of the action of ATP are herein examined. The biochemical effects of the action of ATP are herein examined. Phosphorylation by ATP of spectrin component 2 of the erythrocyte membrane is known to occur. We have shown that it is only membrane protein that is significantly phosphorylated under the conditions where the shape changes are produced. The extent of this phosphorylation rises with increasing ATP concentration, reaching nearly 1 mol phosphoryle group per mole of component 2 at 8mM ATP. Most of this phosphorylation appears to occur at a single site on the protein molecule, according to cyanogen bromide peptide cleavage experiments. The degree of phosphorylation of component 2 is apparently also regulated by a membrane-bound protein phosphatase. This activity can be demonstrated in erythrocyte ghosts prepared from intact cells prelabeled with [(32)P]phosphate. In addition to the phosphorylation of component 2, some phosphorylation of lipids, mainly of phosphatidylinositol, is also known to occur. The ghost shape changes are, however, shown to be correlated with the degree of phosphorylation of component 2. In such experiment, the incorporation of exogenous phosphatases into ghosts reversed the shape changes produced by ATP, or by the membrane-intercalating drug chlorpromazine. The results obtained in this and the preceding paper are consistent with the proposal that the erythrocyte membrane possesses kinase and phosphates activities which produce phosphorylation and dephosphorylation of a specific site on spectrin component 2 molecules; the steady-state level of this phosphorylation regulates the structural state of the spectrin complex on the cytoplasmic surface of the membrane, which in turn exerts an important control on the shape of the cell. 相似文献
5.
Gold salts and phenylbutazone selectively inhibit the synthesis of PGF2α and PGE2 respectively. Lowered production of one prostaglandin species is accompanied by an increased production of the other. Selective inhibition by these drugs was observed in the presence of adrenaline, reduced glutathione and copper sulphate under conditions when most anti-inflammatory compounds inhibited PGE2 and PGF2α syntheses equally. It is postulated that selective inhibitors may have a different mode of action
and beneficial effects may be related to the endogenous ratio of PGE to PGF required for normal function. 相似文献
6.
Myoung Suk Choi Soojin Park Taewon Choi Gihyun Lee Kyoung-Keun Haam Moo-Chang Hong Byung-Il Min Hyunsu Bae 《Cytokine》2013,61(1):256-265
Asthma is a potentially life-threatening inflammatory disease of the lung characterized by the presence of large numbers of CD4+ T cells. These cells produce the Th2 and Th17 cytokines that are thought to orchestrate the inflammation associated with asthma. Bee venom (BV) has traditionally been used to relieve pain and to treat chronic inflammatory diseases. Recent reports have suggested that BV might be an effective treatment for allergic diseases. However, there are still unanswered questions related to the efficacy of BV therapy in treating asthma and its therapeutic mechanism. In this study, we evaluated whether BV could inhibit asthma and whether BV inhibition of asthma could be correlated with regulatory T cells (Treg) activity. We found that BV treatment increased Treg populations and suppressed the production of Th1, Th2 and Th17-related cytokines in an in vitro culture system, including IL2, IL4, and IL17. Interestingly, production of IL10, an anti-inflammatory cytokine secreted by Tregs, was significantly augmented by BV treatment. We next evaluated the effects of BV treatment on allergic asthma in an ovalbumin (OVA)-induced mouse model of allergic asthma. Cellular profiling of the bronchoalveolar lavage (BAL) and histopathologic analysis demonstrated that peribronchial and perivascular inflammatory cell infiltrates were significantly lowered following BV treatment. BV also ameliorated airway hyperresponsiveness, a hallmark symptom of asthma. In addition, IL4 and IL13 levels in the BAL fluid were decreased in the BV treated group. Surprisingly, the beneficial effects of BV treatment on asthma were eradicated following Treg depletion by anti-CD25 antibody injection, suggesting that the major therapeutic targets of BV were Tregs. These results indicate that BV efficiently diminishes bronchial inflammation in an OVA-induced allergic asthma murine model, and that this effect might correlate with Tregs, which play an important role in maintaining immune homeostasis and suppressing the function of other T cells to limit the immune response. These results also suggest that BV has potential therapeutic value for controlling allergic asthma responses. 相似文献
7.
8.
Pasquier CM; Promponas VI; Varvayannis NJ; Hamodrakas SJ 《Bioinformatics (Oxford, England)》1998,14(8):749-750
Summary : FT is a tool written in C++, which implements the Fourier
analysis method to locate periodicities in aminoacid or DNA sequences. It
is provided for free public use on a WWW server with a Java interface.
Availability : The server address is http://o2.db. uoa.gr/FT Contact :
shamodr@atlas.uoa.gr
相似文献
9.
[Purpose]
The purpose of this study is to examine the effects of six-weeks of endurance swim training and short-term intake of Rg1 on the expression of related proteins as well as improvement of aerobic exercise capacity in 8-week-old male SD rats.[Methods]
The groups were divided into placebo (NP, n=6), Rg1 (NRG, n=6), exercise+placebo (EP, n=7), and exercise+Rg1 (ERG, n=7). On completion of the 6-week swimming exercise, Rg1-intake groups were treated with acute uptakes (3 times within 24hrs) of Rg1. After the treatment, all groups were subjected to a swim to exhaustion test, and then the mass of muscle tissue, mRNA expression level and activity of citrate synthase (CS) were analyzed on plantaris.[Results]
There were no differences in the effect of 6-week swimming exercise and short-term intake of Rg1 on body weight and muscle mass between groups. Although the CS mRNA expression was elevated in the exercise group and combined treatment group, there was no significant difference in CS activity. Acute uptakes of Rg1 did not affect swimming time to exhaustion, but it was increased by 235% and 314% by the 6-weeks of exercise and combined treatment of exercise and Rg1, respectively, which suggests that the combined treatment increased the effect on the capacity of aerobic exercise.[Conclusion]
Based on these results, it was confirmed that even a short-term treatment of Rg1 can give an additive effect for improvement of exercise function, and additional studies are needed for the mechanisms and modes of its working. 相似文献10.
Amiloride does not alter NaCl avoidance in Fischer-344 rats 总被引:2,自引:2,他引:0
Fischer-344 (F-344) rats differ from other common rat strains in that they
fail to show any preference for NaCl at any concentration in two- bottle
preference tests. Because 100 microM amiloride partially blocks the
NaCl-evoked chorda tympani (CT) response in electrophysiological studies,
we tested NaCl preference (0.068-0.273 M) in F-344 rats with and without
100 microM amiloride solution as the solvent. A third group was tested with
unadulterated NaCl solutions following CT transection. Amiloride had no
significant effect on the NaCl preference-aversion function, whereas CT
transection significantly reduced NaCl avoidance. These results suggest
that the amiloride-sensitive component of the NaCl response is not
necessary for F-344 rats to display avoidance of NaCl, but the entire CT
input is.
相似文献