摘要:

The secretion of interferon‐γ (IFN‐γ) by natural killer (NK) cells followingin vitrostimulation with interleukin‐2 (IL‐2) is inhibited by co‐incubation with autologous monocytes at a transcriptional level by more than sixty‐fold. In this study, we investigate the nature of the inhibitory signal and particularly the role of reactive oxygen metabolites (ROMs). It was found that the inhibition of IFN‐γ was operating at a pre‐translational level, this was indicated by the inability of CD 56+‐enriched natural killer cells to accumulate IFN‐γ mRNA in the presence of elutriated monocytes. Both catalase, a scavenger of hydrogen peroxide and histamine, a biogenic amine which inhibits the generation of ROMs by monocytes, strongly abrogated the inhibition of IFN‐γ production. We thereby conclude that histamine behaves synergistically with IL‐2 at a transcriptional level to induce IFN‐γ even in an admi

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0077

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

We have previously reported oscillations in the activities of the phosphoamino acid phosphatases in murine erythroleukaemic cells. In keeping with our predictions we now show that the phosphotyrosine phosphatase activity rhythm has a much shorter period than originally seemed the case, being of the order of 10min and probably less. The periodic changes show evidence of rhythmic modulation of mean, period and amplitude as with all other cellular oscillations studied. Insulin decreases the frequency of the rhythm while the inducer of differentiation, hexamethylene bisacetamide (HMBA) decreases its amplitude. Current ideas on phosphorylation dynamics in relation to metabolism and mitosis may need to be revised in the light of the observations.

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0078

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Early studies, using kinetic methods, suggested that the isozyme pattern of lactate dehydrogenase in various cells oscillated with time. More recent electrophoretic studies on murine erythroleukaemic cells (which exhibit only one isozyme) indicated very high frequency variations (period 2min or less) in the amount of the lone active isozyme. We now show that in HL60 cells, the activity stain intensities of the two major isozyme bands both oscillate but the temporal variations are distinct. As with other cellular rhythms, each of the two periodicities seem to be modulated in cyclic fashion with respect to period, amplitude and mean levels, the periods of both the primary and modulating rhythms being of the order of 10–15min or probably much les

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0079

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

To elucidate in detail the regulatory mechanisms by which the fibronectin mRNA and protein are altered by all‐trans retinoic acid (RA) in bovine lens epithelial (LE) cells, we have investigated the transcription mechanism and the occurrence of nuclear receptors for RA in the nuclei of cultured LE cells. The rate of transcription of fibronectin (FN) mRNA increased by 130% in response to RA. The RA receptors in nuclear extracts prepared from LE cells show specific all‐trans [3H]‐RA binding sites. Saturation binding of all‐trans RA to these receptors and the Scatchard plot analyses of the binding data yielded an apparent dissociation constant (Kd) of about 12nmandBmaxof about 48pmoles/mg protein. Bovine retinoic acid receptors (RARs) have not been reported previously. Our results demonstrate for the first time that RA regulates FN expression and that regulation is at the transcriptional level in LE cells. Thus, retinoids may have an important role in the functional adhesion of epithelium to the lens

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0080

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

A number of recent clinical observations suggest that vitamin D3plays an important role in maintaining normal cardiovascular function, either directly through its receptor in cardiac muscle, or indirectly through its infuence on circulating levels of calcium or on other regulatory factors. By using an antibody directed against the recombinant vitamin D3receptor, we have identified the receptor protein for 1,25(OH)2D3in tissue from two human hearts. The identification of the 1,25(OH)2D3receptor in human heart lends credence to the hypothesis that 1,25(OH)2D3directly effects the human heart and may be involved in several clinically relevant pathological conditions involving the vitamin D3endocrine system.

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0081

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Electrophoretic and kinetic determinations of the activity of lactate dehydrogenase in murine erythroleukaemic (MEL) cells, sampled at 1min intervals, reveal distinct oscillations in the activity and amount of active isozyme. Both oscillations have periods in the range of 2–6min (probably less) and both appear to be rhythmically modulated with respect to period, amplitude and mean. The oscillations also occur in cell‐free systems, a fact which throws doubt on the value of studies where it is assumed that such preparations have constant composit

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0082

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Induction of pinocytosis inAmoeba proteusis independent of adhesion. It is manifested by non‐adhering floating specimens, as well as by amoebae moderately adhering and locomoting on the glass, or tightly attached to the polylysine‐coated substratum. The formation of pinocytotic rosettes results in de‐adhesion, at the beginning of pinocytosis on the glass, but at its end on the polylysine. It suggests an opposition between adhesion and cell shape transformation. Pinocytosis and adhesion are both inhibited, by an unknown mechanism, in the presence of gelatin either in the substratum or in sol

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0083

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

The effects of recombinant Tumor Necrosis Factor α(r‐TNFα) on polyphosphoinositide metabolism were examined in a Burkitt Lymphoma cell line (Daudi cells). After 1h ofin vitrotreatment with r‐TNF α, the incorporation of32Pi into phosphatidylinositol 4,5‐phosphate (PtdInsP2), phosphatidylinositol 4‐phosphate (PtdInsP) and phosphatidylinositol (PtdIns) was reduced compared with controls, confirming previous findings observed in other cell lines of a specific PtdIns breakdown following r‐TNF α treatment. The novelty of this study is therefore the demonstration of early changes in polyphosphoinositide metabolism during the antiproliferative response elicited by this cytokine i

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0084

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0085

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:1065-6995    

DOI:10.1006/cbir.1996.0086

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY