摘要:

AbstractThe microspectrofluorometric approach has been used to investigate in single living cells in culture fundamental questions raised by the use of anthralin, a potent antipsoriatic drug. This method allows fluorescence determinations on the intracellular fate of the drug as well as the recognition of structural and metabolic alterations induced by the drug. In the absence of demonstrable adduct formation with DNA, the antipsoriatic, i.e. antiproliferative effect of anthralin, has been attributed to its action at the level of mitochondria or at the level of glucose‐6‐phosphate dehydrogenase which initiates the pentose phosphate shunt (cf.its prominent role in nucleic acid synthesis). Upon addition of 2·3 to 23 μManthralin to the L cell culture, the characteristic structure of the anthralin anion fluorescence spectrum is recognized almost immediately in the cytoplasm (much weaker in the nucleus) but disappears within minutes. The vital mitochondrial fluorescence probe dimethylaminostyryl‐pyridinium‐methyl‐iodine reveals striking structural alterations of the mitochondria within 15 min after addition of the drug. At the same time, there is a stimulation of the transient NAD(P)+reduction observed upon microinjection into the L cell of the Krebs' cycle substrate malate, or the pentose cycle substrate 6‐phosphogluconate. Specially, the injection of the latter to anthralin‐treated cells suggests that upon release of the mitochondrial control, there is a tremendous disruption of metabolic activity which could have profound consequences on the proliferative activity of the cell.These findings, while they open new possibilities for the intracellular evaluation of therapeutic agents, create also a challenge in understanding the complex and dynamic interrelationships between intracellular organelles and bioenergetic or biosyn

ISSN:0263-6484    

DOI:10.1002/cbf.290040302

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

摘要:

AbstractA method is described, based on the detection of adipocyte‐specific cell surface antigens, which allows assessement of the relative surface damage incurred by the cells when they are prepared under a variety of conditions. Using the method it is possible to develop, for any set of reagents, a set of cell isolation conditions (collagenase concentration, time of incubation) which will produce minimally damaged cells which exhibit high levels of specific cell surface immunoreactivity. Under certain conditions a recovery from limited surface damage can be achieved, although, when cells are prepared under more extreme conditions irreversible surface damage occurs. The surface morphology of the cells as revealed by scanning electron microscopy, is also clearly affected by the conditions of cell isolation. The method has been used to define the conditions necessary for the isolation of cells to be used in the study of subtle biochemical response

ISSN:0263-6484    

DOI:10.1002/cbf.290040303

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

摘要:

AbstractMouse pancreatic islets culturedin vitrowere infected with a tissue culture‐adapted or a mouse pancreas‐adapted strain of Coxsackie B4 (CB4) virus. The effects of the viruses on the islets were assessed by examination of their biochemical functions. It was found that the mouse pancreas‐adapted strain of CB4 induced a ‘leakage’ of insulin from islets incubated at a basal (2 mmol l−1) glucose concentration, both at two and four days following infection. However, at a stimulatory concentration of glucose (20 mmol l−1) the rate of insulin secretion appeared to be normal in these islets. At two days the rate of total protein synthesis in islets infected with mouse pancreas‐adapted CB4, incubated at high glucose concentration, was reduced; at four days the degree of inhibition was more severe, the rate at basal glucose concentration falling to half that of the control islets and at the stimulatory glucose concentration to a quarter of the control islets. (Pro)insulin biosynthesis was also inhibited, the rate being reduced to less than half the mean control value in islets infected with mouse pancreas‐adapted CB4 virus at 20 mmol l−1glucose at two days; at four days the rate was greatly reduced at both 2 and 20 mmol l−1glucose. It is concluded from this study that (1) only certain strains of CB4 virus can infect mouse pancreatic isletsin vitroand (2) that infection with strains of virus tropic for the islets leads to an impairment of metabolic functions of the B‐cells, and i

ISSN:0263-6484    

DOI:10.1002/cbf.290040304

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

摘要:

AbstractWe have studied the effect of various fractions of foetal bovine serum upon the endogenous degradation of long labelled proteins in cultured MRC5 cells, and upon other cellular functions. Only heat‐inactivated serum was capable of suppressing protein degradation to a similar extent to complete serum. Acid‐treated and delipidized sera were moderately effective. Albumin on its own was able to replace 40 per cent of the effect of serum, indicating the exogenous protein might compete with endogenous protein for degradation in lysosomes. Albumin was not capable of supporting DNA synthesis. Dialysed serum showed an age‐related effect suppressing protein degradation to a lesser extent and being less effective in supporting DNA synthesis or cellular proliferation in aged cells. All the effects noted were related to lysosomal protein degradation. Serum diffusate did not suppress protein degrad

ISSN:0263-6484    

DOI:10.1002/cbf.290040305

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

摘要:

AbstractN‐acetyl‐β‐D‐glucosaminidase (NAG) activity and isoenzyme profiles were studied in myeloid, histiocytic, B‐lymphoid, T‐lymphoid and lymphoblastoid continuous cell lines in order to determine ifN‐acetyl‐β‐D‐glucosaminidase isoenzyme expression may help to distinguish among various types of leukemic proliferation.Total NAG activity in myeloid, histiocytic, erythroleukemic cell lines were higher than Burkitt's lymphoma derived cell lines (B‐lymphoid), T‐ or lymphoblastoid cell lines.On chromatofocusing by PBE 94 coupled with an automated enzyme assay an intermediate (I) β‐N‐acetyl‐glucosaminidase form, eluting between forms B and A, was found in all leukemic and in Epstein‐Barr virus infected lymphoblastoid cell lines analysed.The different profiles recorded, the expression of the I form and the different I/B ratios may be useful

ISSN:0263-6484    

DOI:10.1002/cbf.290040306

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

摘要:

AbstractIn murine thymocytes cyclic nucleotide phosphodiesterase is represented by cAMP‐ and cGMP‐specific forms. cAMP and cGMP phosphodiesterase activities showed anomalous kinetic behaviour indicative of ‘low’ and ‘high’ affinity enzyme forms. Sucrose density gradient centrifugation resolved only ‘low’ affinity forms of cAMP and cGMP phosphodiesterases. Gel filtration on Ultragel Aca 34 column showed that cAMP and cGMP phosphodiesterases are probably oligomeric enzymes. Storage of enzyme preparation at 4°C for 24–48 h led to a decrease of higher molecular weight form and enhancement of cAMP and cGMP phosphodie

ISSN:0263-6484    

DOI:10.1002/cbf.290040307

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

摘要:

AbstractCathepsins B and D, β‐galactosidase, and acid phosphatase activities were found to be decreased in the regenerating rat liver, the reduction being maximal around the peak of hepatocyte mitoses (30 h). To investigate whether these changes could be heterogeneously distributed among hepatic cells, total cell populations from control or two‐thirds hepatectomized rat livers were dissociated by the collagenase perfusion technique and analysed by different procedures. Isopycnic centrifugation in a Metrizamide gradient satisfactorily resolved hepatocytes and non‐parenchymal cells from control animals but was not adequate when applied to 30‐h regenerating liver cells. Colchicine treatment of the hepatectomized animals, resulted in substantial accumulation of phase M‐hepatocytes. Subpopulations considerably enriched in fast‐sedimenting phase M‐cells were obtained by sedimentation at 1gof the total liver cell population, and subsequently analysed by isopycnic equilibration. Phase M‐hepatocytes were shown to have markedly reduced levels of β‐galactosidase, acid phosphatase, and cathepsin B activities in comparison, not only with control hepatocytes, but also with those parenchymal cells which were not metaphase‐arrested in the same regenerating livers. Therefore, in partially‐hepatectomized rats, hepatocytes progressing up to metaphase in the first mitotic cycle exhibited a selective depletion of lysosomal enzyme activities. The mechanism(s) underlying this change rema

ISSN:0263-6484    

DOI:10.1002/cbf.290040308

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

摘要:

AbstractUsing frozen liver sections and quantitative cytochemistry it has been established that when cells are allowed to oxidize a cytoplasmic and a mitochondrial substrate simultaneously the resulting oxidative activity is markedly higher than the sum of the oxidation of each substrate measured separately. In the present study this type of synergistic interaction has been confirmed in the kidney, particularly in cells of the pars recta. Our results support the evidence of the influence of cytoplasmic NADPH on the intramitochondrial oxidative process and it is suggested that, in cells of the pars recta, cytosolic NADPH may be involved in intramitochondrial mixed function oxidases such as 1α‐hydroxylase: these results could further elucidate the mechanism responsible for the production of the hormonal form of vitamine

ISSN:0263-6484    

DOI:10.1002/cbf.290040309

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

ISSN:0263-6484    

DOI:10.1002/cbf.290040311

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY

ISSN:0263-6484    

DOI:10.1002/cbf.290040312

出版商:John Wiley&Sons, Ltd.    

年代:1986

数据来源: WILEY