摘要:

AbstractContinuous ambulatory peritoneal dialysis (CAPD) fluid from three patients with chronic renal failure exhibited the activity of colony‐stimulating factor (CSF) in amounts varying from 5 to 40 units per ml. Like the CSF obtained from normal human urine, the peritoneal CSF predominantly produced monocyte/macrophage colonies in soft‐agar culture of mouse bone marrow cells. Semipurified peritoneal CSF showed its isoelectric point at pH 3.6 and 4.9 before and after the treatment with neuraminidase. Under the same conditions, the urinary CSF was focused at pH 3.1 and 4.6. The position of elution of the peritoneal and urinary CSF in ordinary gel‐filtration chromatography corresponded to a molecular weight of 62,000 and 117,000, whereas both CSFs exhibited a molecular weight of 28,000 upon gel‐filtration in the presence of 6 M guanidine HCI. Furthermore, the two CSFs from the human sources were neutralized by antimouse L cell CSF serum in the same manner. We conclude that the peritoneal CSF is a sialoglycoprotein which is nearly identical with the urinary CSF despite processing of the latter through

ISSN:0021-9541    

DOI:10.1002/jcp.1041180102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractTransferrin receptor expression by the human tumour cell lines CCRF‐CEM leukaemia and PMC‐22B melanoma was studied, measuring the specific binding of fluorescein isothiocyanate (FITC)‐labelled transferrin using a fluorescence‐activated cell sorter. By measuring the fluorescence of cells stained at subsaturating concentrations of conjugate it was possible to calculate the average numbers of receptors per cell and the binding affinity by Scatchard analysis. These values (1.9 × 105binding sites/cell, KA1.2 × 109M−1for CCRF‐CEM during exponential growth and 6.9 × 104binding sites/cell, KA1.4 × 10−9M−1for PMC‐22B) are in close agreement with previously published data obtained using radiolabelled transferrin. The present method, however, allowed the transferrin receptor expression of individual cells within a population to be measured and thus it has been possible to test the hypothesis that transferrin receptor is a marker for cycling cells. Frequency‐distribution histograms of transferrin receptor showed a wide range of values for both cell lines during exponential growth. When the extreme ranges were sorted and the cells examined for cellular DNA content it was found that those with the highest transferrin receptor expression were enriched with cells in S, G2, and M phases of the cell cycle, whereas those with low transferrin receptor expression were mainly in G1. However, two‐parameter‐correlated dot plots of transferrin receptor expression versus DNA content showed there was considerable overlap between the ranges of receptor expression for the different cell cycle compartments. Using a stathmokinetic method we have measured the proportion of quiescent cells in fed plateau phase cultures. Transferrin receptor expression was downgraded under these growth conditions but, contrary to expectation, the decline affected the population uniformly, without the emergence of a distinct, transferrin receptor‐negative subpopulation corresponding to the increasing proportion of quiescent cells. Thus, although transferrin receptor expression bears some relation to cell cycle phase and reflects the proliferative activity of populations of cells, it is incapable of identifying individual

ISSN:0021-9541    

DOI:10.1002/jcp.1041180103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe possible involvement of membrane‐bound calcium in the mechanism of action of leukotriene B4was examined using the fluorescent chelate probe, chlortetracycline. Leukotriene B4was found to cause a rapid release of membrane‐bound calcium at physiologically relevant concentrations. This effect of leukotriene B4is stereospecific and its magnitude is decreased upon the transformation of leukotriene B4into its ω‐hydroxy and ω‐carboxy metabolites. The pool of calcium affected by leukotriene B4appears to be the same as that released by other chemotactic factors such as formyl–methionyl–leucyl–phenylalanine (f‐Met‐Leu‐Phe). Similarly, preincubation with f‐Met‐Leu‐Phe results in a decreased responsiveness of the cells to the addition of leukotriene B4. These results extend further the analogy between the mechanism of action of peptidic and lipid chemotactic factors, and emphasize the central role of the intracellular redistribution of calcium, as inferred and monitored by chlortetracycline fluorescence and steady‐state isotopic flux stud

ISSN:0021-9541    

DOI:10.1002/jcp.1041180104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe effect of the steel mutation on spermatogenesis was investigated by using organ culture. Cultured cryptorchid testes from C57BL/6− +/+ mice showed an effective differentiation of type A spermatogonia in response to an increased concentration of bovine serum. In contrast, the cryptorchid testes from C57BL/6 –S/d/ + mice showed only limited differentiation of type A spermatogonia even in the highest concentration of serum tested. The type A spermatogonia of mutant mice showed the normal mitotic response but did not differentiate further. The findings reported here are the first in vitro demonstration of the deleterious effects of the steel mutation on testicular germ cell differentiation and suggest that the effect of the steel mutation is expressed in Sertoli cells, the only supporting element in seminiferous tubules, or germ cells themsel

ISSN:0021-9541    

DOI:10.1002/jcp.1041180105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe relationship between cell cycle and cell density was determined for three different lines of mouse cells by equilbrium centrifugation of suspension cultures. The mean cell densities of the three lines differed significantly, with values of 1.0622, 1.0678, 1.0540 gm/ml for 70Z/3, S 107, and ABE 8, respectively. However, the density distributions within each of the three lines were indistinguishable, with an average coefficient of variation about 5% of the mean reduced density (i.e., density minus one). Quantitative DNA analysis of the cells separated by density showed that the proportion of cells in G1, S, and G2 + M phase of the cell cycle changed very little or not at all with cell density. In addition, cells separated by size (and therefore by phase of the cell cycle) using velocity sedimentation had the same means and distributions of densities. These results indicate that there is little or no change in cell density as the cells traverse the life cycle and that buoyant density appears to be a constant property of a cell type.

ISSN:0021-9541    

DOI:10.1002/jcp.1041180106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractUptake and phosphorylation of externally supplied [3H]‐thymidine are fully stimulated in fertilized sea urchin eggs exposed to 5.0 μg/ml aphidicolin. As in untreated controls, the rate of uptake in aphidicolin‐treated eggs increases greater than 50‐fold shortly after fertilization, and greater than 85% of the transported thymidine is immediately phosphorylated to the triphosphate. The intracellular levels of [3H]‐thymidine triphosphate (3H‐dTTP) resulting from an external supply of [3H]‐thymidine is therefore equal in aphidicolin‐treated and untreated fertilized eggs. Under the same experimental conditions, the incorporation of externally supplied [3H]‐thymidine into newly synthesized DNA of fertilized eggs is 90% inhibited by exposure to aphidicolin. The full availability of3H‐dTTP in these eggs further suggests that aphidicolin inhibits specifically at the level of DNA synthesis. This inhibitory effect is proportional to the concentration of aphidicolin between 0 and 5.0 μg/ml. In the continuous presence of 5.0 μg/ml aphidicolin, fertilized eggs fail to undergo mitotic chromosome condensation, nuclear envelope breakdown, and cytokinesis, suggesting a dependent link between these processes and the completion of n

ISSN:0021-9541    

DOI:10.1002/jcp.1041180107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractIn a family of clonal lines derived from the Reuber H 35 rat hepatoma, four electrophoretically distinct molecular forms of uridine kinase (UK I, II, III, and IV) have been characterized. They are the same as those found in foetal rat liver. Different UK profiles occur in these cell lines, and no strict correlation could be established between the state of differentiation of the cells and the form of UK expressed. A clone of somatic hybrid cells between line p4 (form 1 only) and Fu5‐5 (forms II, III, and IV) that does not express form I indicates that p4 cells may lack a factor controlling the polymerization of form I. This variety of clonal cell lines was used to study the uptake and phosphorylation of labeled uridine. The results suggest a relationship between the UK form present and the rate uridine phosphorylation by the intact cell

ISSN:0021-9541    

DOI:10.1002/jcp.1041180108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractOrnithine decarboxylase (ODC) activity usually rises to a peak a few hours after a trophic stimulus. The stimulation of ODC has been shown to depend on extracellular calcium in several in vitro eukaryotic systems. We have investigated the effect of calcium concentration on ODC activity and have found that ODC is stimulated when CaCl2alone is added to calcium‐deprived cells. Epithelial cells from calf esophagus were cultured and grown until stratified. Replacement of medium with fresh serum‐free medium resulted in stimulation of ODC activity, which peaked at 4 hours and declined to basal level by 10 hours. Subsequent depletion of Ca2+either by addition of ethylene glycol bis (β‐aminoethyl ether) N, N′‐tetraacetic acid (EGTA) or by replacement of medium with Ca2+‐free medium, resulted in obliteration of ODC activity 4 hours later. Conversely, cultures in which medium was replaced with Ca2+‐free medium and at 10 hours were repleted with Ca2+(either by addition of CaCl2or by replacement of medium with Ca2+‐containing medium) exhibited a pronounced elevation of ODC activity 4 hours later. ODC activity peaked at 6 hours after the addition of CaCl2and declined by 8 hours. The effect was elicited by a wide range of concentrations of added Ca2+from 0.1 mM to 4.0 mM, but was maximal at 1.0 mM. ODC activity was totally abolished if either cycloheximide (10 μg/ml) or putrescine (10 mM) was added to cultures immediately prior to Ca2+addition. Actinomycin D (2, 5, or 10 μg/ml) added 30 minutes before Ca2+did not prevent the stimulation of ODC by added Ca2+. Stimulation by Ca2+is dependent on (1) absence of Ca2+during the initial 10‐hour incubation and (2) duration of incubation in Ca2+‐free medium prior to Ca2+replenishment. The results indicate that Ca2+can increase ODC in epithelial cells exposed to Ca2+‐depleted medium and that the increase in ODC depends on protein synthesis but is not in

ISSN:0021-9541    

DOI:10.1002/jcp.1041180109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe properties of spleen colony forming units (CFU‐S) contained in two murine fetal liver cell populations (pre‐colony‐forming cell (CFC) and CFC fractions) obtained after fluorescence‐activated cell sorting fractionation on the basis of pokeweed mitogen binding have been analyzed. Individual spleen colonies generated by both populations were examined to determine cellularity, differential cell morphology, as well as CFU‐S and in vitro CFC content. Spleen colonies from both populations contained approximately equal numbers of cells 7 days after transplantation; at 12 days, however, CFU‐S from the pre‐CFC fraction produced four times as many cells per colony than colonies from the CFC fraction. Although the frequency of spleen colonies containing CFU‐S was similar, in comparison to the CFC fraction, spleen colonies obtained from the pre‐CFC fraction contained higher absolute numbers of CFU‐S. This was most evident with CFU‐S assayed 12 days after transplantation of 12‐day spleen colony cells (pre‐CFC fraction, 84% of colonies contained CFU‐S, mean of 527 per colony; CFC fraction, 77% of colonies contained CFU‐S, mean of 41 per colony). Similarly, the in vitro CFC content of 7‐ or 12‐day spleen colonies was higher in colonies produced by pre‐CFC fraction CFU‐S. No significant differences were observed in either the proportion of CFU‐S in S‐phase or the morphology of spleen co

ISSN:0021-9541    

DOI:10.1002/jcp.1041180110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe rate of consumption of oxygen by V‐79 cells in multicellular spheroids was measured as a function of the spheroid diameter. In situ consumption was equal to that of exponentially growing cells for spheroids less than 200 μm in diameter. The rate of oxygen consumption decreased for cells in spheroids between 200 and 400 μm diameter to a value one‐fourth the initial, then remained constant with further spheroid growth. Comparison of consumption rates for spheroid‐derived cells before and after dissociation from the spheroid structure indicated that the spheroid microenvironment accounted for only 20% of the change in oxygen consumption rate. Cell‐cell contact, cell packing, and cell volume were not critical parameters. Plateau‐phase cells had a fivefold lower rate of oxygen consumption than exponential cells, and it is postulated that the spheroid quiescent cell population accounts for a large part of the intrinsic alteration in oxygen consumption of cells in spheroids. Some other mechanism must be involved in the regulation of cellular oxygen consumption in V‐79 spheroids to account for the remainder of the reduction observed i

ISSN:0021-9541    

DOI:10.1002/jcp.1041180111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY