摘要:

AbstractThe murine macrophage‐like cell line (Mm‐1), which is nonleukemogenic to syngeneic SL mice, was originally derived from spontaneously differentiated cells of a clonal line of mouse myeloid leukemia cells (M1). In the present experiment, variant cell lines with a high (Mm‐A), moderate (Mm‐P), and little or no (Mm‐Sl and Mm‐S2) leukemogenic potential were obtained from the Mm‐1 cells. The mean survival times of syngeneic SL mice inoculated i.p. with 5 × 106Mm‐A and Mm‐P cells were 17 and 33 days, respectively, whereas almost all the mice inoculated with Mm‐S1 or Mm‐S2 cells survived for more than 90 days. These variant cell lines did not lose their macrophage‐like characteristics in vitro. These variant cell lines phagocytized latex beads and sensitized sheep erythrocytes, produced lysozyme, and adhered to culture dishes. The four variant cell lines showed no significant difference in porliferation rates in vitro in liquid medium containing 10% calf serum, but Mm‐A cells could grow both in soft agar medium in the absence of ascitic fluid containing colony‐stimulating factor (CSF) and in liquid medium containing 1% serum, whereas Mm‐P cells could grow in the liquid medium but not in soft agar medium without ascitic fluid, and Mm‐S1 and Mm‐S2 cells could not grow in either medium. The ratio of the nuclear area to the cell area (NCR) of Mm‐A cells was a high (51%) but those of Mm‐Sl and Mm‐S2 cells were low (40–41%), and that of Mm‐P cells was intermediate (44%). The leukemogenicity of Mm‐1 cell lines was roughly correlated with their NCR. The possibility that interactions between Mm‐1 variant cells and host immune cells might be involved in the mechanisms of their different leukemogenicities was not supported by results on the in vitro susceptibilities of Mm‐1 variant cells to the cytostatic actions by normal macrophages and spleen cells and on leukemogenicities of the Mm‐1 variant cells in athymic nude mice. A possible method of control of th

ISSN:0021-9541    

DOI:10.1002/jcp.1041180202

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

年代:1984

数据来源: WILEY

摘要:

AbstractThis study explores the in vitro modulation of the lipid‐filled phenotype of the lipid interstitial cell (LIC) isolated from the developing rat lung. Isolated LIC lose their cytoplasmic lipid droplets when cultured in fetal bovine serum (FBS) but retain their potential for lipid storage, since they rapidly reaccumulate lipid when subcultured in neonatal rat serum (NRS) and to a lesser extent in adult rat serum (ARS). The return of LIC to a lipid‐filled state may not represent cell differentiation, since it occurs in the presence of bromodeoxy‐uridine. NRS contains twice the free fatty acids (FFA) of FBS and ARS, and doubling the FFA concentration of FBS and ARS increases LIC storage lipids. Serum triglyceride (TG) is 10 times higher in ARS and 23 times higher in NRS than in FBS. Since LIC lipoprotein lipase (LPL) activity is in the range of 3T3‐L1 adipocytes (0.56 vs. 1.72 units/mg DNA), the LIC has the potential of incorporating serum lipoprotein‐triglyceride. The LPL activity of LIC is 9–12 times that of fetal and adult rat lung fibroblasts and 50 times that of human lung, trachea, or skin fibroblasts; LIC are probably a source of endothelial LPL in the developing lung. The response of LIC and ARLF cyclic‐AMP to hormones known to influence lipid synthesis or degradation showed that: only LIC responded to glucagon; prostagladin E1was a more potent stimulus to LIC; isoproterenol was a more potent stimulus to ARLF; and neither cell responded to ACTH. The unique nature of LIC tends to support further the concept of fibroblast heterogeneity w

ISSN:0021-9541    

DOI:10.1002/jcp.1041180203

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

年代:1984

数据来源: WILEY

摘要:

AbstractIncubation of transformed mouse fibroblasts with external ATP in alkaline medium low in divalent cations causes an increase in the permeability of the plasma membrane to nucleotides and other small molecules. Previous suggestions that the phosphorylation of a 44,000 dalton membrane protein is involved in this permeabilization process have been pursued. Fractionation of cells that had been incubated with [γ‐32P] ATP revealed that the labeled 44K phosphoprotein was found in both the membrane and mitochondrial fractions. Incubation of fractions isolated from unlabeled cells with [γ‐32P] ATP resulted in substantial formation of32P‐44K in the mitochondrial fraction and less incorporation in the membrane fraction. The 44,000 dalton protein was identified as the α‐subunit of mitochondrial pyruvate dehydrogenase by partial proteolytic mapping and immunological cross‐reactivity with antibodies prepared against bovine pyruvate dehydrogenase. The phosphorylation of this protein in whole cells by externally added ATP is suppressed by inclusion in the incubation medium of carboxyatractyloside (CAT) and EDTA. These substances have no effect on ATP‐dependent permeabilization, indicating that the phosphorylation of pyruvate dehydrogenase is not involved i

ISSN:0021-9541    

DOI:10.1002/jcp.1041180204

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

年代:1984

数据来源: WILEY

摘要:

AbstractProlonged treatment of Swiss 3T3 cells with phorbol 12,13 dibutyrate (PDB) rendered the cells refractory to subsequent mitogenic stimulation by both PDB and vasopressin. In contrast, the cells retained full responsiveness to a wide variety of other mitogens. An early response to vasopressin and phorbol esters, inhibition of (125l)‐labeled epidermal growth factor [(125l)‐EGF] binding, was also substantially decreased in PDB pretreated cells. The cross desensitization was not produced by vasopressin; this ligand induced homologous but not heterologous desensitization. Exposure of Swiss 3T3 cells to PDB caused a down regulation of (3H)‐PDB receptors but did not reduce the binding of vasopressin to refractory cells. The time‐course (t1/2= 7 h) and dependence on PDB concentration (half maximal at 20 nM) for this phorbol ester receptor loss paralleled the induction of the mitogenic desensitizations to both PDB and vasopressin. However, the time‐course of recovery revealed an important dissociation between receptor presence and mitogenic response.When Swiss 3T3 cultures, which had been pretreated with PDB, were washed to remove this ligand and incubated in its absence for 24 h, both (3H)‐PDB receptors and PDB or vasopressin inhibition of (125l)‐EGF binding were almost completely restored to control levels. However the homologous and heterologous mitogenic desensitizations showed a very different reversal time. After a 24‐h recovery period PDB‐treated refractory cells were still unable to synthesize DNA in response to PDB or vasopressin. The mitogenic desensitizations were however completely reversible; after a 48‐h incubation in the absence of PDB the cells responded fully to the mitogenic actions of PDB or vasopressin. This finding suggests that a further postreceptor step was also desensitized by prolonged PDB treatment. The presence of a low level of cycloheximide during the PDB pretreatment blocked induction of this postreceptor refractoriness. We propose that this refractory postreceptor step selectively blocks both PDB and vasopressin stimulation of DNA synthesis and may represent the point at which the mitogenic pathways of phorbol esters and v

ISSN:0021-9541    

DOI:10.1002/jcp.1041180205

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

年代:1984

数据来源: WILEY

摘要:

AbstractContinuous cell lines were derived from primary cultures of adherent bone marrow cells from SJL/J, BALB/c, C3H/eb, RF, and nude‐ICR mice. All these lines readily assumed a pure fibroblastoid appearance with the exception of the BALB/c line (MBA‐14), which retained both fibroblastoid and monocytoid cells. This particular line could promote the proliferation of myeloid progenitors (CFU‐C) in short‐term bone‐marrow cultures. The two cell types that composed the MBA‐14 cell line were successfully isolated and grown separately; the monocytes as the 14M and 14M1 cell lines and the fibroblastoid cells as the 14F clones. The latter were found to be preadipocytes and accumulated fat in the absence of added hydrocortisone, in medium supplemented with fetal calf serum. Growth of the monocyte lines (14M and 14M1) was dependent upon the mononuclear phagocyte stimulator CSF‐1. In the parent MBA‐14 cell line the growth of monocytes seemed to depend upon stimulating factor(s) produced by the fibroblastoid cells. The 14M1 monocytes were able to process and degrade antigen as efficiently as primary macrophages. Furthermore, processed antigen produced by 14M1 cells evoked proliferative response by antigen‐primed lymph‐node cells. In addition to these immunological functions the 14M1 cells were capable of modulating the colony‐stimulating activity and degree of adipogenesis exhibited by the fibroblastoid cells. These interactions between monocytes and fibroblastoid cells may constitute part of the mechanism controlling the activity of the hematopoi

ISSN:0021-9541    

DOI:10.1002/jcp.1041180206

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

年代:1984

数据来源: WILEY

摘要:

AbstractExposure of suspension‐cultured HeLa cells to a 45° thermal shock resulted in cell inactivation and inhibition of both protein and DNA synthesis. DNA synthesis was inhibited in a biphasic manner with a more sensitive (D0= 7 min) and a less sensitive (D0= 20 min) phase. The less sensitive process was demonstrated to be DNA chain elongation. Transport of thymidine into intracellular pools was significantly less sensitive to thermal shock (D0in excess of 200 min). When HeLa cells were heated at 45° for 15 min there was an 80% inhibition of incorporation of precursors into both DNA and protein with little effect on precursor transport into cellular pools. While the rate of synthesis of whole cell and histone protein (H2a, H2b, H3, and H4) and DNA chain elongation recovered by 6 h after cell heating, total precursor incorporation into DNA was only 0.4 of control levels. The long‐term depression of the DNA synthetic rate could not be explained by a cell cycle redistribution, a depression in the total fraction of S phase cells synthesizing DNA, or by a depression in the rate of DNA chain elongation. We conclude that thermal shock results in a long‐term depression in the fraction of cell replicons involved in DNA repl

ISSN:0021-9541    

DOI:10.1002/jcp.1041180207

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

年代:1984

数据来源: WILEY

摘要:

AbstractMorphological and molecular aspects of granulocyte differentiation can be studied concomitantly using liquid cultures of immature granulocytes in conjunction with a newly developed high‐performance liquid chromatographic (HPLC) assay for differentiation proteins. Immature granulocytes, isolated from guinea pig bone marrow by Ficoll density centrifugation, were placed in liquid cultures and incubated for periods up to 1 week. In the presence of 10% dialyzed, normal guinea pig serum, these cells were almost all converted to mature granulocytes, whereas at serum concentrations below 1% mostly macrophages were formed. Cell multiplication does not appear to be necessary for granulocyte maturation in this culture system. The data also show that morphological maturation in vitro is accompanied by the formation of all the major membrane and secondary granule differentiation proteins detected by the HPLC assay in extracts of mature granulocytes formed in vivo. The techniques described here should facilitate the isolation and purification of the factors in normal serum that control the induction of synthesis of these differentiation marker

ISSN:0021-9541    

DOI:10.1002/jcp.1041180208

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

年代:1984

数据来源: WILEY

摘要:

AbstractCirculating macrophages and T lymphocytes can invade the vascular endothelium and migrate from the circulatory system to an extravascular compartment such as inflammatory organs. In an in vitro model system we have examined the capacity of murine T lymphocytes and peritoneal macrophages to attach and invade a confluent vascular endothelial cell monolayer and to degrade sulfated proteoglycans in the subendothelial extracellular matrix.Concanavalin A and antigen‐specific (egg albumin) activated T lymphocytes labeled with [3H]thymidine attached to the apical surface of the vascular endothelium in a time‐dependent manner. A subsequent invasion of the endothelial cell monolayer was observed by scanning electron microscopy. Both activated T lymphocytes and murine macrophages degraded the [35S]O4=‐containing fragments in a process which required cell‐matrix contact but was not dependent on serum proteases.Sulfated glycosaminoglycan chains produced from matrix proteoglycans by treatment with papain or alkaline borohydride were 3–4 times larger than the cell‐mediated degradation fragments. This suggests that both macrophages and T lymphocytes elaborate upon stimulation an endoglicosidase capable of cleaving glycosaminoglycans specifically and releasing heparan sulfate‐rich fragments. The ability of activated cells of the immune system to attach and invade the vascular endothelium and to degrade sulfated proteoglycans is very similar to that reported for highly metastati

ISSN:0021-9541    

DOI:10.1002/jcp.1041180209

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

年代:1984

数据来源: WILEY

摘要:

AbstractA dual‐labelling technique has been used to establish that partial hepatectomy has no effect on the degradation of poly (A)+mRNA and confirms that the increased incorporation of precursor into mRNA during early prereplicative development reflects an actual increase in mRNA biosynthesis. Simultaneous studies on the changes in nuclear RNA metabolism support the conclusion that an increase in gene transcription does occur. Colchicine, at concentrations known to disrupt microtubules, has no effect on this increase in gene transcription but prevents the translation of the gene products by promoting polysome disaggregation transiently during a critical stage of prereplicative development. Studies with mefenamic acid and hydrocortisone, specific inhibitors of prostaglandin metabolism, have ruled out any involvement of prostaglandins in the induction of prereplicative mRNA synthesi

ISSN:0021-9541    

DOI:10.1002/jcp.1041180210

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

年代:1984

数据来源: WILEY

摘要:

AbstractExpression of markers of differentiation was measured in a clone of the continuous cell line K562, derived originally from the cells of a patient with leukemia. Three of the markers were lineage specific, R18 for erythropoiesis and 80H.5 and My‐1 for granulopoiesis. The fourth marker was the self‐renewal capacity of clonogenic cells. The markers were measured as a function of time in pooled colonies from day 2 to day 12, and at a point of time in individual colonies. Evidence of an orderly pattern of marker appearance and disappearance was not seen. Rather, their expression appeared to occur at random during gro

ISSN:0021-9541    

DOI:10.1002/jcp.1041180211

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

年代:1984

数据来源: WILEY