bluuebunny/crossref_metadata_2025_split huggingface dataset:
Volume‐regulating behavior of human platelets
Authors: Livne Avinoam , Grinstein Sergio , Rothstein Aser 
Published: February 2005

AbstractHuman platelets exposed to hypotonic media undergo an initial swelling followed by shrinking (regulatory volume decrease [RVD]). If the RVD is blocked, the degree of swelling is in accord with osmotic behavior. The cells could swell at least threefold without significant lysis. Two methods were used to follow the volume changes, electronic sizing and turbidometery. Changes in shape produced only limited contribution to the measurements. The RVD was very rapid, essentially complete in 2 to 8 minutes, with a rate proportional to the degree of initial cell swelling. RVD involved a loss of KCI via volume‐activated conductive permeability pathways for K+ and anions, presumably Cl −. In media containing > 50 mM KCI, the shrinking was inhibited and with higher concentrations was reversed (secondary swelling), suggesting that it is driven by the net gradient of K+ plus Cl−. The K+pathway was specific for Rb+ and K+ compared to Li+ and Na+. The Cl− pathway accepted NO3− and SCN− but not citrate or SO2‐4. In isotonic medium, the permeability of platelets to Cl− appeared to be low compared to that of K+. After hypotonic swelling both permeabilities were increased, but the Cl− permeability exceeded that of K+. The Cl− conductive pathway remained open as long as the cells were swollen. RVD was incomplete unless amiloride, an inhibitor of Na+ /H+ exchange, was present or unless Na+ was replaced by an impermeant cation. In addition, acidification of the cytoplasm occurred upon cell swelling. This reduction in pHi appeared to activate Na+/ H+ exchange, with a resultant uptake of Na+ and reduction in the rate and amount of shrinking. Like other cells, platelets responded to hypertonic shrinking with activation of Na+/H+ exchange, but regulatory volume increase was not detectable.
Recombinant murine granulocyte‐macrophage (GM) colony‐stimulating factor supports formation of GM and multipotential blast cell colonies in culture: Comparison with the effects of interleukin‐3
Authors: Koike Kenichi , Ogawa Makio , Ihle James N. , Miyake Takaji , Shimizu Tomoe , Miyajima Atsushi , Yokota Takashi , Arai Ken‐Ichi 
Published: February 2005

AbstractWe studied the effects of murine recombinant granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) on murine hemopoiesis in methylcellulose culture. The GM‐CSF was purified from cultures of Saccharomyces cerevisiae transfected with a cloned murine GM‐CSF cDNA. In cultures of spleen cells from normal mice, only granulocyte‐macrophage (GM) colonies were supported by GM‐CSF. Blast cell colonies were the predominant type in cultures of spleen cells from 5‐fluorouracil (5‐FU)‐treated mice. Dose‐response studies revealed that maximal GM and blast cell colony formation is achieved with 100 U/ml GM‐CSF. Blast cell colonies revealed variable but high replating efficiencies, and the secondary colonies included multilineage colonies. Serial replating of washed blast cell colonies in cultures with GM‐CSF provided evidence for the direct effects of GM‐CSF on the proliferation of multipotential blast cells. A combination of GM‐CSF and interleukin‐3 (IL‐3) did not increase the number of blast cell colonies over the level supported by IL‐3. This observation indicates that the progenitors for blast cell colonies that responded to GM‐CSF are a subpopulation of multipotential progenitors that are supported by IL‐3. Cytological studies of colonies derived from GM‐CSF and/or IL‐3 suggest that the eosinophilopoietic ability of murine GM‐CSF is less than that of IL‐3.
Metabolically inactive 3T3 cells can substitute for marrow stromal cells to promote the proliferation and development of multipotent haemopoietic stem cells
Authors: Roberts R. A. , Spooncer E. , Parkinson E. K. , Lord B. I. , Allen T. D. , Dexter T. M. 
Published: February 2005

AbstractWhen highly enriched multipotential spleen colony forming cells (CFU‐S) obtained following fluorescence activated cell sorting (FACS‐CFU‐S) are cultured on marrow stromal cells, they undergo proliferation and development to produce mature haemopoietic cells (Spooncer et al., Nature, 316:62–64, 1985). We now show that FACS‐CFU‐S behave in a similar way when cultured on monolayers of 3T3 cells, indicating that the 3T3 cells can supply at least part of the environment which is representative of marrow stromal cells and provide, therefore, a system for studying stromal cell: haemopoietic cell interactions. We also demonstrate that IL‐3‐dependent multipotential stem cell lines (FDCP‐Mix), but not a variety of other “committed” IL‐3‐dependent cell lines, resemble FACS‐CFU‐S in terms of their ability to proliferate and differentiate when cultured on 3T3 cells in the absence of IL‐3. In this system, attachment of the FDCP‐Mix to the 3T3 cells is critical for the subsequent maintenance of viability and stimulation of development of the cells. When the FDCP‐Mix cells are physically separated from the 3T3 cells, they die and their death cannot be prevented by using 3T3‐cell‐conditioned medium. The extracellular matrix generated by 3T3 cells is not sufficient for promoting attachment or viability of the FDCP‐Mix cells, indicating the importance of integral membrane components. However, attachment and development of FDCP‐Mix cells occurs on 3T3 cells that have been lightly fixed with glutaraldehyde indicating that active metabolism is not essential for the effects promoted by the 3T3 cells. We suggest that the ability of FACS‐CFU‐S and FDCP‐Mix cells to respond to 3T3 cells involves specific ligand/receptor interactions.
Interactions of dimethyl sulfoxide and granulocyte‐macrophage colony‐stimulating factors on the growth and maturation of HL‐60 cells
Authors: Brennan J. K. , Lee K. S. , Abboud C. N. , Erickson‐Miller C. L. , Keng P. C. 
Published: February 2005

AbstractWe have studied the interactions of dimethyl sulfoxide (DMSO), Giant Cell Tumor (GCT) cell‐conditioned medium (GCT CM), and highly purified granulocyte‐macrophage colony‐stimulating factors (GM‐CSF) on the growth and maturation of a highly passaged population of HL‐60 cells. DMSO produced dose‐dependent inhibition of HL‐60 growth in liquid and semisolid media. Growth was partially to completely restored by the addition of GCT CM to cultures. Experiments in which cell volume, cell cycle kinetics, tritiated thymidine (3HTdr) incorporation, cell number, and nitroblue tetrazolium (NBT) reduction were compared during culture indicated that DMSO inhibited the spontaneous increase in cell volume and flow of cells through the cell cycle which occurred in the first day of culture, the increase in 3HTdr incorporation which was detectable by day 2; and the increment in cell counts which occurred by day 3. These effects were opposed by GCT CM. In contrast, the DMSO‐induced increase in NBT reduction which occurred by day 6 was not influenced by GCT CM. The major principle opposing DMSO was GM‐CSF, since (1) highly purified GM‐CSF from GCT cells and recombinant GM‐CSF from COS cells transfected with the Mo cell GM‐CSF gene overcame greater than 50% of DMSO inhibition; and (2) conditioned media from cells not producing CSF, G‐CSF from GCT cells, and recombinant G‐CSF from Escherichia coli transfected with the G‐CSF gene from 5,637 cells were inactive. DMSO had little or no effect on the elaboration of autostimulatory activity by HL‐60 cells. DMSO is a useful agent for inhibiting the spontaneous growth of HL‐60 cells and restoring their dependence on GM‐CSF, a property which may be mediated through the effects of DMSO on cell cycle kinetics and/or maturation.
Quantitative ultrastructural, autoradiographic evidence for the magnitude and early involvement of the Golgi apparatus complex in the endocytosis of wheat germ agglutinin by cultured neuroblastoma
Authors: Mezitis Spyros G. E. , Stieber Anna , Gonatas Nicholas K. 
Published: February 2005

AbstractSeveral ligands undergo endocytosis into the Golgi apparatus. We have examined with a quantitative ultrastructural, autoradiographic method the sequential endocytosis of tritiated wheat germ agglutinin (3H‐WGA) by cultured murine neuroblastoma cells. Cells were incubated with 3H‐WGA for 1 hour at 4°C, washed, and incubated in complete medium without ligand at 37°C for 5, 15, 30, and 120 minutes. At 5 minutes, the optimized sources/μm2 of neuroblastoma cell area, which represented the grain density of each compartment, were as follows: smooth vesicles and tubules, 1.03 ± 0.88; Golgi‐associated vesicles, i.e., clusters of vesicles within a 1 μm radius of the Golgi cisterns, 1.03 ± 0.31; Golgi cisterns, < 0.01; and lysosomes, 0.26 ± 0.16. At 15 minutes grain densities were: smooth vesicles and tubules, 0.9 ± 0.34; Golgi‐associated vesicles, 1.41 ± 0.28; Golgi cisterns, 0.73 ± 0.41; and lysosomes, 0.1 ± 0.09. At 30 minutes grain densities were: smooth vesicles and tubules, 0.46 ± 0.46; Golgi‐associated vesicles, 1.78 ± 0.34; Golgi cisterns, 0.89 ± 0.78; and lysosomes, 0.39 ± 0.14. At 2 hours, smooth vesicles, tubules, and Golgi cisterns were not labeled, Golgi‐associated vesicles were still labeled (0.71 ± 0.1), and lysosomes were heavily labeled (2.17 ± 0.22). These results are consistent with the hypotheses that either the Golgi complex (cisterns and associated vesicles) is an early and intermediate step of the endocytosis of 3H‐WGA into lysosomes or that it constitutes part of a separate and quantitatively significant pathway of endocytosis of this ligand.
Pathways of glutamine and glutamate metabolism in resting and proliferating rat thymocytes: Comparison between free and peptide‐bound glutamine
Authors: Brand Karl , von Hintzenstern Jutta , Langer Klaus , Fekl Werner 
Published: February 2005

AbstractPathways of glutamine metabolism in resting and proliferating rat thymocytes were evaluated by in vitro incubations of freshly prepared or 60‐h cultured cells for 1–2 h with [U14C]glutamine. Complete recovery of glutamine carbons utilized in products allowed quantification of the pathways of glutamine metabolism under the experimental conditions. Partial oxidation of glutamine via 2‐oxoglutarate in a truncated citric acid cycle to CO2 and oxaloacetate, which then was converted to aspartate, accounted for 76 and 69%, respectively, of the glutamine metabolized beyond the stage of glutamate by resting and proliferating thymocytes. Complete oxidation to CO2 in the citric acid cycle via 2‐oxoglutarate dehydrogenase and isocitrate dehydrogenase accounted for 25 and 7%, respectively. In proliferating cells a substantial amount of glutamine carbons was also recovered in pyruvate, alanine, and especially lactate. The main route of glutamine and glutamate entrance into the citric acid cycle via 2‐oxoglutarate in both cells is transamination by aspartate aminotransferase rather than oxidative deamination by glutamate dehydrogenase. In the presence of glucose as second substrate, glutamine utilization and aspartate formation markedly decreased, but complete oxidation of glutamine carbons to CO2 increased to 37 and 23%, respectively, in resting and proliferating cells. The dipeptide, glycyl‐L‐glutamine, which is more stable than free glutamine, can substitute for glutamine in thymocyte cultures at higher concentrations.
Effect of the mi allele on mast cells, basophils, natural killer cells, and osteoclasts in C57BI/6J mice
Authors: Stechschulte Daniel J. , Sharma Ram , Dileepan Kottarappat N. , Simpson Karen M. , Aggarwal Neelam , Clancy John , Jilka Robert L. 
Published: February 2005

AbstractThe osteopetrotic, microphthalmic (mi/mi) mouse lacks functional osteoclasts and has also been reported to be deficient in mast cells and natural‐killer (NK) cells. The later deficiencies could be secondary to the osteopetrotic marrow, or a direct result of the mi allele. Therefore, heterozygotes were examined for these cell types, since these mice do not exhibit osteopetrosis. Adult +/mi animals have approximately 50%, and mi/mi animals examined by histologic techniques or tissue histamine levels have 0–10%, of the peritoneal, dermal, and intestinal mast cells compared with that of +/+ animals. Leukocyte histamine, indicative of the number of basophils, demonstrates the same pattern. Histamine content per mast cell in +/+ and +/mi animals is identical. The number of large granular lymphocytes (LGL) in splenic leukocyte preparations from +/mi animals is 50% that of +/+ animals, and these cells are undetectable in preparations from mi/mi mice. NK activity against YAC‐1 cells paralleled the number of LGL present. The resorptive response of neonatal calvaria to parathyroid hormone was delayed in the case of cultured +/mi bone compared with that of +/+ bone, but the final rate of calcium release was identical. These data indicate that (1) the presence of one mi allele can affect the development of four distinct cell types, and (2) osteopetrosis alone does not account for the lack of mast cells, basophils, and NK cells in mi/mi mice.
Local effects of EGF, α‐TGF, and EGF‐like growth factors on lobuloalveolar development of the mouse mammary gland in vivo
Authors: Vonderhaar Barbara K. 
Published: February 2005

AbstractFive‐week‐old female mice supplemented with estradiol and progesterone are able to respond to epidermal growth factor (EGF) and EGF‐like growth factors (α‐transforming growth factor [α‐TGF] and crude mammary‐derived growth factor) with local lobuloalveolar development when these growth factors are directly introduced into the mammary glands via slow‐release cholesterol‐based pellets. Contralateral glands receiving pellets containing only cholesterol showed no growth response. The local growth effect is maximal at 4–5 days of exposure to hormones and growth factors. The glands appear to be more sensitive to α‐TGF than EGF, since local development is seen with one‐fifth the level of the former vs. the latter growth factor and can be seen even in the absence of the systemic estrogen/progesterone supplement.
Reconstituted basement‐membrane matrix modulates fibroblast activities in vitro
Authors: Emonard H. , Grimaud J. A. , Nusgens B. , Lapière Ch. M. , Foidart J. M. 
Published: February 2005

AbstractCellular growth and collagen biosynthesis were compared in dermal calf fibroblasts cultured on plastic or on a reconstituted basement membrane gel, termed matrigel. This matrix, extracted from Engelbreth‐Holm‐Swarm tumors, consists mainly of laminin, entactin, type IV collagen, and heparan sulfate proteoglycan. The multiplication rate of fibroblasts grown on matrigel was stimulated compared to that of monolayered cells cultured on plastic, and these cells formed multilayers after 4 days. Protein and collagen biosynthesis was reduced in fibroblasts cultured on matrigel. A higher proportion of the newly synthesized collagen (40%) was incorporated to the extracellular matrix in cultures grown on matrigel than in those grown on plastic (14%). Type III collagen was the preferential collagen type deposited on matrigel, and the ratio type III:type I collagens secreted in the medium was also slightly higher in cultures grown on matrigel. Partially processed collagen was more abundant in fibroblasts grown on matrigel than in cells cultured on plastic. Finally, cells grown on matrigel exhibited a higher catabolic activity than cells grown on plastic. In this experimental model, the reconstituted basement‐membrane matrix seems to influence the activities of fibroblasts significantly.
Oxygen and substrate dependence of hepatic cellular respiration: Sinusoidal oxygen gradient and effects of ethanol in isolated perfused liver and hepatocytes
Authors: Kekonen Eija M. , Jauhonen V. Pekka , Hassinen Ilmo E. 
Published: February 2005

AbstractThe oxygen dependence of hepatic cellular respiration was studied by employing simultaneous organ spectrophotometry of cytochromes and hemoglobin, the latter used as an intrasinusoidal optical oxygen probe. The Kmof cytochromeaa3for oxygen was found to be 6.8 μM in the isolated perfused liver and 0.3 μM in suspensions of isolated hepatocytes. The results indicate that the sinusolid‐to‐cell pO2gradient is about 5 torr. Optical determination of the average effective pO2indicates that the axial sinusoidal O2profile does not conform to zero‐order O2uptake in the liver. Because of extensive NAD+reduction, ethanol increases the thermodynamic driving force of oxidative phosphorylation, and it also increased the oxygen consumption in both the perfused liver and the hepatocyte suspension, but had no effect on the grade of steady‐state cytochromeaa3reduction, the cellular energy state [ATP]/[ADP]·[Pi], or the Kmof cytochromeaa3for oxygen. The results indicate that hepatic energy metabolism is oxygen independent at very low O2concentrations, but that the sinusoidal axial O2concentration is anomalous, probably due to the spatial arrangement of the metabolizing systems.
Effect of sodium butyrate on S‐100 protein levels and the cAMP response
Authors: Hirschfeld Alan , Bressler Joseph 
Published: February 2005

AbstractSodium butyrate (NaB), when added to cell cultures, produces a variety of morphological and biochemical changes. We examined its effects, in nM concentrations, on the expression to two glioma cell‐associated proteins, glial fibrillary acidic protein (GFAP) and S‐100 protein in human glioma‐derived cell line (RF), and of S‐100 protein in the C6 rat glioma cell line. GFAP levels decreased by about 50% in the RF cell line, and S‐100 protein levels decreased protein levels decreased by about 40% after treatment with 1 mM NaB for 48 h. In the C6 rat glioma cell line, isoproterenol with theophylline was found to increase S‐100 protein levels by two‐fold over basal levels. NaB was found to inhibit the induction of S‐100 protein but exhibited no effect no effect on the basal levels of the protein. Other short chain fatty acids, including sodium propionate and sodium isobutryate, exhibited partial inhibitory activity. NaB, at an EC50 of 1 mM, was also found to inhibit both the beta‐adrenergic and the forskolin‐mediated increase in cAMP levels in these cells. This suggests that NaB may inhibit cells from expressing S‐100 protein by attenuating cAMP levels.
Mechanism of sucrose uptake by isolated rat hepatocytes
Authors: Sasaki Anna W. , Williams Stuart K. , Jain Mahendra , Wagner Roger C. 
Published: February 2005

AbstractThe transport of molecules by nonspecific endocytosis has been described in many cell types, but it has not been characterized in hepatocytes. Because of its central role in the clearance of solutes from portal blood, endocytosis might represent a significant mode of cellular transport. We investigated the mechanism of sucrose uptake in an isolated hepatocyte system. Liver cells were isolated by perfusion and collagenization of rat liver, followed by differential centrifugation. Hepatocytes were then incubated with 14C‐sucrose and harvested by spinning through oil in microfuge tubes. Radioactivity was standardized against DNA content. We found that sucrose uptake is concentration‐dependent from 5 μM to 100 mM and follows first‐order kinetics. Washout studies indicate that exocytosis is responsible for the dynamic equilibrium reached. Arrhenius analysis of temperature dependence yields a linear plot (Ea = 14.2 Kcal/mol). In addition, sucrose uptake is independent of cellular ATP levels. We conclude that sucrose is transported by fluid‐phase micropinocytosis in isolated hepatocytes and that this transport mechanism may be important in the uptake of diverse molecules into liver cells.
Intraclonal diversity of fibrosarcoma cells for the production of macrophage colony‐stimulating factor and granulocyte colony‐stimulating factor
Authors: Sakai Nobuo , Kubota Masao , Shikita Mikio , Yokota Masahiko , Ando Koichi 
Published: February 2005

AbstractA new cell line was established from fibrosarcoma that had spontaneously developed in a mouse. The cells were maintained growing in cultue for two years and constantly produced both macrophage colony‐stimulating factor (M‐CSF) and granulocyte colony‐stimulating factor (G‐CSF). Cloning of the cells by anchorage‐independent colony formation gave subclones showing the activity of producing M‐CSF and G‐CSF in different proportions, whereas no subclone produced G‐CSF without producing M‐CSF simultaneously. Recloning of the bipotential subclones again gave clonal derivatives producing two types of CSF in various proportions. The observed heterogeneity of the cloned cells seems to be an epigenetic phenomenon, because the cells resumed the G‐CSF producing activity in the absence of cell proliferation. After equilibrium was achieved, all of the subclones produced both M‐CSF and G‐CSF nearly in equal proportions. Tumorigenic and leukocytosis‐inducing activity of the cloned cells was nearly comparable with the activity of the original tumor cells.
In vitro effect of a thymic epithelial culture supernate or thymosin fraction 5 on rabbit platelet aggregation and intracellular cyclic AMP levels
Authors: Hashimoto Shuichi , Itoh Yukie , Kawaguchi Akiko , Mizuno Yoshio , Muraoka Matuo , Tsuchiya Masaharu 
Published: February 2005

AbstractSupernates of thymic epithelial cell culture (STEC) strongly inhibit aggregation induced by addition of adenosine diphosphate (ADP: 1 μM) or thrombin (0.5 unit per ml) to washed platelet suspensions and accelerated the restoration from ADP‐triggered aggregation. At the same time, STEC increased the level of platelet adenosine 3′,5′‐cyclic monophosphate (cyclic AMP) in a dose‐dependent manner. Depending on the concentration used, thymosin fraction 5 increased the level of intracellular cyclic AMP ranging between 5 and 100 μg per ml, as well as inhibiting ADP‐induced platelet aggregation. The activities of both STEC and thymosin fraction 5 were found to act exclusively on cyclic AMP phosphodiesterase activity in platelets. In contrast the supernates from Chang, HeLa, or HCC‐M cells did not affect platelet aggregation induced by ADP, but slightly increased the cyclic AMP level (Chang, HeLa). Within 2 min after the treatment with STEC, more than 50% of the maximum inhibitory activity on platelet aggregation and increases in intracellular cyclic AMP were observed. These activities disappeared following STEC treatment with pronase E. STEC activity was found predominantly in the 1,000–50,000‐dalton fractions. These activities were not altered when STEC was treated by adenosine deaminase. The level of prostaglandin E (PGE) derivaties in STEC was about two times that found in the control culture medium. These data suggest that the biological activity of STEC in the platelets might be attributed to thymosinlike polypeptides and PGE1.
Regulation of the glucose‐regulated protein genes by β‐mercaptoethanol requires de novo protein synthesis and correlates with inhibition of protein glycosylation
Authors: Kim Yong Kyu , Kim Kyu S. , Lee Amy S. 
Published: February 2005

AbstractTreatment of hamster fibroblasts with the sulfhydryl‐reducing agent β‐mercaptoethanol (β‐ME) results in increased synthesis of the glucose‐regulated proteins (GRPs). The most abundant protein species being induced in the GRP78, with a minor increase also observed for GRP94. The enhanced synthesis of the GRP94 and GRP78 is primarily due to an increase in the steady state levels of the two GRP transcripts. Although β‐ME has a general inhibitive affect on amino acid uptake and protein synthesis, compared to other protein synthesis inhibitors such as cycloheximide, puromycin, and amino acid analogue canavanine, β‐ME is a more potent inducer of GRP gene expression. In addition, the induction by low dosage of β‐ME requires de novo protein synthesis and is preceded by a drop in the rate of protein glycosylation. Our results support the hypothesis that denatured proteins can induce the GRP genes; however, a blockage ofsome post‐translocational processing step in the endoplasmic reticulum, as a result of β‐ME or other stress treatments, may provide the additional stimulation which transcriptionally activates the GRP genes to high levels.