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PubMed1983

Pancreatic endocrine cell fractions in erythroblastosis fetalis.

Pancreatic sections from 21 cases of rhesus disease and 20 control newborn infants of 30--40-wk gestational age were stained by the immunoperoxidase method for insulin, glucagon, somatostatin, and pancreatic polypeptide (PP). The fractional area occupied by each cell type was estimated, taking note of whether the gland contained PP-rich (ventral lobe) or PP-poor islets (dorsal lobe). In the PP-rich part of the pancreas, the volume fraction of all four endocrine cell types was significantly greater in the rhesus cases than in the controls. No difference was found between the two groups in the PP-poor part of the gland. The results show that abnormal development of the PP-rich part of the pancreas occurs in erythroblastosis fetalis. The localization of the changes to one part of the pancreas may explain some of the earlier conflicting reports on this topic.

Erythroblastosis, Fetal↗
PubMed1989

Tumor bed effect-induced reduction of tumor radiocurability through the increase in hypoxic cell fraction.

Two murine tumors, designated FSA and SA-NH, that exhibit strong tumor bed effect (TBE), were found to be less radiocurable if they grew in the preirradiated s.c. tissue. Tumors were transplanted into the right thighs irradiated with 30 Gy one day earlier, and were irradiated when they grew to 6 mm. The TBE-caused reduction in tumor radiocurability was manifested by the increase in TCD50 values. Tumor irradiation under hypoxic conditions increased TCD50 values less, and the hypoxic cell radiosensitizer misonidazole reduced TCD50 values more, when tumors grew in preirradiated than when they grew in unirradiated legs. This implies that TBE-induced increase in TCD50 was due to increase in hypoxic fraction of tumor cells. For 6 mm SA-NH tumor the estimated increase in hypoxic cell fraction was from the control value of 3% to 12%. Thus, TBE causes the reduction in tumor radiocurability through the increase in hypoxic fraction of tumor cells.

Aerobiosis↗
PubMed1995

The content of glutathione and glutathione S-transferases and the glutathione peroxidase activity in rat liver nuclei determined by a non-aqueous technique of cell fractionation.

Hepatocellular nuclei require glutathione, glutathione S-transferases (GSTs) and Se-dependent glutathione peroxidase (GPx) for intranuclear protection against damage from electrophiles or products of active oxygen. Data so far available from the literature on nuclei isolated in aqueous systems range from glutathione, GSTs and GPx either being absent altogether to being present in quantities in excess of those in the cytoplasm. This paper describes a small-scale preparation of a nuclear fraction from rat liver by a non-aqueous technique, designed to retain nuclear water-soluble molecules in situ, since low-molecular-mass compounds can diffuse freely into other compartments during aqueous separation. This non-aqueous procedure shows the nucleus to contain glutathione at 8.4 mM and soluble GSTs at 38 micrograms/mg of protein, the enrichment over the homogenate being 1.2-1.4-fold. Se-dependent GPx activity was also present in the nucleus (56 m-units/mg), although with slightly lower activity than in the homogenate (0.7-fold).

Animals↗
PubMed1975

Epstein-Barr virus-induced transformation of human leukocytes after cell fractionation.

The efficiency of transformation of human lymphocytes after infection with Epstein-Barr virus (EBV) was determined in fractionated and non-fractionated preparations derived from 16 human cord blood samples and two blood samples from adult donors. The transformation efficiency of macrophage-depleted leukocytes was consistently lower as compared to non-fractionated leukocytes. Additional depletion of B-cells resulted in a further decrease. Reduction of T-cells, however, did not influence significantly the transformation rate. In non-fractionated leukocyte cultures, as well as in macrophage-depleted and B-cell enriched cultures, colonies of transformed cells were regularly observed within the first week of cultivation. All cell lines established after EBV-infection revealed membrane-bound immunoglobulin. Reconstruction of macrophages-depleted, B-cell enriched or B-cell depleted cultures with autologous macrophages resulted in an increase of the transfromation efficiency up to the values of non-fractionated leukocyte preparations. Addition of heterologous human embryonic lung fibroblasts resulted in a similar increase. The results support the interpretation that EBV transforms only those cells of the hematopoetic system which are derived from the bone-marrow entity. The transformation efficiency is considerably increased by co-cultivation of lymphocytes with macrophages and heterologous human fibroblasts which seem to excert a feeder-layer effect by enhancing survival of lymphocytes in vitro.

B-Lymphocytes↗
PubMed1979

Metabolism and binding in vitro of 5 alpha-androstane-3 beta, 17 beta-diol and of 5 alpha-androstane-3 alpha, 17 beta-diol in cell fractions of rat ventral prostate and liver.

Rat ventral prostate and liver were investigated for the binding in vitro to particulate fractions and for the metabolism of 5 alpha-androstane-3 beta, 17 beta-diol. Comparative investigations were carried out on the metabolism of 5 alpha-androstane-3 alpha, 17 beta-diol. Preparations of the liver were investigated in order to establish the organ specificity of the method. In the prostate, the bulk of the metabolites of 5 alpha-androstane-3 beta, 17 beta-diol was present as steroids of high polarity. Of the less polar metabolites, 17 beta-hydroxy-5 alpha-androstan-3-one, 3 beta-hydroxy-5 alpha-androstan, 17-one and 5 alpha-androstane-3 alpha, 17 beta-diol were detectable. The binding of a 5 alpha-androstane-3 beta, 17 beta-diol to mitochondria and microsomes was unspecific. In the liver, among the less polar metabolites, 3 beta-hydroxy-5 alpha-androstan-17-one was the main metabolite, and the binding was unspecific. The main metabolite in the prostate homogenate of 5 alpha-androstane-3 alpha, 17 beta-diol was 17 beta-hydroxy-5 alpha-androstan-3-one. The portion of highly polar steroids was very low. The portion of unmetabolized hormone was distributed almost equally among the different cell preparations except the nuclei, in which 17 beta-hydroxy-5 alpha-androstan-3-one was higher and 5 alpha-androstane-3 alpha, 17 beta-diol was lower than in the remaining cell fractions.

Androstane-3,17-diol↗
PubMedDate not supplied

[The effect of ionizing radiation on the functional properties of hemoglobin from fractionated cells of dog bone marrow].

Cell populations of dog bone marrow enriched by erythroid cells were obtained by fractionation in a sucrose density gradient. Functional properties of the haemoglobin isolated from nucleate erythrocyte precursors were studied during the radiation injury development. The haemoglobin of later nucleate forms of the erythroid series of irradiated dog bone marrow exhibited an increase in its affinity to oxygen.

Animals↗
PubMed1977

[Immunologic properties of various cell fractions of a wild strain and a mutant strain of Saccharomyces cerevisiae Hansen].

Some fractions of the Saccharomyces cerevisiae cell wall have been prepared by the action of Helix pomatia juice on intact cells. Immunosera were obtained by injecting rabbits with these fractions. Immunofluorescence reactions, obtained with these sera, show that some fractions of mannopeptides when extracted from a "smooth-colony" mutant strain, have lost antigenic determinants.

Cell Wall↗
PubMed2000

Identification of human GATA-2 gene distal IS exon and its expression in hematopoietic stem cell fractions.

Transcription factor GATA-2 is essential for the proper function of hematopoietic stem cells and progenitors. Two first exons/promoters have been found in the mouse GATA-2 gene, and a distal IS promoter shows activity specific to hematopoietic progenitors and neural tissues. To ascertain whether the two-promoter system is also utilized in the human GATA-2 gene, we isolated and analyzed a P1 phage clone containing this gene. The nucleotide sequence of the human GATA-2 gene 5' flanking region was determined over 10 kbp, and a human IS exon was identified in the locus through sequence comparison analysis with that of the mouse GATA-2 IS exon. RNA blotting and reverse-transcribed PCR analyses identified a transcript that starts from the IS exon in human leukemia-derived cell lines. The IS-originated transcript was also identified in CD34-positive bone marrow and cord blood mononuclear cells, which are recognized as clinically important hematopoietic stem cell-enriched fractions. Phylogenic comparison of the human and mouse GATA-2 gene sequences revealed several regions in the locus that exhibit high sequence similarity. These results demonstrate that the GATA-2 gene regulatory machinery is conserved among vertebrates. The fact that the human IS promoter is active in the hematopoietic stem cell/progenitor fraction may be an important clue for the design of a vector system that can specifically express various genes in hematopoietic stem cells and progenitors.

Animals↗
PubMed1995

Enrichment for Th1 cells in the Mel-14+ CD4+ T cell fraction in aged mice.

CD4+ T cells from young and aged mice were sorted into Mel-14+ cells which are regarded as naive cells and Mel-14- cells which are regarded as memory cells. These subsets were stimulated in short-time cultures with anti-CD3 or anti-CD3/anti-CD28 in order to determine the presence of Th1 and/or Th2 cytokines. Based on the simultaneous production of IL-2, IL-4, IL-10, and IFN-gamma upon anti-CD3 stimulation by Mel-14- cells from young and aged mice, it is concluded that this cell population comprises Th1, Th2, and/or Th0 cells. Mel-14+ cells from young mice only secrete substantial amounts of IL-2 in the presence of anti-CD28 as a costimulatory signal and can therefore be regarded as Th precursor cells. By contrast, Mel-14+ cells from aged mice responded to anti-CD3 alone, not only by the production of IL-2 but also by the production of high amounts of IFN-gamma and minute amounts of IL-4 and IL-10, suggesting that these "naive" cells in aged mice are enriched for Th1 cells. This was not due to lack of CD28 triggering since anti-CD28 enhanced IFN-gamma as well as IL-4 and IL-10 to a similar extent. Our data therefore indicate that Mel-14 is not exclusively expressed on naive CD4+ T cells.

Aging↗
PubMed1971

Cell fractionation and arrangement on fibers, beads, and surfaces.

A new method, fiber fractionation, has been used to isolate and separate cells. The cells are adsorbed to fibers covalently coupled to molecules such as antigens, antibodies, and lectins which can bind specifically to cell-surface components. The cells are then removed mechanically by plucking the taut fibers. Alternatively, competitive inhibitors of binding may be used to remove the cells at a lesser rate. Successful fractionations have been achieved by varying the degree of derivatization of the fibers by the lectin concanavalin A. Lymphoid cells have been separated by the use of different antigens coupled to the fibers. The method may also be used for specific fixation and manipulation of viable cell populations in culture. In addition to fibers, beads and surfaces have been specifically derivatized and used to achieve different geometrical arrangements of the cells.

Animals↗
PubMed2004

A cell fractionation approach for the quantitative analysis of subcellular drug disposition.

PURPOSE: The purpose of this work was to develop and validate a method that can be used to quantify drugs associated with intracellular compartments. METHODS: The human leukemic cell line U-937 was used to evaluate the distribution of model compounds with known and different subcellular distribution profiles. Lysotracker Red is a lysosomal vital stain and doxorubicin is an anticancer agent with a strong propensity for nuclear accumulation in U-937 cells. After incubation with compounds, cells were separated into fractions containing nuclei, cytosol, and cytoplasmic organelles (lysosomes, mitochondria, Golgi apparatus). Compounds contained within isolated fractions were subsequently extracted and analyzed by high-performance liquid chromatography. Diffusion of compounds from isolated organelles was also investigated. RESULTS: Using this approach we have shown that the model compounds Lysotracker Red and doxorubicin preferentially accumulated within lysosomes and nuclei, respectively. We have reproducibly determined concentrations of these compounds in each of the cellular fractions. We have also shown that diffusion of these compounds from isolated cellular compartments was minimal during the time required to complete the experimental procedure. CONCLUSIONS: The analytical approach described in this manuscript yielded reproducible quantitative data regarding the intracellular distribution of model compounds in U-937 cells. With the aid of a relatively sensitive analytical assay, this technique should be useful for most drugs that have a specific concentrative mechanism for organelle accumulation similar to Dox and LTR.

Cell Fractionation↗
PubMed1995

Peripheral blood stem cell collection in a patient with chronic myelogenous leukemia and a high circulating nucleated red cell fraction.

A high level of circulating nucleated red blood cells (NRBC) in patients with chronic myeloproliferative syndromes could potentially complicate peripheral blood stem cell (PSC) collection. The mononuclear NRBC might comprise a significant fraction of the total mononuclear cells in the final product. We report a successful PSC collection in a patient with more NRBC than WBC in the peripheral blood. A 27-year-old man with chronic myelogenous leukemia underwent eight PSC collection procedures, seven using the Cobe Spectra (Spectra) and one using the Fenwal CS3000 Plus (CS). PSC product manipulations to remove NRBC were unnecessary. As assessed by post-collection NRBC: WBC ratio as a percent of the initial ratio, Spectra selectively harvested mononuclear leukocytes over NRBC. The collected products had a mean NRBC: WBC ratio that was 3.4% of the peripheral blood ratio. Adequate numbers of mononuclear leukocytes were collected with less than 6% NRBC contamination. The single CS procedure resulted in a comparable NRBC reduction efficiency as the Spectra. We conclude that PSC harvest using automated blood cell separators from patients with a high level of circulating NRBC may result in a product with an acceptable number of NRBC.

Adult↗
PubMed1971

Differences in distribution of esterase between cell fractions of rat liver homogenates prepared in various media. Relevance to the lysosomal location of the enzyme in the intact cell.

The distribution of esterase in subcellular fractions of rat liver homogenates was compared with that of the lysosomal enzyme acid phosphatase and the microsomal enzyme glucose 6-phosphatase. Most of the esterase from sucrose homogenate sediments with glucose 6-phosphatase and about 8% is recovered in the supernatant. However, up to 53% of the esterase can be washed from microtome sections of unfixed liver, in which less cellular damage would be expected than that caused by homogenization. About 40% of both esterase and acid phosphatase are recovered in the soluble fraction after homogenization in aqueous glycerol or in a two-phase system (Arcton 113-0.25m-sucrose), although glucose 6-phosphatase is still recovered in the microsomal fraction of such homogenates. The esterase of the microsomal fraction prepared from a sucrose homogenate is much more readily released by treatment with 0.26% deoxycholate than are other constituents of this fraction. The release of esterase from the microsomal fraction by the detergent and its concomitant release with acid phosphatase after homogenization in glycerol or the two-phase system suggests that a greater proportion of esterase may be present in lysosomes of the intact cell than is indicated by the results of standard fractionation procedures.

Acid Phosphatase↗
PubMed1982

Generation of a cloned NK cell line derived from the "null cell" fraction of human peripheral blood.

The present studies were designed to determine the conditions for generation of human NK clones. First the "null cell" (NC) fraction of human peripheral blood mononuclear cells, which contains the NK effectors, was purified using negative selection with anti-T3, anti-T8, anti-B1, and anti-Mo2 monoclonal antibodies. Subsequently, NC were cloned by limiting dilution using a combination of phytohemagglutinin (PHA) and lymphocyte-conditioned medium (LCM) as an initial stimulus. Colonies could be easily obtained with this procedure, but the maintenance of long-term growth of the cultures represented a major problem. A cloned cell line termed JT1 was generated and has been proliferating continuously in culture for more than 6 mo. The phenotype of JT1 cells was analyzed several times with a series of monoclonal antibodies. These cells did not express surface markers related to thymic (T3-, T4-, T8-, T11-), B cells (B1-, J5-), or myelomonocytic (Mo1-, Mo2-, MY7-) differentiation. In contrast, 95% of JT1 cells reacted with the anti-T10 monoclonal antibody. T9, Ia, and J2 antigens were also present on JT1 cells, but their expression appeared variable from one determination to another. This cloned cell line maintains a strong cytotoxicity against common NK targets, such as K562 and Molt 4 cell lines, and a moderate ADCC activity. In addition, after several months in culture, JT1 cells are still capable of being regulated by interferon, because this lymphokine rapidly enhances cytotoxicity against K562 cells.

Antibodies, Monoclonal↗
PubMed1986

Effect of human recombinant interleukin 2 on natural killing of low density Percoll fraction cells.

Human recombinant IL-2 (R IL-2) was used to validate the ability of this lymphokine to increase NK cell activity. It was found that R IL-2 was able to augment the K562 lytic activity of phagocyte-depleted mononuclear cells of low density in a dose dependent manner. This phenomenon was detectable after 24 h of incubation. Low concentrations of R IL-2 were sufficient for the activation of natural killing when the incubation time was longer than 24 h. Furthermore, IL-1 exerted an additive effect on R IL-2 induced augmentation of natural killing after 24 h, but not after longer incubation periods. Lymphocyte culture derived (L) and R IL-2 had similar effects on the K562 cytolytic potential of cells contained in low density fractions. The highest cytolytic activity was observed when Leu11a+ cells were incubated with IL-2. IL-2 induced K562 cytolytic activity was also seen after incubation of low density Leu11- cells for 48 h, 72 h, or 7 days. In cultures of low density Leu11- cells incubated with IL-2 for 7 days, a proportion of cells became Leu11+. From these findings we conclude that low density Leu11- cells are pre-NK cells which acquire natural killing potential under the influence of IL-2.

Cell Differentiation↗